topic Re: Set ArcMap Data Frame in Decimal Degrees Using ArcObjects in ArcObjects SDK Questions

Set ArcMap Data Frame in Decimal Degrees Using ArcObjects

ShaningYu — Fri, 30 Jun 2017 17:26:20 GMT

I use a piece of code for dynamically loading feature layers. Either before or after the loading, I need to set the Data Frame in Decimal Degrees. Is there such a piece of code that can set / change the Data Frame's setting? Thanks.

Re: Set ArcMap Data Frame in Decimal Degrees Using ArcObjects

KenBuja — Fri, 30 Jun 2017 18:45:32 GMT

Use the IMap.DistanceUnits property

Re: Set ArcMap Data Frame in Decimal Degrees Using ArcObjects

ShaningYu — Fri, 30 Jun 2017 19:20:46 GMT

Ken:

Thanks for your hint. Below is the code I have. But I can't QI to Decimal Degree. What's wrong in my code? Thanks.

                        m_mxDoc = (IMxDocument)app.Document; //m_app.Document;
                        m_Map = m_mxDoc.FocusMap;
                        m_activeView = (IActiveView)m_Map;

                        ISpatialReference spRef = m_Map.SpatialReference;
                        IProjectedCoordinateSystem pProjectedCoordinateSystem = spRef as IProjectedCoordinateSystem;
                        ILinearUnit pLinearUnit = pProjectedCoordinateSystem.CoordinateUnit;

Re: Set ArcMap Data Frame in Decimal Degrees Using ArcObjects

KenBuja — Fri, 30 Jun 2017 19:33:43 GMT

I believe you're overthinking it. Try this

m_Map = m_mxDoc.FocusMap;

m_Map.DistanceUnits = esriDecimalDegrees

Re: Set ArcMap Data Frame in Decimal Degrees Using ArcObjects

ShaningYu — Mon, 03 Jul 2017 13:32:04 GMT

Ken:

Thanks for your response. I revised my program. But after the feature layers are loaded, the frame still shows feet as the unit. Besides, the returned values (Calculated central X & Y) are still in feet. Any new idea? Thanks.

Re: Set ArcMap Data Frame in Decimal Degrees Using ArcObjects

DuncanHornby — Mon, 03 Jul 2017 15:36:34 GMT

If the underlying data is in feet then a field calculate will return feet even though the map is displaying in decimal degrees. Also there is a difference between MapUnits and DistanceUnits read the remarks section here.