Heat Maps (Kernel Density Estimation)

Short DescriptionHeat maps for urban health are visual representations that use color-coded gradients to depict variations in health-related indicators across different areas within a city.
DataPoint-based data
Suggested toolsGeodaQGIS
CategorySpatial Visualisation
VariableUnivariate

Overview


A heat map, also known as a density map, is a visualization technique that represents the density of point data by assigning colors to areas based on the frequency or intensity of the data points within those areas. It is commonly used to identify hotspots or areas of high activity within a geographic area.

KDE calculates a smooth estimate of the spatial density of point data by placing a kernel, typically a Gaussian function, at each data point and summing their contributions across the study area.

Applications in Urban Health


Tutorial


QGIS

Use the Heatmap/Kernel Density Estimation tool in the Processing Toolbox, specifying input point data and parameters such as kernel type, bandwidth, and output raster resolution.

external resources:

27.1.5. Interpolation — QGIS Documentation documentation
QGIS 3.28 documentation: 27.1.5. Interpolation
https://docs.qgis.org/3.28/en/docs/user_manual/processing_algs/qgis/interpolation.html#id15

Python

To create a heatmap using Plotly in Python, you can use the plotly.graph_objects module, which provides a Heatmap object for this purpose.

Heat map on a map (spatial heat map) in plotly
Build dynamic spatial heatmaps in Python with the density_mapbox function from plotly express. You will learn how to add heat maps over a map and how to customize the Mapbox styles and colors of the chart
https://python-charts.com/spatial/spatial-heatmap-plotly/