# Numbers on Thematic Maps: Helpful Simplicity or Too Raw to Be Useful for Map Reading?

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Numbers on Maps as an Approach for Cartographic Presentation

#### 2.1. The Functions of Numbers on Maps

#### 2.2. Numbers on Maps as a Form of Content Redundancy

- RQ 1: Are numbers used as an independent method on a single-variable map just as effective as traditional methods of cartographic presentation?
- RQ 2: Is it useful to use numbers on a map to repeat information already presented on the map using other visual variables?
- RQ 3: Are numbers useful as one of the elements on a multi-variable map?

## 3. Materials and Methods

#### 3.1. Study Material

- A map with only numbers or proportional symbols expressing quantitative information (numbers or proportional symbols employed as an independent cartographic presentation method, a simple map showing one phenomenon—simple single-variable map;
- A map with numbers or proportional symbols that duplicate the information presented on a choropleth map (a map showing one phenomenon—redundant single-variable map);
- A map with numbers or proportional symbols presented on a choropleth base map, with each method showing a different phenomenon (two-variable map).

#### 3.2. Participants

#### 3.3. Methods, Tasks, and Procedures

#### 3.4. Data Analysis

## 4. Results

#### 4.1. Comparing the Effectiveness of Presentation Methods

#### 4.2. Comparing the Answer Times

#### 4.3. Method Choice and Assessment of the Map’s Difficulty

## 5. Discussion

**RQ**

**1:**

**RQ**

**2:**

**RQ**

**3:**

## 6. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**Examples of the use of numbers on small-scale thematic maps: (

**A**) even-sized numbers on a map showing the values of a given phenomenon (single-variable), (

**B**) even-sized numbers with proportional symbols (content redundancy), (

**C**) proportional numbers with a choropleth map (content redundancy), and (

**D**) presentation of temperature and wind speed on a weather map (multi-variable map).

**Figure 2.**Fragments of map types used in the study. A–C: Simple single-variable maps presenting one data set by: (

**A**) even-sized numbers, later abbreviated as “N”, (

**B**) proportional numbers “PN”, (

**C**) proportional symbols “PS”. D–F: (

**D**) Redundant single-variable maps also presenting one-data set by choropleth map and also by: even-sized numbers “N”, (

**E**) proportional numbers “PN”, (

**F**) proportional symbols “PS”. G–I: (

**G**) Two-variable maps presenting two data sets using choropleth map and: even-sized numbers “N”, (

**H**) proportional numbers “PN”, (

**I**) proportional symbols “PS”.

**Figure 3.**The main window of the application used by the study participants. The map title and legend were on the left side of the window, while the buttons with tools for identifying points and drawing polygons were in the upper right corner of the map window. On the right was a task panel in which the participants provided their answers.

**Figure 5.**The proportion of correct answers, taking into account the data presentation methods used on maps in tasks T1–T9.

**Figure 7.**Comparison of the methods declared to be the most helpful in answering the individual tasks.

Task | Group 1 | Group 2 | Group 3 | Maps and Methods |
---|---|---|---|---|

T1 | N | PN | PS | SIMPLE SINGLE-VARIABLE MAP1 data set presented by N/PN/PS |

T2 | PN | PS | N | |

T3 | PS | N | PN | |

T4 | PN | PS | N | REDUNDANT SINGLE-VARIABLE MAP1 data set presented by N/PN/PS and by choropleth map |

T5 | PS | N | PN | |

T6 | N | PN | PS | |

T7 | PS | N | PN | TWO-VARIABLE MAP2 data sets: 1st data set presented by N/PN/PS, 2nd data set presented by a choropleth map |

T8 | N | PN | PS | |

T9 | PN | PS | N |

Type of Map | Task Number | Task | Possible Answer |
---|---|---|---|

SIMPLE SINGLE-VARIABLE MAP | T1:INDICATE MORE THAN | A region that offers accommodation in 66 accommodation facilities has been marked on the map. Use the tools in the green bar to indicate all regions that have more accommodation facilities. | Open question |

SIMPLE SINGLE-VARIABLE MAP | T2:SUM & ORDER | There are three areas (marked A, B, and C) indicated on the map that present the length of cycle paths. Each of the areas consists of three regions. Order these areas in terms of the length of their cycle paths, starting with the one in which the path length is shortest. | Open question |

