Heatmap

With heat maps you can determine regional aggregations of data values (so-called clustering). The regional aggregations are displayed on the map like mountains or like "hot zones".

The Heatmap analysis is particularly suitable for evaluating available locations as well as positioning new ones. Using the potential as a reference, then areas with particularly high cumulated data values (such as hot zones or mountain peaks) result as ideal locations.

Variants

In the site-specific variant of the heat maps, the map is displayed similarly to the images from thermal imaging cameras: Data peaks appear as especially "hot zones". In the area-related variant of the heat maps, the data peaks appear like mountains.

Creating a New Analysis

Drag and drop the data column for the heatmap in the control window data via drag and drop onto the map. In addition to the setting of the type of analysis and the allocation level, the analysis requires a selection of the analysis type: area-related or location-related - see variations and selection of the data basis.

Note: You can also insert your analysis via the menu bar Analyze. You get an analysis without predefined settings and value classes.

Determine the properties of the heat map

Properties refers to all settings for calculating and displaying the analysis. You can select or change certain columns of the previously defined table to control certain aspects of the display (e.g. the color). You can also access this settings dialog if you want to edit existing analyses.

If you have inserted the analysis via the main menu, the Heatmap is initially inserted after the Number of records (see Data column).

Selection of the data column

First select the column to be evaluated.

    • With a area-related analysis you can additionally determine aggregation of the data of the selected column. This specifies the rule how data are combined if several data are available for an area.
    • The Format option is only available for area-specific analyses. Normally, the formatting of the selected data column is also used for the analysis result; this is always the case for site-specific analyses. For certain aggregation procedures (for example, number of values), however, this formatting cannot be used meaningfully. You can define a new formatting here, which is used in legends for this analysis, for example.

    • Under Statistics you can display statistical information (e.g. number of data records, min., max.) for the selected column - click on the button in the field next to Statistics.

In the first section Color there are two display types available: Classified and Continuous. By default, a continuous color gradient of the heatmap is preselected, but you can edit it at any time. The properties are the same here, regardless of the type of analysis you have chosen - location-based or area-based.

How should the data be handled with increasing distance?

Before the analysis is displayed, a cumulated value is calculated for each area or pixel, which is then displayed as area shading.

This value results as sum of the base values of all areas in a certain circle (defined by the radius). Areas closer to this area are often more relevant than areas further away. Therefore, you can additionally specify whether the values of other areas should be weighted with the distance .

The following methods for taking into account the distance are offered: Complete, Linear descending or Square descending.

In the following figure you can see a comparison of the three options in a location based heat map. A radius of 50 km was set; the selected value for each location is the same. With the option complete the value for the coloring of the 50 km radius is completely included in the calculation. If two perimeters overlap, both values are used in full in the calculation. The option linearly descending calculates the values of a location with increasing distance linearly descending and with the third option squarely descending. As a result, the "hot zones" are smaller or sharper defined with the quadratically decreasing heat map, because the values decrease faster with increasing distance to the location.

Special effect

If you define the circle from which data are to be included in the calculation of the cumulated data values via kilometer in the map, the same environment is always taken into account for each pixel or for each brick regardless of the zoom. If, on the other hand, you define the circumference over centimeter on the leaf, the circumference to be taken into account changes depending on the zoom, because zooming changes the scale; as a result, the circumference to be taken into account becomes smaller and smaller as the zoom increases for given leaf centimeters. This often leads to a large cluster dissolving into many small sub-clusters as the zoom increases. In the heat map above, this would lead to the Rhine/Ruhr conurbation disintegrating into individual data peaks at the major cities of Cologne, Düsseldorf, Duisburg, Essen, Dortmund, etc.

How should colors and values be classified?

You can choose between a classified or continuous colored heatmap. The option Continuous offers you the convenience of a color gradient without specifying classes.

Determine the details of the analysis

In Details you define other (non-data-dependent) properties of the analysis.

Create tooltips for analysis

When crossing the colored areas on the map, you can display context-sensitive information about them.

Note: You can find out how to implement tooltips here.

The commands of the context menu

You can call up its context menu by right-clicking on the analysis in the control window contents. The context menu offers actions that can be performed on this analysis.