0

I am enroute to create an app that finds nearest venues. I already have another SO question on this regard.

I don't have any experience with such features, and some of the concepts are not being very obvious to me. So, I have been thinking that I am not taking things on right direction.

I have seen in number of places with both GIS and in case of mobile towers, the range is calculated in polygons. I have also been reading a bit about Haversine Formula, and it appears it does not use Polygon, it is basically two-point distance (from my understanding).

  1. Why use Polygon for reference ?
  2. Why is circle not used for this ?
  3. How does Haversine formula integrate with this polygons concept ?
Community
  • 1
  • 1
Kishor Kundan
  • 3,135
  • 1
  • 23
  • 30

1 Answers1

1

I believe polygons are used because of the different coordinate reference systems. Drawing a circle on certain reference systems would not actually appear be a circle, but some sort of oval depending on the CRS. (Since a map is a 2d representation and the earth is an ellipsoid)

They are stored as polygons because you would have to do the calculations to draw that circle again in the specified CRS. If you store it as a polygon of points, you just have to plot them, and the database stores them in the CRS you define.

You might want to try this at gis.stackexchange.com, They will have a better answer for you

Nate
  • 1,889
  • 1
  • 20
  • 40