Expanding Sustainable Land Governance: A Geospatial Framework for Incorporating Natural Parks into Urban Cadastres—Lessons from Darke de Mattos Park, Rio de Janeiro

Abstract

Contemporary metropolises, particularly those in the Global South, grapple with the complex challenge of balancing urban development with environmental conservation. In such contexts, forest remnants often face constant threats from illegal urban encroachment and insufficiently defined boundaries, which undermine conservation efforts and hinder effective legal enforcement. This study explores cost-efficient, geographic-information-technology-driven solutions to improve the management of conservation units and incorporate them into cities’ multipurpose land cadastres. By employing tools such as a remotely piloted aircraft, total stations, and GNSS receivers, this work highlights the pivotal role of geotechnologies in safeguarding the urban natural heritage. These technologies not only address the pressures of urban expansion but also enable continuous monitoring and impact assessment through geographical information systems (GISs). To illustrate these applications, this study examines a case study from Rio de Janeiro, Brazil, the Darke de Mattos Municipal Park, to demonstrate how accurate geographic data can significantly enhance planning and management efforts while maintaining cost-effectiveness.

1. Introduction

Many cities are home to significant forest remnants, which preservation is crucial for maintaining the quality of life of the cities’ residents, ensuring environmental comfort, protecting fauna and flora, and promoting environmental education. These green areas play an essential role in cities’ ecological balance, contributing to climate regulation, air purification, water resource conservation, and the mitigation of impacts such as floods and urban heat islands [1,2,3,4]. Furthermore, they serve as refuges for diverse species of fauna and flora, many of which are endemic or endangered, underscoring the importance of their conservation for local biodiversity [5,6,7].

The preservation of these forest remnants is also directly linked to the well-being of the population, providing spaces for leisure, recreation, and connection with nature, which are fundamental for physical and mental health [8,9,10,11,12]. Additionally, these areas are vital for environmental education, serving as living laboratories where the population, especially children and young people, can learn about the importance of environmental conservation and sustainable development [13,14,15,16].

In an era of rapid urbanization, proactive planning to safeguard natural spaces from encroachment has become critically urgent. As [17] projects, nearly all the population growth this century will occur in urban areas, with global metropolises, like Rio de Janeiro, facing continued expansion pressures. This reality makes the protection of urban natural parks absolutely essential, as unchecked development and weak enforcement persistently threaten these vital ecosystems. Strategic land-use planning must act now to preserve these green spaces before urban sprawl renders conservation impossible. The implementation of effective public policies, the strengthening of legal protection mechanisms, and the engagement of civil society are essential to ensure the preservation of these areas [18,19]. Integrating these forest remnants into the city’s multipurpose land cadastre [20], with precise delimitations and legal recognition, is an important step toward securing their protection and sustainable management [21,22,23,24], benefiting both the environment and the residents of Rio de Janeiro.

In the multipurpose land cadastre, the basic unit is the parcel [25]. As such, any portion of the territory, whether public or private, must be modeled by one or more contiguous parcels. Private parcels include lots, plots, properties, and other areas considered as private property. Public parcels consist of all the spaces of public interest, such as streets, squares, parks, water bodies and certain right-of-way areas [26,27,28,29]. Although land cadastre legislation changes from country to country, usually, those standards remain the same across the world.

In this context, natural parks should be modeled as public parcels, with boundaries defined by public decrees [30]. Nevertheless, many of them are affected by lots originating from some formal urban land subdivision process. In such cases, the areas of the lots that overlap with the parks are often considered as permanent preservation areas or legal reserves, restricting land use on these properties and, thus, classified as territorial objects. This complicates the autonomy of public administration in managing these areas, which is further exacerbated by the total or partial lack of knowledge of their exact boundaries. Therefore, it is important that these parks be properly registered as parcels [31], definitively separating them from any private portion and integrating them permanently into the municipal cadastre, minimizing disputes and litigation, and providing legal security for the park and the public administration for appropriate actions [32,33].

This raises a challenge in defining the boundaries of natural parks as certified parcels, given their large territorial extents and the high number of vertices. In most cadastral scenarios, vertices must meet a positional accuracy requirement of less than 10 cm and be materialized on the ground [34,35,36], which can be highly challenging or even impossible to implement, as in some cases, there may be hundreds or even thousands of such vertices. Such demands have, for many years, prevented planning agencies from properly knowing and mapping natural parks. This is especially true in countries under development, where conservation efforts can be a rather new development and the cost of conducting detailed surveys is a major deterrent.

Therefore, the use of more accessible geotechnologies that guarantee, at a minimum, standardized positional accuracy could be a feasible solution to address this issue, ensuring that the areas are accurately characterized. A photogrammetric aerial survey using a remotely piloted aircraft (RPA), where the geometric and radiometric resolutions of the generated images can provide accuracies better than 8 cm, could serve as a specific solution for certifying parcels of this type [37,38,39]. Subsequently, as adjacent parcels are certified through the necessary terrestrial surveys, the vertices could be gradually materialized, thus providing a fit-for-purpose approach to map environmental land cadastres.

This article presents a straightforward yet precise methodology applied in the Darke de Mattos Natural Park, situated on Paquetá Island in the Municipality of Rio de Janeiro. The approach combines high-accuracy geodetic surveys with remotely piloted aircraft (RPA) surveys to generate a detailed map of the park and explore potential scenarios for its future integration with an adjacent natural remnant, Morro do Vigário. Although this study focuses on a specific case, the methods described are highly adaptable and reproducible in other contexts. This framework offers a valuable model for the mapping and enhancement of natural parks, providing a foundation for improved conservation and management practices.

Objectives for This Study

The integration of the Darke de Mattos Natural Park with the native forest remnants of Morro do Vigário presents a promising opportunity to enhance the protection of Atlantic forest biodiversity, improve habitat connectivity, and enable the effective management of the annexed area. However, this integration must be supported by a reliable spatial database fully aligned with the municipality’s multipurpose land cadastre to ensure both physical (e.g., walls and fences) and legal (e.g., proper land titles) safeguards.

A critical step in implementing the cadastre is the expropriation of the unused lands of Morro do Vigário. Expropriation entails the transfer of private property rights to public ownership, compensated through public debt securities [40]. This process can be initiated because of non-compliance with the property’s social function—specifically, the absence of subdivision, construction, or productive use within five years of progressive land taxation [40,41].

Once the lands are under public ownership, the boundary demarcation process begins. Local regulations must be followed, particularly regarding parcel-mapping accuracy. For this study, a planimetric positional accuracy of 8 cm for boundary vertices was targeted, allowing for up to three times this tolerance in cases of multiple distinct surveys [42,43]. Similar precision standards are common in cadastral norms worldwide.

However, the high costs associated with geoinformation technologies often hinder the establishment of legally sound park boundaries in developing countries. Traditional geodetic or aerial surveys may exceed municipal budgets, diverting resources from more economically feasible projects.

