For questions about heat maps, where a heat map is a graphical representation of geographic data, generally in the form of a coloured raster. Heat maps are used to highlight regions of higher than average data density.
A heat map is a graphical representation of data presented in the form a shaded matrix. In a geospatial context, a heat map represents the concentration of geographic data in the form of a coloured raster.
Heat maps make regions with higher than average concentrations of data (i.e., clusters) easy to identify. One means of creating a heat map is to interpolate point data to generate a continuous density surface.
Tools for generating heat maps are commonly available in GIS software.
Heat maps can be distinguished from choropleth maps in that their enumeration units are a regular grid while the enumeration units for choropleth maps are a set of non-arbitrary geographical enitities (e.g., administrative boundaries).
Heat maps can also be distinguished from maps showing "hot spots". While these types of maps are often similar in appearance, heat maps are a data visualization technique while hot spot maps are based on statisical analyses.