SIMPLE SINGLE-VARIABLE MAP | T3:ESTIMATE HOW MANY TIMES | The map shows the number of registered taxis. Estimate how many times there are more taxis in region A than in region B. | Open question |

REDUNDANT SINGLE-VARIABLE MAP | T4:INDICATE ALL BETWEEN | The map shows the number of accommodation facilities. Use the tools in the green bar to indicate all regions with between 40 and 99 accommodation facilities. | Open question |

REDUNDANT SINGLE-VARIABLE MAP | T5:SUM & ORDER | The map shows the length of cycle paths in individual regions. Three areas (A, B, and C) have also been marked. Choose the area where the length of the cycle paths is shortest. | A, B, C |

REDUNDANT SINGLE-VARIABLE MAP | T6:INDICATE LESS THAN | The map shows the number of registered taxis. Indicate all the regions in which the number of registered vehicles does not exceed 10. | Open question |

TWO-VARIABLE MAP | T7:1st MORE & 2nd LESS | The map shows the number of accommodation facilities and related occupancy rates. Indicate 4 regions with a very high occupancy rate and a small number of accommodation facilities. | Open question |

TWO-VARIABLE MAP | T8:1st MOST & 2nd LEAST | The map shows the length of cycle paths and their congestion, i.e., how many kilometers of cycle paths there are per 1000 people. From the regions with the lowest congestion rates, choose the region in which the most cycle paths were built. | Open question |

TWO-VARIABLE MAP | T9:1st NO MORE & 2nd MOST | The map shows the number of registered taxis and their availability expressed as the number of taxis per 10,000 people. On the map, out of all regions in which the number of taxis do not exceed 500, choose 2 with the highest number of taxis per 10,000 people. | Open question |

Map Type | Task | Cramér’s V | p ^{1} | Pairwise Comparison | Cramér’s V | p |
---|---|---|---|---|---|---|

SIMPLE SINGLE-VARIABLE MAP | T1 | 0.271 | 0.000 *** | N—PN PN—PS N—PS | 0.123 0.321 0.206 | 0.050 * 0.000 *** 0.000 *** |

T2 | 0.235 | 0.000 *** | N—PN PN—PS N—PS | 0.179 0.112 0.288 | 0.000 *** 0.050 * 0.000 *** | |

T3 | 0.614 | 0.000 *** | N—PN PN—PS N—PS | 0.035 0.658 0.630 | 0.497 0.000 *** 0.000 *** | |

REDUNDANT SINGLE-VARIABLE MAP | T4 | 0.129 | 0.010 ** | N—PN PN—PS N—PS | 0.037 0.145 0.108 | 0.463 0.010 ** 0.050 * |

T5 | 0.160 | 0.001 *** | N—PN PN—PS N—PS | 0.079 0.190 0.114 | 0.122 0.000 *** 0.050 * | |

T6 | 0.097 | 0.064 | - | - | - | |

TWO-VARIABLE MAP | T7 | 0.085 | 0.138 | - | - | - |

T8 | 0.122 | 0.050 * | N—PN PN—PS N—PS | 0.007 0.135 0.128 | 0.895 0.010 ** 0.050 * | |

T9 | 0.185 | 0.000 *** | N—PN PN—PS N—PS | 0.044 0.170 0.213 | 0.391 0.001 *** 0.000 *** |

^{1}p—statistical significance, the probability of finding a given deviation from the null hypothesis, or a more extreme one, in a sample [41]. Significance scores: *** p < 0.001, ** p < 0.01, * p < 0.05.

Map Type | Task | Kruskal–Wallis H | p | Method | M (s) | SD | Post Hoc Groups | Bonfe-Rroni Post Hoc | p |
---|---|---|---|---|---|---|---|---|---|

SIMPLESINGLE-VARIABLEMAP | T1 | 0.515 | 0.773 | N PN PS | 49.19 46.87 46.88 | 23.23 24.57 23.66 | - | - | - |

T2 | 9.794 | 0.010 ** | N PN PS | 76.36 73.39 65.64 | 36.47 35.92 32.01 | N—PN PN—PS N—PS | 16.071 36.231 52.302 | 1.000 0.096 0.007 ** | |

T3 | 9.862 | 0.000 *** | N PN PS | 40.88 37.79 47.66 | 20.30 20.47 25.38 | N—PN PN—PS N—PS | 30.409 −75.428 −45.019 | 0.230 0.000 *** 0.023 * | |