To address this challenge, this study proposes a cost-effective yet precise ensemble of geotechnologies to support local governments in cadastral mapping for park management and conservation. The primary objective is to develop a replicable methodology that ensures accurate mapping, land registration, and legal protection for natural parks without prohibitive expenses.

Secondary objectives include

• Providing a detailed current plan of Darke de Mattos Natural Park and its parcel;
• Proposing geospatial scenarios for its integration and expansion with the Atlantic forest remnant of Morro do Vigário, which take into account both social and environmental concerns while ensuring proper land governance;
• Incorporating constitutive elements of the multipurpose land cadastre (MLC), such as vector-based boundary delineation and descriptive boundary memorials, within the proposed scenarios.

2. Study Area

2.1. Paquetá Island

Paquetá Island (Figure 1), located in northeastern Guanabara Bay, is renowned for its scenic beauty and rich biodiversity. It derives its name possibly from the Tupi term for “place of shells” [44]. Indigenous groups, like the Tamoios, likely used it temporarily because of its lack of freshwater. During the sixteenth-century Franco–Portuguese conflict, the French briefly held the area before Portuguese colonization. Development later split between the north (Campo), focused on farming and livestock, and the south (Ponte), known for lime production and shipbuilding. In the nineteenth century, Dom João VI frequented the island, and José Bonifácio sought refuge there [45]. Romantic-era artists, including Machado de Assis, celebrated its natural beauty.

2.2. Darke de Mattos Natural Park

Following the division of the island’s two original sesmarias (land grants), Paquetá underwent significant transformation, first through agricultural plantations and lime kilns, then through progressive subdivision and urbanization, leading to the emergence of numerous chácaras (small farms), with properties gradually being divided into smaller lots. Among these, the Chácara do Morro da Cruz in the island’s southern sector (now the Darke de Mattos Natural Park) holds particular historical significance, having been originally owned by the Bulhões family in the late nineteenth century as a rice-processing mill for husked rice from Baixada Fluminense [44] and later hosting the short-lived Agricultora industrial textile factory before being acquired by Dr. Pinheiro Freire and then sold to Bhering de Mattos, whose son Darke renovated the estate into a social venue before it passed to his sister Dona Adélia de Mattos, who renamed it Parque Darke de Mattos in his honor.

The municipality expropriated the property in 1975 [46,47] (Municipal Decrees No. 199/1975 and 259/1975) and converted it to a public park [48] through Decree No. 394/1976. Its conservation status was further elevated in 1999 when Decree No. 17,555 designated it as an Area of Cultural Environmental Protection (APAC), recognizing both the park and adjacent Morro do Vigário for their historical, landscape, and cultural value [49].

The park’s legal framework was refined in 2003 through Decree No. 22,662 [50], which reclassified it as a “Municipal Natural Park” under Brazil’s National Conservation Unit System. This designation reflects its dual mission of preserving ecologically significant ecosystems while facilitating scientific research, environmental education, and nature-based recreation. This decree specifically highlights the park’s role in maintaining biodiversity while accommodating responsible public use.

Today, Darke de Mattos Natural Park offers various amenities, including pedestrian paths, picnic areas, benches and recreational facilities, that serve both residents and visitors [51]. However, balancing human use with ecological preservation remains challenging, particularly because of invasive species, such as Leucaena leucocephala (Figure 2), introduced from Mexico and Central America in the 1940s for landscaping. This aggressive species outcompetes native vegetation through dense canopy growth and rapid regeneration, posing a major threat to the park’s ecosystems [52].

2.3. Biodiversity and Environmental Relevance of Paquetá

Paquetá Island maintains fragments of secondary Atlantic forest amidst its urban landscape, with the Darke de Mattos Natural Park and Morro do Vigário representing important ecological refuges. Though geographically separate, these areas share notable biodiversity because of their proximity and similar environmental conditions. The vegetation consists primarily of regenerated forest, demonstrating nature’s resilience despite urban pressures.

The flora includes native species, such as the fig tree (Ficus guaranitica (Moraceae)), garlic wood (Gallesia integrifolia), yellow mombin (Spondias lutea (Anacardiaceae)), and the endangered sapotiaba (Bumelia obtusifolia (Sapotaceae)). These coexist with introduced species, including the jackfruit tree (Artocarpus heterophyllus (Moraceae)), African baobab (Adansonia digitata (Bombacaceae)), and the invasive leucena (Leucaena leucocephala) [53]. The fauna is equally diverse, featuring the house wren (Troglodytes aedon), various hummingbird species (Phaethornis ruber and Eupetomena macroura), the common opossum (Didelphis marsupialis), and the threatened orange-winged amazon parrot (Amazona amazonica) [53].

A significant botanical discovery occurred in 2022, when municipal environmental experts identified Funifera insulae Nevling, a plant species endemic to Paquetá Island, on Morro do Vigário [54]. Classified as critically endangered (CR B2ab ii, iii) in the Red Book of Rio de Janeiro’s Endemic Flora [55], this species faces extreme risk because of severe habitat fragmentation and declining habitat quality [56]. Urban expansion into remaining forest areas has drastically reduced the species’ limited habitat, creating an urgent conservation challenge.

Morro do Vigário, standing at 69 m above sea level, contains Paquetá’s largest Atlantic forest remnant. Its southeastern boundary meets Guanabara Bay, while other sides face residential development. The hill’s varied topography has unfortunately facilitated the growth of informal settlements, with slopes gradually being occupied by irregular housing. This has resulted in one of the island’s three recognized favelas.

The Associação de Moradores do Morro do Vigário, formally established in 1995, represents a community that first emerged between 1976 and 1985 according to IPP records. Census data reveal significant growth, from 95 households occupying 9243 m² in 2010 to 118 households across 12,082 m² in 2022 [57]. Although Law 3279/2001 designated the area as an area of special social interest (AEIS) to enable urbanization programs [58], reality reveals troubling contradictions. Current development patterns conflict with urban planning standards, inadvertently encouraging further encroachment into forested slopes and accelerating native vegetation loss. This tension between community needs and environmental protection presents complex challenges for sustainable development on the island.

2.4. Cadastral Elements Pertaining to Darke de Mattos and Morro do Vigário

The urban cadastral composition of Paquetá Island was examined through comprehensive research utilizing multiple geospatial data sources, including alignment and parcel plans, topographic maps, orthoimages, and digital terrain models. This multilayered approach aimed to establish a complete understanding of the island’s land organization.

The municipality’s GeoPAL online service (Figure 3) reveals a notable gap in cadastral documentation, with no approved plans existing for Darke de Mattos Natural Park itself. Available records are limited to adjacent areas of Morro do Vigário, and of poor quality (thus not entirely readable), as exemplified by the approved parcelling project (PAL-in Portuguese: Projeto Aprovado de Loteamento) 25462 (Figure 4).

A detailed examination of historical subdivision plans, including PAL 25462, from the mid-twentieth century uncovered significant limitations in their geodetic and cartographic foundations. These documents lack precise coordinate references and standardized scales, resulting in substantial uncertainties regarding their spatial accuracy and reliability for contemporary planning purposes.

