topic Converting east/north to Lat/Long using projected Spatial Reference in ArcObjects SDK Questions

Converting east/north to Lat/Long using projected Spatial Reference

EhabNada — Mon, 04 Nov 2019 09:46:55 GMT

Hi,

I'm new in programming using arcobjects, trying to build a desktop arcmap 10.5 add-in using C#, one of the main issues i'm not able to solve is converting (easting/northing) to (latitude/longitude) using same "projected" SpatialReference, that means that the conversion should use the ellipsoid information stored in the same projected spatial reference assigned to the feature.

Thanks,

Re: Converting east/north to Lat/Long using projected Spatial Reference

MelitaKennedy — Tue, 12 Nov 2019 00:50:10 GMT

If you have the spatial reference, get the ProjectedCoordinateSystem, then the GeographicCoordinateSystem from that. Use the GCS as the target/output coordinate system.

Re: Converting east/north to Lat/Long using projected Spatial Reference

EhabNada — Thu, 14 Nov 2019 12:05:07 GMT

Thanks! I'm not experienced in arcobjetcs library, so not sure how to do this but will give it a try, if you have a hint it will be appreciated though.

thanks again.

Re: Converting east/north to Lat/Long using projected Spatial Reference

EhabNada — Wed, 20 Nov 2019 14:12:20 GMT

Hi,

in case someone does need this, with a bit of help from Google, not sure if this is the best way to do it but i was able to do coordinate conversion both ways using one assigned projected geodesy, i'll summarize it:

Try

{

ISpatialReference s1; //this will be used for the feature dataset projected geodesy reference.

ISpatialReference s2; // the Geographic geodesy reference.

IProjectedCoordinateSystem PrjSyst = (IProjectedCoordinateSystem)s1;
string GeographicalCSName = PrjSyst.GeographicCoordinateSystem.Name;

var srProjCSArray = Enum.GetValues(typeof(esriSRGeoCSType));
var srEnvirnonment = new SpatialReferenceEnvironment();

   foreach (var item in srProjCSArray)
   {
      ISpatialReference sr = srEnvirnonment.CreateGeographicCoordinateSystem((int)item);
      if (sr.Name == GeographicalCSName)
      {
         s2= sr;

         //break;
      }
   }

IPoint point;

IGeometry geometry;
geometry = point;

   // from projected to geographic
   geometry.SpatialReference = s1;
   geometry.Project(s2);
   point= (IPoint)geometry;

...........

}

.....