topic Re: Conversion of Feet Coordinates to Decimal Degrees in Developers Questions

Conversion of Feet Coordinates to Decimal Degrees

ZacheryBettis — Tue, 17 Mar 2015 18:04:18 GMT

I'm trying to programmatically convert (in C#) feet coordinates to decimal degrees. I'm not so worried about the actual programming (although it would be nice if someone has already created code for this) as I am the math behind the conversion. I've included my coordinate system details below in case they're needed. How can I accomplish this?

Example:

1,985,012.726 449,396.204 Feet --> -97.548833 32.901945 Decimal Degrees

Coordinate System:

NAD_1927_StatePlane_Texas_North_Central_FIPS_4202

WKID: 32038 Authority: EPSG

Projection: Lambert_Conformal_Conic

False_Easting: 2000000.0

False_Northing: 0.0

Central_Meridian: -97.5

Standard_Parallel_1: 32.13333333333333

Standard_Parallel_2: 33.96666666666667

Latitude_Of_Origin: 31.66666666666667

Linear Unit: Foot_US (0.3048006096012192)

Geographic Coordinate System: GCS_North_American_1927

Angular Unit: Degree (0.0174532925199433)

Prime Meridian: Greenwich (0.0)

Datum: D_North_American_1927

Spheroid: Clarke_1866

Semimajor Axis: 6378206.4

Semiminor Axis: 6356583.799998981

Inverse Flattening: 294.9786982

Re: Conversion of Feet Coordinates to Decimal Degrees

MelitaKennedy — Tue, 17 Mar 2015 18:45:36 GMT

Are you converting a feature class to another feature class or working with individual geometries? For the latter, look at IGeometry2::ProjectEx. What is the output GCS going to be? NAD27, NAD83, etc.? For anything other than NAD27, you'll also need a geographic (datum) transformation like 1241 (NAD_1927_To_NAD_1983_NADCON) or 15851 (NAD_1927_To_WGS_1984_79_CONUS).

Another possibility is to use the Project Tool via Python.

Melita

Re: Conversion of Feet Coordinates to Decimal Degrees

ZacheryBettis — Tue, 17 Mar 2015 19:01:16 GMT

This is part of a tool that identifies a mouse click location in ArcMap and locates it on online maps. The output coordinates will be used to find locations on Bing and Google Maps.