Thematic Maps

Maprosoft Thematic Maps

Thematic maps are a great way to illustrate concepts that have a connection to geographic areas. Currently Maprosoft supports Choropleth Maps.

Theme Specification

Thematic maps are displayed by specifying a 'theme' parameter in the URL. The components of the theme parameter are as follows:

Component Description Mandatory? Default
key The key identifies the data that the theme is based upon. The key either a field within a Microformats or one of the keys in a KeyValue microformat. Yes N/A
featureTypeName The name of the type of data that the theme relates to. This must correspond to a feature type name. See the map data introduction page for an understanding of feature types. No If no feature type name is specified, the theme will be applied to all feature types available to the map.
min This identifies the minimum value that the data of the theme should have. This is used to determine the color to apply to each feature. No 0.0
max This identifies the maximum value that the data of the theme should have. This is used to determine the color to apply to each feature. No 100.0
colors This identifies the color gradient to use. The allowed values are blues, greens, greys, oranges, pinks, purples, reds, reds-greens and yellows. No The reds-greens color gradient is used if not specified.

Here is an example of a theme parameter to display parks with BBQs:


theme=key:bbqFacilities,featureTypeName:Parks
	

Color Gradients

The following illustrates the color gradients where the data with a value of min (specified by the theme) will have the color shown on the left, whilst data with a value of max (specified by the theme) will have the color shown on the right.

Name Colors
blues                                                            
greens                                                            
greys                                                            
oranges                                                            
pinks                                                            
purples                                                            
reds                                                            
reds-greens                                                            
yellows                                                            

Choropleth Maps

A choropleth map shows information that is averaged or summarised at a regional level such that the regions are colored according to the data. For example, the map at the top right of this page shows the parks with and without BBQs - parks colored red do not have BBQs whilst parks colored green do have BBQs.

Range Based Choropleth Maps

A range based choropleth map shows information based on data that has a range of values. The data (specified by the key of the theme) must be a floating point value. Each value is then converted to a color based on the theme's color gradient and comparison of the data value to the theme's min and max values.

Boolean Based Choropleth Maps

A boolean based choropleth map shows information based on data that is either true or false. False values will be rendered with the left-most color in the theme's color gradient. True values will be rendered with the right-most color in the theme's color gradient.