Convert Coordinates from any format to WGS84

[AnkurWalia]

Hi, How can we convert the coordinates from any format to WGS84. I am using C# with Arc objects.

[thejuskambi]

The IGeometry has a method project which you can use to project the geometry object to what ever coordinate system you want.

ArcObjects 10 .NET SDK Help

[YuanLiu]

Could you be more specific about what you are trying to accomplish? For example, if you are just changing spatial reference of the map on-the-fly, IMap, ILayer, and IMapControl all have the SpatialReference property.

[AnkurWalia]

if i have some shape files with any coordinate system (i don't know the coordinates system) and i have use the coordinates of this shape file in my another application which accepts only WGS84 coordinates. I have to read the coordinates from shape file and convert those into WGS84 and provide these to another application. Please provide any solution of this.

Thanks in advance.

[thejuskambi]

Without knowing the source coordinate system it is not possible to convert it to WGS84. you need two coordinate systems to convert between them.

[YuanLiu]

If it comes to geotransformation on spatial reference that's not known yet, this might be interesting: projection conversions - How to use ArcObjects to choose GeoTransformation? - Geographic Information...

One useful trick is to get Geographic Coordinate System differently from geographic and projected coordinate systems

[thejuskambi]

Even that code sample, there is fromSR and ToSR. Any conversion would require type from and to.

If a value X has to be converted to Meters. But you dont know if th value is Feet or inches or miles ... how will you convert?

[MelitaKennedy]

I think the OP means that the input coordinate system could be anything, not that it's completely unknown.

[AnkurWalia]

yes input coordinate system could be anything, we will get the existing coordinate system, after that how to convert that coordinates to WGS84. Please send me some links.

[SachinKanaujia]

If your input is a Geometry (say points) then you can use the below sample

//Create Spatial Reference Factory

            ISpatialReferenceFactory srFactory = new SpatialReferenceEnvironmentClass();

            ISpatialReference sr1;

            //GCS to project from

            IGeographicCoordinateSystem gcs = srFactory.CreateGeographicCoordinateSystem((int)esriSRGeoCSType.esriSRGeoCS_WGS1984);

            sr1 = gcs;

            IProjectedCoordinateSystem pcs = srFactory.CreateProjectedCoordinateSystem((int)esriSRProjCSType.esriSRProjCS_NAD1983N_AmericaLambert);

            pcs.SetFalseOriginAndUnits(0, 0, 1000);

            ISpatialReference sr2;

            sr2 = pcs;

            //Point to project

            IPoint point = new PointClass() as IPoint;

            point.PutCoords(xCoord,yCoord);

            //Geometry Interface to do actual project

            IGeometry geometry;

            geometry = point;

            geometry.SpatialReference = sr2;

            geometry.Project(sr1);

You can use ProjectEx method if you also want to use specific Datum shift methods