REDUNDANT SINGLE-VARIABLEMAP | T4 | 4.254 | 0.119 | N PN PS | 36.19 36.44 39.48 | 15.20 14.25 18.36 | - | - | - |

T5 | 17.049 | 0.000 *** | N PN PS | 45.71 39.23 39.91 | 22.54 20.94 23.18 | N—PN PN—PS N—PS | 51.748 2.169 61.917 | 0.010 ** 1.000 0.001 *** | |

T6 | 11.439 | 0.010 ** | N PN PS | 23.82 25.32 27.72 | 9.77 9.95 12.91 | N—PN PN—PS N—PS | −22.512 −34.884 −57.396 | 0.549 0.127 0.010 ** | |

TWO-VARIABLE MAP | T7 | 4.408 | 0.110 | N PN PS | 42.16 40.16 37.61 | 21.38 21.71 19.34 | - | - | - |

T8 | 0.618 | 0.734 | N PN PS | 44.81 42.39 44.81 | 27.01 25.32 29.58 | - | - | - | |

T9 | 3.029 | 0.220 | N PN PS | 43.38 39.78 47.28 | 36.02 26.03 36.41 | - | - | - |

Map Type | Task | Cramér’s V | p | Pairwise Comparison | Cramér’s V | p |
---|---|---|---|---|---|---|

REDUNDANT SINGLE-VARIABLEMAP | T4 | 0.377 | 0.000 *** | N—PN PN—PS N—PS | 0.117 0.568 0.533 | 0.072 0.000 *** 0.000 *** |

T5 | 0.148 | 0.000 *** | N—PN PN—PS N—PS | 0.044 0.194 0.114 | 0.690 0.001 *** 0.000 *** | |

T6 | 0.291 | 0.000 *** | - | 0.208 0.504 0.315 | 0.000 *** 0.010 ** 0.050 * | |

TWO-VARIABLE MAP | T7 | 0.088 | 0.061 | - | - | - |

T8 | 0.083 | 0.089 | - | - | - | |

T9 | 0.061 | 0.358 | - | - | - |

Map Type | Task | Cramér’s V | p | Pairwise Comparison | Cramér’s V | p |
---|---|---|---|---|---|---|

SIMPLE SINGLE-VARIABLE MAP | T1 | 0.216 | 0.000 *** | N—PN PN—PS N—PS | 0.123 0.321 0.206 | 0.050 * 0.000 *** 0.000 *** |

T2 | 0.100 | 0.168 | - | - | - | |

T3 | 0.282 | 0.000 *** | N—PN PN—PS N—PS | 0.117 0.568 0.533 | 0.072 0.000 *** 0.000 *** | |

REDUNDANT SINGLE-VARIABLE MAP | T4 | 0.175 | 0.010 *** | N—PN PN—PS N—PS | 0.117 0.568 0.533 | 0.072 0.000 *** 0.000 *** |

T5 | 0.187 | 0.000 *** | N—PN PN—PS N—PS | 0.044 0.194 0.114 | 0.690 0.001 *** 0.000 *** | |

T6 | 0.091 | 0.300 | - | - | - | |

TWO-VARIABLE MAP | T7 | 0.080 | 0.500 | - | - | - |

T8 | 0.110 | 0.082 | - | - | - | |

T9 | 0.108 | 0.098 | - | - | - |

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**MDPI and ACS Style**

Korycka-Skorupa, J.; Gołębiowska, I.M. Numbers on Thematic Maps: Helpful Simplicity or Too Raw to Be Useful for Map Reading? *ISPRS Int. J. Geo-Inf.* **2020**, *9*, 415.
https://doi.org/10.3390/ijgi9070415

**AMA Style**

Korycka-Skorupa J, Gołębiowska IM. Numbers on Thematic Maps: Helpful Simplicity or Too Raw to Be Useful for Map Reading? *ISPRS International Journal of Geo-Information*. 2020; 9(7):415.
https://doi.org/10.3390/ijgi9070415

**Chicago/Turabian Style**

Korycka-Skorupa, Jolanta, and Izabela Małgorzata Gołębiowska. 2020. "Numbers on Thematic Maps: Helpful Simplicity or Too Raw to Be Useful for Map Reading?" *ISPRS International Journal of Geo-Information* 9, no. 7: 415.
https://doi.org/10.3390/ijgi9070415