Select to view content in your preferred language

How Does Arcgis figure out which area of a map a point belongs to

295
1
04-01-2024 05:46 PM
DanAllenhtn
New Contributor II

How does the computer figure this out?  There must be a certain math involved,  no?

This was not taught in any school I ever attended.

DanAllenhtn_0-1712018846283.png

 

 

 

 

 

0 Kudos
1 Reply
ChristopherCounsell
MVP Regular Contributor

Vector data typically consists of:

  • Geometry (points, or points making up lines/polygons)
  • Attribute data (table where each geometry record has associated valeus)

You are showing a table. Taking a guess:

  1. Addresses were geocoded (a location service provider translated an address to a point)
  2. The points have a latitude and longitude value; geometry
  3. A geoprocessing tool identified where these points intersected with polygons (political regions)
  4. The table shows the combined attribute table where a point matched a polygon.

First things:

  • Status of 'U' means that the address was unmatched; no latitude calculated
  • The 'COMM_POLYGONSIZE and COMM_POLUYGONLENTH fields are likely attribute data showing the actual area/size of the polygon. They aren't used in step 3. It's not coordinate-based geometry.

How does it do it? Geoprocessing. Coordinate Systems, geometry-based calculations. Possibly projections and datum transformations. It's not likely to be clean math that can be shown in a table. e.g. here's a couple of tools:

https://pro.arcgis.com/en/pro-app/3.1/tool-reference/analysis/spatial-join.htm

https://pro.arcgis.com/en/pro-app/3.1/tool-reference/analysis/intersect.htm

 

 

0 Kudos