From Wikipedia,

A heat map is a graphical representation of data where the individual values contained in a matrix are represented as colors.

Apparently, a geographic heat map is only one kind, and this is the only kind relevant to me. Cartography is about geographic maps. In cartography, I often distinguish between topographic and thematic maps.

From Wikipedia,

A thematic map is a type of map or chart especially designed to show a particular theme connected with a specific geographic area.

In thematic cartography, we can at least distinguish between types of thematic maps: statistical, color, choropleth, isopleth, dasymetric, point-symbol, and so on.

How is a geographic heat map any different from a colored statistical thematic map?

  • 1
    Duplicate? gis.stackexchange.com/questions/70991/…
    – Mapperz
    Jan 15, 2014 at 18:46
  • 4
    @Mapperz It looks like a duplicate but I think not: many GIS people have adopted the term "heat map" in a loose sense that is far broader than the Wikipedia definition quoted here. The possible duplicate uses that vague broad sense and as such probably has no adequate answers to the present question.
    – whuber
    Jan 15, 2014 at 18:56
  • @whuber Hence flagged 'Duplicate?' and not implemented the hold on the question.
    – Mapperz
    Jan 15, 2014 at 18:59
  • I agree, in my experience, it seems to be a generic term used to refer to any sort of color-shaded isopleth, particularly if drawn with a two-shade color ramp. I figured the reasoning was related to the tool name in QGIS, much in the way Xerox became synonymous with photocopy.
    – TDavis
    Jan 15, 2014 at 19:03
  • 1
    +1 but original title much broader than question in body so edited to avoid the former being answered and the specific question overlooked.
    – PolyGeo
    Jan 15, 2014 at 20:42

1 Answer 1


I think of 'heat map' as more of a density map created from points. Symbology is usually on a color ramp as opposed to more discrete chloropleth style symbology. That may not be the official definition, but works for me.

  • In cartography, a density map created from points is termed a dot map. Maybe you refer to the type of source data? in which case it's a matter of assumptions about the geographic phenomenon being sampled and how to process the data. Choropleth maps do traditionally have discrete classes either out of necessity (simple technology) or by design (for generalization). Choropleth maps can, however, have a continuous classification scheme (color ramp).
    – Martin F
    Jan 15, 2014 at 20:57

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