The only available high-precision maps were an old topographic map at a scale of 1:500, covering the park per se, and the municipality’s 1:2000 cadastral map. The 1:500 map (Figure 5) was produced by the company GeoAgri LTDA in 1976 and digitized as a part of the Memória da Paisagem Carioca (Memory of the Carioca Landscape) Project. Despite its historical and documentary importance, it is important to note that the map was initially not georeferenced, being an analog input, which limited its direct application in precise spatial analyses. Additionally, the original document was lost, and the only remaining digital file was of poor quality, as evidenced by the figure.

The cadastral map, at a scale of 1:2000 (Figure 6), was produced through photogrammetric restitution by Topocart Aerolevantamentos S.A., from aerial surveys conducted in 2013. The 1:2000 scale allows for a detailed analysis of the area, although it is not suitable for the parcel-level cadastre. Therefore, although the 1:2000 map is a reference document, it cannot be used as the primary data source for the work in question because certain features, such as storm drains, culverts, curbs and others, are not identified in this product because of the scale. Its only importance in this project lies mainly in planning the survey and comparing the final results of the drone-based aerial survey and photogrammetric processing.

The lack of high-precision, large-scale surveys poses a fundamental challenge for parcel certification, severely hindering effective territorial management in the study area. The current cadastral map lacks sufficient reliability for two key reasons: First, it was produced before the implementation of Brazil’s Technical Specifications for the Quality Control of Geospatial Data [43], which establish official error standards for large-scale cartographic products. Second, even if compliant, its permitted planimetric error of 34 cm falls short of Brazil’s urban cadastral requirements, which mandate 8 cm accuracy with physically demarcated boundaries [42]. Although adequate for municipal planning and taxation purposes, these maps cannot serve as definitive sources for parcel delineation or land registry. Such applications require detailed 1:1000 or 1:500 scale plans that strictly adhere to the 8 cm accuracy standard. This highlights the urgent need for new surveys that meet modern technical and regulatory standards.

Further analysis of the General Registry of Real Estate (RGI) revealed limited geospatial data. Although Paquetá’s real estate registry maintains computerized records, it lacks critical geospatial information. Existing documentation—such as topographic plans and georeferenced descriptive memorials—only provides basic parcel details (e.g., boundary descriptions, measurements, and addresses) without essential geodetic coordinates for boundary vertices [59].

Additionally, the decrees establishing the park’s original status [46,47,48] do not define precise boundary coordinates, only generic definitions, such as street names and parcels’ generic descriptions. Because these are unknown, precise boundaries must be determined based on physical features identified in the field.

As a result, neither Darke de Mattos Natural Park nor its potential expansion area in Morro do Vigário can be accurately linked to legally defined land parcels. This presents a major planning constraint, as proper cadastral parcels require the following:

• Georeferenced boundary vertices within an established geodetic system;
• Unique identification codes;
• A consistent legal status, all of which are currently absent in the study area [60].

The integration of Darke de Mattos Natural Park with the native forest remnants on Morro do Vigário is essential to strengthen Atlantic forest biodiversity conservation, enhance habitat connectivity, and ensure sustainable management of the expanded protected area. However, this initiative requires a precise and legally enforceable cadastral framework aligned with the municipality’s multipurpose land cadastre (MLC) to address both physical (e.g., fencing) and legal (e.g., land tenure) safeguards.

3. Materials and Methods

3.1. Equipment and Software

For the execution of the fieldwork, the following equipment was used:

• Two GNSS receivers (base and rover) X91R, by CHC Nav (Shanghai, China), supporting carrier wave frequencies L1, L2, and L5 and the GPS, GLONASS, GALILEO, and BEIDOU constellations;
• A Phantom 4 RPA (remotely piloted aircraft), by DJI (Shenzhen, China) with RTK GNSS positioning, an accuracy of 1 cm + 1 ppm (horizontal) and 1.5 cm + 1 ppm (vertical), and 20 MP camera with a 1-inch CMOS sensor;
• An aluminum tripod with a circular bubble level;
• An aluminum bipod with a rod and a circular bubble level.

In addition to this equipment, the following software was used for processing: QGIS 3.40.7 ’Bratislava’, Trimble Business Center 2024.00, CHC Geomatics Office 2.0, and Agisoft Metashape 2.1.8.

3.2. Ground Control Point Survey

The initial selection of control points was carried out using the 1:5000 orthoimage of Paquetá Island and Google Street View to remotely identify locations that could later serve as suitable candidates. The point selection was based on visible and accessible features for the field team, ensuring data collection feasibility (Figure 7).

On the day before the aerial survey, the field team visited Paquetá to conduct reconnaissance and pre-mark the control points, which were marked on the ground using spray paint applied over a stencil. The markings were in the shape of a cross, with approximately 20 cm for each section—large enough to be captured by the aerial photographs. Additionally, each marking was identified with their name to facilitate location during the processing stage. Thus, to enhance visibility in the images, the markings were placed in unobstructed locations, mostly on manhole covers and their edges, as shown in Figure 8.

Ground control points (GCPs) were strategically placed only along the edges of each photogrammetric block to ensure proper georeferencing while minimizing their number. These GCPs also served as tie points to accurately stitch adjacent blocks together during processing, seeking an optimal geometry such as that in [61]. Although a limited quantity was used, the selection was carefully planned to maintain sufficient accuracy while keeping the fieldwork efficient—allowing the entire GCP deployment to be completed within a single day. This approach balanced precision with practicality, reducing both the logistical effort and time in the field.

For surveying the control points, the CHCNav X91R receiver was used. Initially, the coordinates of point P01 were determined using the long-duration static relative positioning method, which served as the “starting point” for surveying the other GNSS points on the island (Figure 9). The tracking duration was four hours. According to [62,63], a tracking period from one to three hours is recommended for baseline lengths of up to 20 km. In this study, the reference station used for this method was the RJNI station (Niterói), a part of the RBMC (Rede Brasileira de Monitoramento Contínuo-Brazilian Network for Continuous Monitoring) [64], and the distance from the baseline to P01 was approximately 16 km.

It should be noted that P01 belongs to the geodetic station network of the Brazilian Geodetic System. It is an SAT (satellite station) planialtimetric station, identified by code 8114113 (station number and name) and described by the IBGE geodetic marker 3101A (Figure 9). Nevertheless, we chose to track it again relative to the RBMC station in Niterói for a period of four hours (the total duration of the survey). As a result, its coordinates were resolved with extremely high precision, making it suitable as a reference for the other survey points.

For the remaining points (from P02 to P08), the rapid static relative positioning method was adopted. According to [65,66], this method is similar to that used for P01 but with a shorter observation time, limited to a maximum of 20 min, and the receiver is turned off between sessions. The observation collection rate was post-processed at 15-second intervals, which is consistent with the sampling interval provided by RBMC stations.

