# How to best represent a geographical area as point

I need to check a relationship(?) between land surface temperature (LST) and total population census tract (shapefile) wise where i am trying to relate social factors (e.g. total population, female count, 16-60 aged people etc.) and utility (e.g. electricity, gas facility e.g.) to LST. Problem is LST is a regular square (pixel) surface but tract is irregular grid so i need to create point that represents each tracts and get LST value for those points. After all generating relationship.

So the question is how to represent an areal entity as a point more wisely?

N.B. I think geometric central point is not that much wise. Another one i am thinking of is generating random points as a percentage of tract area.

• There are many solutions. They depend on how you suppose the tract attributes might be associated with the LST, but generally you want to summarize the LST over each tract, such as by taking its mean, median, maximum, minimum, or whatever seems most appropriate and then relate one or more such summaries to the tract attributes. More practical and focused advice can be provided if you would edit this question to explain in more detail what you are attempting to do and what your model is. – whuber Apr 7 '16 at 16:49
• @whuber I have edited the question – SIslam Apr 9 '16 at 18:33
• Yes, I had noticed that--but your edits do not provide the kind of information I mentioned as being relevant and important. – whuber Apr 9 '16 at 18:47

Are shapefiles what you're referring to? Here's a quote from a Wiki article about them:

The shapefile format is a popular geospatial vector data format for geographic information system (GIS) software. It is developed and regulated by Esri as a (mostly) open specification for data interoperability among Esri and other GIS software products. The shapefile format can spatially describe vector features: points, lines, and polygons, representing, for example, water wells, rivers, and lakes. Each item usually has attributes that describe it, such as name or temperature.

https://en.wikipedia.org/wiki/Shapefile

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Here's a paper that may be close to what you're looking for by Elizabeth Roberto, Spatial Boundaries and the Local Context of Residential Segregation. Here's the abstract:

Spatial boundaries are a defining feature of a city’s social and spatial organization. Rivers, highways, and train tracks create excess distance between nearby locations and often mark social separation – they become dividing lines that are well known to residents. Qualitative studies are rich with insight about the local significance of boundaries, but they have been largely ignored in the quantitative segregation literature. I advance existing scholarship by integrating spatial boundaries into the way we measure residential segregation for city populations. I introduce a new method that measures the proximity of residential locations and the reach of local environments around each location using road distance. This is more realistic than straight line ("as the crow flies") distance, because it captures the connectivity of roads and the distance imposed by physical boundaries...

https://pdfs.semanticscholar.org/0cb0/4b5d06078f50c0d6c561e67b4543f26c91ea.pdf

• Yes.. I mean shapefile. but is it answeer? – SIslam Apr 7 '16 at 13:18
• If you have GIS software and your LST information has lat-long coordinates, then you can map your data into that software. At that point, statistical analysis of your information in relation to its surrounding geography is possible. I may be uncertain as to what you're asking though...are you asking how to create the points on an "irregular grid?" In other words, what methodology would you use to accomplish this? – Mike Hunter Apr 7 '16 at 13:41