1. Choropleth map - a thematic map displaying the values of a selected attribute of two-dimensional objects, i.e. area objects formed by the division of a certain area. Object boundaries are predetermined, for example by administrative division, and the attribute values corresponding to objects are presented graphically, e.g. using colours or hatchings, usually taking into account the division of the range of variation of the attribute into classes. These values take a relative form - they include such measures as the number of people per 1 km2, use of artificial fertilisers per 1 km2, national income per 1 person.
The presentation of a selected thematic phenomenon using a choropleth map
Methods for creating intervals:
- Standard deviation – intervals determined by the average deviation from the arithmetic mean value of the phenomenon; interval limits are intervals from the arithmetic mean of the set in the form of the multiplicity of standard deviation;
- Equal intervals – intervals with equal range;
- Quantiles – equinumerous intervals, i.e. intervals with the same number of elements;
- Natural breaks – interval limits which in a natural way reflect breaks in their arrangement. This method is used for data with an even distribution;
- Individual intervals – interval values determined by the user for a given phenomena.
2. Diagram map – a thematic map displaying the variability of selected attributed of spatial objects, i.e. the theme using charts, e.g. bar charts or pie charts.
A presentation of selected thematic phenomenon using a simple diagram map
A presentation of selected thematic phenomenon using a pie structural diagram map
A presentation of selected thematic phenomenon using a bar structural diagram map
Sources of the definitions: http://www.ptip.org.pl – On-line geomatic lexicon, http://www.gisplay.pl/kartografia/metody-prezentacji-danych.html, author's own work.