A series of supplementary points (from P9 to P17) was also obtained. These points were not used in the photogrammetric processing of the park and Morro do Vigário (because they fall outside the study area). Their importance lies in providing a more precise georeferencing of other cartographic materials that encompass the whole island, thus making them compatible with the outcome of the proposed cadastral survey

In post-processing, the baselines of the control points were processed using Trimble Business Center software. The reference for adjusting the coordinates of point P01 was the RJNI station (code SAT96361) and the ONRJ station (code SAT93921), both a part of the RBMC and active at the time of this work’s publication. After the adjustment between the stations and P01, a triangulation network was established among the three stations, improving the accuracy of P01’s coordinates.

The remaining points were adjusted using the same procedure, now referencing P01, which had already been adjusted. This was possible because of simultaneous observations across all the stations. This planning ensures the resolution of receiver ambiguities and the removal of errors associated with receiver and satellite clocks [65,67]. After the adjustments, all the points underwent quality control measures to ensure that errors were in accordance with the scale and the accuracy required for derived cadastral products.

3.3. Flight Planning and Photogrammetric Processing

The UAV survey was carefully planned to account for the study area’s topography, particularly Morro do Vigário, a 69 m hill at its center. To maintain visual line-of-sight and manage battery constraints, the area was divided into three flight zones (Figure 10). Each zone had a designated homepoint (takeoff location), strategically positioned to allow safe return in case of emergencies—for instance, homepoint 2 was placed within flight area 1. Flights were conducted at a 100 m altitude above each homepoint to ensure high-resolution imagery while compensating for elevation changes. Authorization was obtained from DECEA (Brazil’s airspace control authority) prior to the June 26th survey.

The UAV followed pre-programmed flight lines, with 80% longitudinal and 70% lateral overlaps, following photogrammetric best practices [68,69]. Images were geotagged in real time using an onboard GNSS RTK system. Post flight, the data were processed in Agisoft Metashape, using structure-from-motion (SfM) and multiview stereo (MVS) techniques [70,71], generating a dense point cloud [72] that was later classified to isolate ground points for DTM generation. The resulting orthomosaic (Figure 11) was quality-checked against official base maps, with contour lines extracted at 1 m intervals.

An orthomosaic comprises distortion-corrected aerial images transformed from central to orthogonal projections [73,74], requiring a DEM for orthorectification to numerically represent terrain surfaces [75]. Using Agisoft Metashape with UTM coordinates, we applied structure-from-motion and multiview stereo techniques [70,71], aligning images via GCPs and algorithmically generated tie points.

After the manual refinement of misaligned points, we generated a dense 3D point cloud [72] through tie point matching [76], where increased density improved model accuracy [77]. Automatic classification isolated ground points from vegetation and structures to create the DEM and subsequent orthomosaic. From the DTM (ground-only DEM), we extracted 1 m interval contour lines (Figure 11), performing smoothing and elevation validation for the final product’s clarity.

After extracting the contours, necessary adjustments were made, such as smoothing the lines to eliminate potential noise caused by irregularities in the DTM, as well as verifying the attributes related to the elevation of each contour, to facilitate the understanding of the final product.

Finally, a quality analysis of these geospatial products was performed based on

• Root-mean-square errors from the photogrammetric bundle adjustment;
• The visual comparison of the orthomosaic with official base maps from Rio de Janeiro City Hall;
• The selection of known coordinate points and error analysis relative to their equivalents in the digital cartographic product (orthomosaic).

The following maps and plans were then created from the dataset:

• An updated orthophoto map of Darke de Mattos Park, showing its current physical boundaries;
• A vector feature dataset and a 1:1000 plan of Darke de Mattos Park, showing its current physical boundaries;
• An orthophoto map of the surroundings of Darke de Mattos Park, including Morro do Vigário;
• A series of four different plans, integrating Morro do Vigário into the parcel that encompasses Darke de Mattos Park, thus allowing for its possible expansion.

Regarding the last item, these scenarios for a new parcel were developed to address the need to delimit Morro do Vigário, particularly the remaining Atlantic forest area. The parcels were vectorized over the orthophoto to obtain a physical record of the study area. The delimitation was carried out to contain urban expansion and ensure the necessary environmental protection for the area to be legally incorporated into the administration of Darke de Mattos Municipal Natural Park (Figure 12).

Also, it is important to mention that the park’s current physical boundaries differ from what was originally established by decree in 1975. Some areas meant to be a part of the park include housing zones—a discrepancy not fully explainable, hence, the need to establish new boundaries that effectively include what serves as a natural park.

4. Results

4.1. GNSS Processing of Ground Control Points

The ground control points were processed using Trimble Business Center software, which enabled differential correction and baseline computation between the long-occupation point and the RBMC reference stations (RJNI and ONRJ). The point data are briefly summarized below (

Table 1. Geodetic coordinates of control points SIRGAS2000.

Point	Latitude	Longitude	Geometric Altitude (m)
P1	−22°46${}^{\prime }$00.50266${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$45.18207${}^{\prime }$${}^{\prime }$	−4.4275
P2	−22°46${}^{\prime }$08.47985${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$40.28453${}^{\prime }$${}^{\prime }$	−3.7033
P3	−22°46${}^{\prime }$02.72132${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$37.49554${}^{\prime }$${}^{\prime }$	−2.1091
P4	−22°45${}^{\prime }$58.18746${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$34.12064${}^{\prime }$${}^{\prime }$	1.6023
P5	−22°45${}^{\prime }$56.75228${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$21.30953${}^{\prime }$${}^{\prime }$	−1.5859
P6	−22°46${}^{\prime }$03.65796${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$18.60927${}^{\prime }$${}^{\prime }$	−4.0715
P7	−22°46${}^{\prime }$03.15952${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$44.97066${}^{\prime }$${}^{\prime }$	−4.4842
P8	−22°46${}^{\prime }$09.71985${}^{\prime }$${}^{\prime }$	−43°06${}^{\prime }$33.96760${}^{\prime }$${}^{\prime }$	−4.0419

), including latitude, longitude, and geometric altitude.

According to the conversion factors from geometric to normal altitudes, the HGEOHNOR2020 altitude conversion model, developed by Instituto Brasileiro de Geografia e Estatística (IBGE), was applied to correct the altitude differences [78] obtained at the SAT-RN stations.

$$H_N=h-\eta$$

(1)

where:

$H_N$ is the normal altitude;

$\eta$ is the conversion factor;

h is the geometric altitude.

The GNSS-processing results indicated that the positioning errors were within the precision limits required for the project.

Table 2. UTM coordinates and normal altitudes for points 1 through 8.

Point	Easting (m)	Northing (m)	Geometric Altitude	hgeoHNOR2020 Conversion Factor	Normal Altitude
P1	693,784.091	7,481,058.846	−4.327	−6.110	1.773
P2	693,920.668	7,480,811.676	−3.596	−6.110	2.514
P3	694,002.252	7,480,987.789	−2.945	−6.110	3.165
P4	694,100.546	7,481,126.040	1.735	−6.110	7.845
P5	694,466.578	7,481,165.520	−1.460	−6.110	4.650
P6	694,540.890	7,480,952.087	−3.991	−6.110	2.119
P7	693,789.080	7,480,977.043	−4.381	−6.100	1.719
P8	694,100.377	7,480,771.238	−3.939	−6.110	2.171

summarizes the final UTM coordinates and the approximate normal orthometric altitudes converted using the IBGE’s hgeoHNOR2020 altitude conversion model.

