If all you want to do with SqlGeography is track points and take advantage of SQL Server 2008’s spatial indices, you can, as others have noted, hide your spatial data column from Linq to SQL and use UDFs or stored procedures. Suppose that you have a table AddressFields that includes Latitude and Longitude fields. Add … Read more
The Haversine formula assumes a spherical earth. However, the shape of the earh is more complex. An oblate spheroid model will give better results. If such accuracy is needed, you should better use Vincenty inverse formula. See http://en.wikipedia.org/wiki/Vincenty’s_formulae for details. Using it, you can get a 0.5mm accuracy for the spheroid model. There is no … Read more
I’ve got XML for US state polygons here. I use them like this. I deliberately kept the detail fairly light to reduce the loading time and end up with a map that’s reasonably responsive in slow browsers. I don’t have anything for Canada.
No Library, No Nothing. Copy This! Using These Two Classes , You can Convert Degree(latitude/longitude) to UTM and Vice Versa! private class Deg2UTM { double Easting; double Northing; int Zone; char Letter; private Deg2UTM(double Lat,double Lon) { Zone= (int) Math.floor(Lon/6+31); if (Lat<-72) Letter=”C”; else if (Lat<-64) Letter=”D”; else if (Lat<-56) Letter=”E”; else if (Lat<-48) Letter=”F”; … Read more
There several ways to do this. 1) Integrate the contributions from latitudinal strips. Here the area of each strip will be (Rcos(A)(B1-B0))(RdA), where A is the latitude, B1 and B0 are the starting and ending longitudes, and all angles are in radians. 2) Break the surface into spherical triangles, and calculate the area using Girard’s … Read more
Update: 04/2018: Vincenty distance is deprecated since GeoPy version 1.13 – you should use geopy.distance.distance() instead! The answers above are based on the Haversine formula, which assumes the earth is a sphere, which results in errors of up to about 0.5% (according to help(geopy.distance)). Vincenty distance uses more accurate ellipsoidal models such as WGS-84, and … Read more
Calculate distance between 2 GPS coordinates