Geodemography or geodemographics is the study of the population and its characteristics, divided according to regions on a geographical basis and involves application of clustering techniques to group statistically similar neighborhood and areas.
The main source of data for this study is the census. However, periodicity of census data being high, other sources like country court judgements, property valuation and household council tax bands data are also used. 
In marketing, geodemographics or geodemographic segmentation refers to demographic consumer behavior and lifestyle data segmented by arbitrary geographic boundaries that are typically quite small. 
- mbaSKOOL, mbaskool.com/business-concepts/marketing-and-strategy-terms/7264-geodemographics.html, 2021.
- American Marketing Association, AMA Dictionary.