The adjustment error analysis (

Table 3. Errors for points 1 through 8.

Point	RMSE (m)	Easting Error (m)	Northing Error (m)	Altitude Error (m)
P1	0.0276	0.0111	0.0100	0.0232
P2	0.0010	0.0060	0.0007	0.0015
P3	0.0048	0.0029	0.0034	0.0071
P4	0.0032	0.0020	0.0021	0.0048
P5	0.0032	0.0014	0.0019	0.0050
P6	0.0019	0.0011	0.0015	0.0027
P7	0.0025	0.0018	0.0012	0.0037
P8	0.0023	0.0014	0.0016	0.0034

) reveals that no control point exceeds a 3D root-mean-square error (RMSE) of 5 cm, with most points exhibiting significantly smaller errors. Under Brazilian land cadastre regulations, which mandate a planimetric RMSE limit of 8 cm per vertex, these results are well within compliance. Notably, when height errors are excluded, the planimetric RMSE further decreases, reinforcing the high accuracy degree of the positional survey.

4.2. Photogrammetric Bundle Block Adjustment

The generated dense point cloud (Figure 13) contained 360,347 million points, completely covering the survey area with sufficient density to capture features appropriate for the target scale, as evidenced by their clear visibility in the point cloud. This level of detail supports decision making for the study’s objectives and provides strategic support for urban infrastructure planning.

The digital surface model (Figure 14) shows a high degree of detail, accurately reflecting elevation variations throughout the park. This product is essential for complementary analyses, including the generation of a digital terrain model (DTM), and contour lines.

Using the images and the DSM, an orthomosaic comprising the park and Morro do Vigário was generated with a ground-sampling distance (GSD) of 2.49 centimeters/pixel (Figure 15), demonstrating a high degree of geometric fidelity and meeting the target scale of 1:1000 as planned. This resolution enables the clear identification of detailed features requiring finer resolutions than previous datasets, including drainage culverts, sidewalks, stairways, and other small-scale infrastructure elements.

The integration of ground control points (GCPs) significantly improved the geometric accuracy. The total root-mean-square error (RMSE) relative to the control points was 0.21 cm (

Table 4. RMSE relative to control points.

E Error (cm)	N Error (cm)	h Error (cm)	Planimetric Error (cm)	Total Error (cm)
0.172092	0.130235	0.0124439	0.215817	0.216175

), while the checkpoints (not used in the adjustment) showed an RMSE of 4.64 cm (

Table 5. RMSE relative to checkpoints.

E Error (cm)	N Error (cm)	h Error (cm)	Planimetric Error (cm)	Total Error (cm)
2.72059	1.49499	3.4453	3.10429	4.63753

).

The photogrammetric method proved to be effective, with image overlaps ensuring precise alignment and high-quality outputs (orthomosaic, DSM), meeting 1:1000 scale requirements for cadastral applications. Ground control points (GCPs) enhanced the accuracy, though dense vegetation posed challenges for key-point adjustment. The vertical accuracy was determined based on the hgeoHNOR2020 model because of limitations in the local geodetic network. However, this could be enhanced through the implementation of permanent GNSS stations combined with geometric leveling—currently unavailable on the island because of the complexity of conducting such surveys.

4.3. Orthophoto Maps

The 1:1000-scale orthophoto maps were generated through rigorous photogrammetric processing and corrected using a network of ground control points (GCPs) to achieve centimeter-level geometric accuracy. As shown in Figure 15, these products demonstrate a high degree of spatial resolution (<2.5 cm GSD) and minimal distortion, enabling the precise visualization of both natural and anthropogenic features critical for cadastral applications. Figure 16 presents the complete orthomosaic of Darke de Mattos Natural Park, with clearly delineated physical boundaries following visible barriers, such as walls and topographic features. The companion orthophoto in Figure 17 covers the adjacent Morro do Vigário area, providing the baseline geodata for evaluating potential expansion scenarios discussed in subsequent sections.

4.4. Vector Data Layers and Topographic Map of Darke de Mattos Natural Park

The vector cartographic base was developed through the digitization of features from the orthorectified imagery, achieving positional accuracy compliant with 1:1000-scale requirements. As illustrated in Figure 18, this comprehensive dataset includes (1) anthropogenic features, such as buildings and infrastructure; (2) natural features, including vegetation boundaries; (3) topographic elements represented by 1-meter-interval contours; and (4) administrative boundaries. The dataset employs the UTM Zone 23S projection (SIRGAS 2000 datum) and may be readily integrated within geographical information systems (GISs).

This vector database served as the foundation for generating the official 1:1000 topographic map (Figure 19), which combines the geometric precision of the orthophoto with the analytical value of vector data layers. The map meets all the technical specifications for cadastral applications, providing an authoritative reference for resolving land tenure issues within the park boundaries. Its detailed representation of the terrain morphology and built environment support diverse applications ranging from conservation planning to infrastructure development while establishing a baseline for the future monitoring of landscape changes.

4.5. Proposed Scenarios for the New Parcel Integrating Morro do Vigário into Darke de Mattos Natural Park

This section presents four potential scenarios for the parceling of Morro do Vigário, along with their characteristics and the pros and cons of each regarding implementation impacts.

4.5.1. Methodological Proposal 1: Disconnected Parcel Excluding the Favela Area

The first proposal establishes a preservation area, excluding the currently occupied favela in Morro do Vigário, protecting both the community’s integrity and the remaining Atlantic forest. With a total area of 66,566.13 m² (6.65 hectares) and perimeter of 1552.40 m, this parcel was carefully delineated to circumvent urban occupation while preserving existing ecosystems. Fifty-eight vertices were used to define its boundaries, creating a shape that respects the area’s social characteristics (Figure 20 and Figure 21).

This approach aims to preserve natural environments by limiting favela expansion into forested areas, protecting local biodiversity, reducing deforestation risks, and maintaining ecological balance. Excluding the favela avoids interventions that might cause displacement or social conflict. However, it requires special monitoring to prevent further irregular expansions in Morro do Vigário.

The disconnected configuration from Darke de Mattos Natural Park presents management challenges, potentially hindering territorial integration and continuous ecological corridors. Without measures to improve administrative efficiency, this approach might represent inefficient public resource allocation. The disconnection also incurs additional maintenance costs.

4.5.2. Methodological Proposal 2: Disconnected Parcel Including the Favela Area

The second proposal includes the favela area but aims for the complete removal of the existing occupation. It covers 88,167.82 m² (8.81 hectares), with a 1636.50 m perimeter delineated using 76 vertices for a precise boundary definition (Figure 22 and Figure 23).

This approach seeks to fully restore the occupied area by removing irregular constructions and human activities impacting local ecosystems. It would restore the Atlantic forest and prevent future disorganized urbanization, including the favela, and allows for a controlled transition, integrating environmental recovery with social readjustment.

Although offering significant conservation benefits, this proposal faces substantial socioeconomic challenges. Resident relocation requires sensitive handling, ensuring adequate nearby resettlement with basic infrastructure, public transport, and urban services. The complex eviction and environmental restoration processes demand considerable financial and institutional resources.

The disconnection from Darke de Mattos remains problematic for effective administration and biodiversity conservation.

4.5.3. Methodological Proposal 3: Park-Connected Parcel Excluding the Favela Area

This proposal integrates the parcel with Darke de Mattos PNM while excluding the favela. It covers 66,697.33 m² (6.66 hectares), with a 1581.99 m perimeter defined by 58 vertices (Figure 24 and Figure 25).

This configuration strengthens physical and ecological connectivity, creating continuous Atlantic forest corridors that benefit biodiversity and environmental balance. Excluding the favela avoids direct community interventions, minimizing social conflicts. However, it requires monitoring to prevent informal settlement expansion.

A significant drawback is the required closure of Luís de Andrade Street, forcing southern residents to detour around Morro do Vigário to access western island areas and park entrances. An alternative solution proposes transforming the road segment into a public easement with elevated ecological corridors (footbridges or aerial walkways), maintaining both ecological connectivity and public access.

4.5.4. Methodological Proposal 4: Park-Connected Parcel Including the Favela Area

In the final proposal, the parcel is connected directly with Darke de Mattos PNM while including the favela area for complete environmental restoration. It encompasses 88,299.02 m² (8.83 hectares), with a 1666.09 m perimeter defined by 76 vertices (Figure 26 and Figure 27).

The complete occupation removal would restore Atlantic forest ecosystems, reverse environmental damage, and strengthen ecological connectivity. However, the social impact is substantial, requiring careful resident relocation with adequate housing, infrastructure, and socioeconomic integration opportunities to minimize conflicts and human rights violations.

As in Proposal 3, implementation would close Luís de Andrade Street, disrupting local mobility. The same aerial corridor alternative applies, converting the road segment into a public easement with raised walkways to maintain ecological and transport connectivity.

5. Discussion

5.1. Affordability and Scientific Significance of this Methodology

This methodology represents a significant advancement in cost-effective geospatial monitoring for natural parks, demonstrating that cadastral-grade precision can be achieved through the optimized integration of accessible technologies, such as an entry-level remotely piloted aircraft system (RPAS) paired with high-precision GNSS and a carefully designed ground control point (GCP) network. With total equipment costs under USD 30,000, this approach provides conservation authorities with an affordable solution for autonomous boundary management, achieving centimeter-level accuracy that rivals those of traditional survey methods costing many times more. The importance of this work lies in validating the precision of photogrammetric principles, showing that a suitable methodology, in particular, optimized flight planning and GCP distribution (as in [79,80] but with a more modest number of GGPs employed), can compensate for the limitations of the equipment. This makes high-precision mapping accessible to protected areas with limited resources, thus enabling environmental planning and cadastral reform [81,82].

The photogrammetric workflow proved to be exceptionally robust, with 80% longitudinal and 70% lateral image overlaps generating consistent point clouds, while GCP-based corrections reduced distortions to sub-centimeter levels (RMSE < 5 cm). Unlike comparable studies in UAV photogrammetry [83,84], which achieved high degrees of precision (${\displaystyle \le }$8 cm RMSE) yet fell short of 1:1000-scale requirements, the present methodology demonstrates geometric robustness through strategic GCP deployment, successfully meeting cadastral-scale accuracy standards. This advancement confirms this approach’s feasibility for both cadastral applications and environmental governance purposes.

Notably, the entire survey could be completed within days and repeated quarterly, enabling frequent monitoring, a critical capability for detecting illegal encroachments and vegetation changes in protected areas. The rapid deployability and standardized workflow make this approach particularly valuable for emergency response situations and routine monitoring alike.

Although this methodology shows remarkable cost-effectiveness, certain limitations were identified that point to future research directions. Dense vegetation areas presented challenges for key-point matching, suggesting potential synergies with seasonal surveys or LiDAR integration. The vertical accuracy relied on the hgeoHNOR2020 model because of local geodetic network limitations, though this could be improved with permanent GNSS stations.

These constraints notwithstanding, this approach has been successfully validated for multiple environmental management applications, including precise boundary demarcation, illegal construction detection, vegetation change analysis, and infrastructure planning—challenges raised by several authors—under similar circumstances [85,86,87]. The methodology proposed in this article, therefore, may be replicated in other conservation contexts. This work establishes a new benchmark for affordable precision mapping in land governance, democratizing access to cadastral-quality geodata for protected-area management.

5.2. Determination of the Darke de Mattos Natural Park’s Limits

The current land records for Darke de Mattos Natural Park lack legal validity because of the absence of precisely demarcated boundaries in the cadastral system. This legal ambiguity creates substantial governance challenges, directly impeding conservation initiatives, maintenance operations, and critical infrastructure projects essential for proper park management and environmental protection.

The newly developed topographic map and geodatabase provide an authoritative, legally defensible foundation for resolving these longstanding disputes. With centimeter-level accuracy and full compliance with 1:1000 cadastral standards, these documents constitute irrefutable evidence of the park’s true physical boundaries. Using such documents (which were submitted to the Municipal Department of the Environment) authorities now have a couple of choices: either submit a formal boundary delineation proposal to the municipal council for legislative approval or issue an executive decree through the Municipal Environmental Secretariat to establish definitive park boundaries.

As opposed to other scenarios, where lower precision rates could be tolerated [88,89,90,91], Darke de Mattos is, essentially, an urban park and must meet higher accuracy levels because of its location. This precise geodatabase managed to reach levels of accuracy comparable to those of lengthy topographic surveys, which would demand much more time and effort [92]. This product provides legal certainty for all land-use planning and enforcement activities, enables effective municipal control over unauthorized encroachments, and creates the necessary framework for targeted conservation investments.

Therefore, these georeferenced products provide the missing legal and technical foundation required to transform Darke de Mattos Natural Park from a conceptual protected area to a properly governed and managed conservation unit. The time-sensitive implementation of these boundaries represents both a legal necessity and a strategic opportunity to secure the park’s ecological future while protecting municipal interests.

5.3. Parcelling Scenarios and Further Expansion of Darke de Mattos to Encompass Morro do Vigário

A total of four different land-parcelling scenarios were suggested—each one with social and environmental implications. These successfully reconcile environmental conservation objectives with existing socio-spatial dynamics through three key innovations: (1) ecologically optimized boundary delineation, (2) socially sensitive zoning approaches, and (3) legally compliant cadastral documentation. As with the geospatial database and topographic map, these parcelling scenarios were also submitted to the Municipal Department of the Environment for further action and the eventual formal integration of Morro do Vigário with Darke de Mattos Natural Park through a legally binding ordinance or decree.

Our parceling proposals present distinct strategies for preserving Atlantic forest remnants while considering social dynamics and connectivity with Darke de Mattos Park. Favela-exclusive alternatives prioritize ecosystem protection without direct urban interference, minimizing social conflicts. Although disconnected parcels face ecological integration challenges, continuous configurations enhance biodiversity corridors. Both approaches require complementary land-use controls and monitoring regimes for long-term effectiveness.

The connectivity scenarios involving potential public right-of-way modifications demand careful strategic planning because of mobility impacts. The aerial footbridge alternative emerges as a feasible solution, balancing ecological connectivity with maintained community access. Favela-inclusive proposals, though offering greater ecological restoration potential through complete clearance, present substantial socioeconomic challenges, including resident relocation and implementation costs that require sensitive handling.

In comparative terms, Proposal 1 avoids social conflicts by preserving the existing favela and has low immediate costs because no relocation is required. In a certain way, it protects the remaining Atlantic forest from further encroachment. However, it is disconnected from Darke de Mattos Park, reducing ecological continuity, requires long-term monitoring to prevent favela expansion, and is potentially inefficient in resource allocation because of the fragmented management of two non-adjacent parcels. Proposal 2 maximizes ecological restoration by removing all human occupation and effectively prevents future urbanization in the area, at very high social and financial costs because of the relocation of the informal settlement and building of proper housing. Also, it risks violating basic human rights if not properly managed. And, as in Proposal 1, it is still disconnected from the park, limiting biodiversity benefits. Proposal 3 enhances biodiversity through ecological corridors linked to the park, avoiding the displacement of the current residents, but may lead to road closure, disrupting local mobility, and costly alternatives, like footbridges. Also, because the local favela is retained, it requires vigilant monitoring to prevent further informal settlements. Finally, Proposal 4 presents the highest ecological payoff of all the scenarios by providing for the restoration of previously inhabited areas plus bioconnectivity. As in Proposal 2, it eliminates the long-term risks of urban expansion into the forest. Nevertheless, it is the most expensive and socially disruptive option, with a rather complex implementation—which involves the relocation of the favela residents and road infrastructural changes.

Therefore, Proposals 1 and 3 are the ones with minimal social impacts. On the other hand, Proposals 2 and 4 provide for maximal ecological restoration. Proposal 3 stands out as a balanced approach, which keeps the existing favela (although special attention must be paid to prevent its further expansion), while creating pathways that connect both parcels, and creates continuous corridors that benefit both biodiversity and environmental balance. Proposal 4 is the most ambitious of all the options. It demands significant resources not to violate human rights (thus providing appropriate resettlement to the favela residents). Yet, by restoring biodiversity to the entirety of Morro do Vigário and effectively connecting it to Darke de Mattos Park, it delivers the greatest environmental benefits. A summary of the four proposals and their pros and cons may be found in

Table 6. Pros and cons of the four parcelling scenarios.

Criterion	Proposal 1 (Disconnected, Excluding the Favela)	Proposal 2 (Disconnected, Including the Favela)	Proposal 3 (Connected, Excluding the Favela)	Proposal 4 (Connected, Including the Favela)
Area Size	6.65 ha	8.81 ha	6.66 ha	8.83 ha
Perimeter	1552.40 m	1636.50 m	1581.99 m	1666.09 m
Social Impact	Minimal (avoids displacement)	High (requires relocation)	Minimal (avoids displacement)	Very High (large-scale relocation)
Ecological Benefits	Moderate (isolated forest protection)	High (full restoration potential)	High (connected corridors)	Very High (restoration + connectivity)
Implementation Cost	Low (monitoring only)	Very High (relocation + restoration)	Moderate (road closure solutions)	Very High (relocation + infrastructure)
Management Complexity	High (disconnected from park)	High (disconnected + social challenges)	Moderate (requires coordination)	Very High (integration + social policies)
Mobility Impact	None	None	High (road closure or footbridge)	High (road closure or footbridge)

.

Rio de Janeiro is a singular metropolis, where remnants of native Atlantic forest persist amid dense urban occupation. As one of Latin America’s largest cities, its planning challenges are often perceived as ungovernable because of competing social, environmental, and institutional pressures. However, this study adopts a dynamic and pluralistic perspective on planning in the public sphere: a view aligned with [93]’s conception of governance as being nonlinear and context-dependent, thus rejecting one-size-fits-all solutions and, instead, emphasizing locally adaptive strategies that explicitly consider who is governed and what priorities exist [27]. The four parcelling schemes presented herein reflect this philosophy, offering scenario-based approaches to mediate between environmental conservation and social equity. By incrementally addressing disparities—whether socioeconomic or environmentally driven—these proposals demonstrate how targeted planning interventions can reconcile competing demands while advancing systemic resilience.

It is also worth noting that preservation extends beyond biodiversity maintenance. Well-defined legal frameworks for conservation units help to sustain urban livability by balancing built environments with natural forests. Even when implemented incrementally through fit-for-purpose approaches, land cadastres remain effective tools for guiding urban expansion. This organized spatial governance helps cities to achieve safer equilibria between public green spaces and developed areas while accommodating continued urban growth [17].

The presence of an integrated natural park—protected, yet enhancing the island’s scenic beauty—represents a public incentive that may elicit diverse responses from local residents. Although incentive plans require context-specific analysis rather than universal application, the four proposed scenarios could produce outcomes significantly different from initial expectations (see [94,95,96]). For instance, beyond the economic consequences of relocating the favela in Morro do Vigário, neighborhood improvements (whether through removal or redevelopment) might increase land values and restore the island’s historical role as a holiday destination. However, this could also foster resident dependency on public works while limiting opportunities for community-led park preservation and maintenance. The relocation process itself presents substantial challenges: Given the island’s limited size, any resettlement must occur within its boundaries, requiring the careful repurposing of currently inhabited areas without resorting to vertical development that would compromise the landscape and violate zoning regulations. In all the proposed scenarios, the park’s expansion should avoid being perceived as a cultural fix [96] that artificially reshapes residents’ identities. Instead, planning must adopt a people-centered approach, actively incorporating local perspectives.

Fundamentally, all four scenarios would likely generate island-wide impacts, potentially triggering varied behavioral responses and expectations among the residents. Their implementation should, therefore, incorporate behavioral theory frameworks (such as the approach in [97]) to systematically assess the residents’ perspectives regarding the park. This would enable the identification of psychological and behavioral factors critical for selecting the optimal scenario—one that ensures sustained public support, the collective maintenance of park amenities, and minimal social disruption.

The longer-term sustainability of the park and its proposed expansion would be greatly strengthened by anticipating market effects and distributive outcomes. As demonstrated in [98], urban green space interventions often trigger complex value chain reactions: not only increasing adjacent property values but also potentially accelerating gentrification pressures that could displace existing communities. Future research must seek to estimate the park’s capitalization in local real estate markets, using hedonic pricing frameworks to understand how qualitative attributes affect housing prices [99] and estimate their impacts among different socioeconomic groups [100], as well as the eventual shifts in park utilization patterns and their impacts on the housing market.

Furthermore, insights from behavioral economics [97] highlight how market dynamics are deeply intertwined with the residents’ senses of ownership and fairness. When distributive outcomes disproportionately burden long-term residents, such as through rising living costs without commensurate benefits, trust erodes, undermining both voluntary maintenance efforts and broader political backing for the project. To mitigate this, well-designed value-capture mechanisms can realign incentives and redistribute gains equitably, for instance, through targeted tourist taxes to offset localized inflationary pressures, progressive levies on underutilized properties (to discourage speculation), and tax-increment financing (TIF) to reinvest windfall gains into community programs. Such measures not only enhance the project’s financial feasibility but also strengthen its social license by ensuring that residents perceive tangible benefits from the park’s economic spillovers. Strategic and proactive affordability safeguards could, thus, serve as force multipliers for sustainability outcomes.

5.4. Darke de Mattos Park’s Cadastral Survey Within the Framework of Fit-for-Purpose Land Administration

Land administration has evolved from a focus on recording ownership, value, and land use [101] to an enabling infrastructure for sustainable development, structured around four core functions: land tenure, value, use, and development [102]. Although developed nations benefit from secure tenure systems, in the developing world, there is a generalized lack in terms of affordable land rights registration, which disproportionately affects the poor and vulnerable.

In response, modern land administration systems now incorporate informal and social tenure models, supported by frameworks like the continuum of land rights and the social tenure domain model (STDM). The fit-for-purpose land administration (FFPLA) approach, introduced in 2014, operationalizes these priorities through adaptable spatial, legal, and institutional frameworks to secure land rights at scale. This shift aligns with global agendas, such as the Sustainable Development Goals (SDGs) [102,103], which emphasize poverty reduction, food security, and gender equity, alongside technological advancements, enabling cost-effective mapping [104].

A fit-for-purpose land administration (FFPLA) cadastre does not require a high degree of initial precision but, instead, prioritizes inclusivity, scalability, and adaptability [105]. This approach often begins with participatory geospatial technologies—such as handheld GNSS devices, mobile mapping applications, open-source software (e.g., QGIS), and collaborative mapping platforms—enabling broad stakeholder engagement, including non-state actors. Over time, boundaries and parcels can be incrementally refined to higher precision levels while remaining compliant with legal frameworks.

In this study, we demonstrated that even entry-level equipment can achieve precision compatible with regulatory standards. Our methodology employed a robust orthoimage adjustment process anchored to surveyed control points, ensuring that virtual vertices [63] met high-level accuracy criteria ($\sigma$ < 0.05 m). Although the orthoimage met all the project’s requirements with satisfactory precision, dense vegetation posed challenges for identifying artificial boundary markers. We addressed this through the strategic extrapolation of visible features and the implementation of 5 m interior buffers in uncertain areas, ensuring boundary consistency while maintaining ecological integrity.

This methodology offers a transferable, cost-effective framework for upgrading non-certified parcels initially mapped via lower-precision FFPLA methods. Its simplicity and affordability make it feasible for systematic integration into FFPLA workflows, particularly for incremental cadastral updates.

5.5. Future Studies and Improvements

To improve the practical adoption of this methodology in future applications, we recommend the physical monumentation of boundaries where feasible. Although the parcels in this study were classified as non-certified because of field accessibility limitations that prevented monumentation, establishing physical markers would enable official certification and strengthen the legal recognition of property boundaries.

As future steps, geospatial products could be further utilized to generate high-resolution land use–land cover (LULC) maps through advanced machine-learning-based classification techniques, such as convolutional neural networks (CNNs) or random-forest algorithms. These classifications can systematically quantify tree coverage, distinguishing between various vegetation classes [106]. Such LULC maps would not only enhance urban planning and ecosystem management but also support the valuation of urban green spaces [107] in terms of carbon sequestration, biodiversity conservation, and microclimate regulation.

Future research could also expand to analyze the built environment surrounding the park, integrating emerging frameworks, such as the 3D cadastre and land administration domain model (LADM) [108,109,110]. These approaches incorporate three-dimensional data into land registries, urban planning, and governance—critical considerations given the park’s unique features, including a heliport, elevated terrain, and dense urban context. By adopting 3D land administration models, studies can better address spatial complexities and support sustainable development in multifunctional urban spaces.

6. Conclusions

This study successfully established a physical parcel for Darke de Mattos Natural Park and four different scenarios for an additional parcel, integrating it into Morro do Vigário and demonstrating an effective approach for managing the remaining Atlantic forest fragments threatened by urban expansion. Our systematic analysis confirms the technical feasibility of this conservation strategy, while revealing several critical challenges that warrant consideration for future implementations.

The absence of updated cadastral records emerged as a significant constraint, necessitating the near-complete reconstruction of parcel boundaries from first principles. Our high-resolution orthoimage (2.49 cm GSD) proved to be instrumental in overcoming this limitation, enabling the precise delineation of boundaries and generation of comprehensive descriptive reports, including coordinate tables, areas, perimeters, and vertex positions. Legal data inaccessibility further complicated the identification of adjacent landowners and their property boundaries.

This methodology stood out through its use of remotely piloted aircraft systems (RPAs) integrated with high-precision GNSS, complemented by a dense and reliable network of control points. This integration was crucial for achieving results meeting the required precision standards. Furthermore, this method showed excellent cost-effectiveness, establishing itself as a practical and feasible solution for cadastral projects with significant applications in urban engineering.

These results underscore four critical requirements for sustainable implementation as follows:

• The establishment of permanent geodetic control points;
• Quarterly monitoring through repeat UAV surveys;
• The formal adoption of boundaries through municipal decrees;
• Integrated land-use policies addressing both conservation and community needs.

Additionally, this study’s four parcelling scenarios balance conservation and equity through incremental, context-sensitive interventions. These findings establish a robust foundation for the integrated management of Morro do Vigário’s forest remnant. Our analysis demonstrates that environmental protection can be reconciled with social preservation, while highlighting the urgent need for improved cadastral records and integrated policies to ensure both territorial sustainability and community integrity, a concern not limited to Brazil, but universal [111,112]. The methodology developed herein provides a transferable framework for similar conservation challenges in other pockets of natural areas in urban environments.

Finally, park expansion must avoid top-down “cultural fixes” by centering local voices and anticipating behavioral responses (for example, via hedonic pricing and behavioral economics frameworks). Market effects, such as gentrification risks, will necessitate equitable value-capture tools to redistribute benefits and sustain community trust. Ultimately, integrating technical precision with participatory planning can reconcile ecological resilience and social equity in contested urban landscapes.

Future research could, therefore, seek to estimate such impacts and focus on the longitudinal monitoring of implementation outcomes and socioeconomic impacts to further refine these models for application in similar urban-adjacent conservation areas. It could also leverage emerging trends in geospatial technologies, aiming to generate LULC maps and integrating the three-dimensional components into land cadastres, thus enhancing urban ecosystem valuation and adaptive governance.