topic Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting in Data Management Questions

Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

RegunathanUmapathy — Mon, 04 Aug 2014 07:24:37 GMT

Hi,

I am from Sri Lanka. Northern Sri Lanka is in UTM Zone 44. If the data been collected in UTM Zone 44N and If I (or someone) convert it to Kandawala Sri Lankan Grid (Available in ArcGIS 10.1 as Projected Coordinate Systems -> National Grids -> Asia -> Kandawala Sri Lanka Grid) there seems to be shifting around 200 meters on the east. However if I use DNR GPS software from DNRGPS Application: Minnesota DNR load the shape file then if I set (from the DNR GPS) the file -> Set Projections -> Datum as Kandawala and Projection as Sri Lankan Grid only few meter difference which is acceptable. I have verfied this with 2 Garmin GPS one set to UTM Zone 44n and other set to Sri Lankan Grid . I shall be thankful if I can sort out the issue in ArcGIS.

Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

DanPatterson_Retired — Mon, 04 Aug 2014 09:23:22 GMT

This type of shift is normally associated with a datum shift. Are you sure that the datums are the same?

Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

NeilAyres — Mon, 04 Aug 2014 09:45:47 GMT

Did you set a transformation (datum shift) under the cords tab in the data frame properties page?

You have a single geocentric transform available (ArcGIS v10.2) for WGS84 to/from Kandawala, dx, dy, dz parameters -97.0, 787.0, 86.0.

That will be the likely cause of your 200m shift.

Neil

Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

RegunathanUmapathy — Tue, 05 Aug 2014 03:28:07 GMT

Dear Dan Patterson,

No. The datum UTM Zone 44n is WGS84 while for Kandawala Sri Lankan Grid Datum is Kandawala. Geotrans software NGA: (U) MSP GEOTRANS 3.4 Geographic Translator (UNCLASSIFIED) also provide resonably accurate transformation.

Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

RegunathanUmapathy — Tue, 05 Aug 2014 04:22:48 GMT

Dear Neil Ayres,

Many thanks for the reply. You may have a look at the original gpx via https://onedrive.live.com/embed?cid=45B0A8A523ED0470&resid=45B0A8A523ED0470%21585&authkey=ADgKMvA2w_SXcvU file from the garmin etrex10 GPS (with GLONASS enabled) that can easily open dnr gps and save as a a arcgis shaefile from there.

I set the data frame properties to Kandawala Sri Lankan Grid

I have added the layer which was set at UTM Zone 44n with WGS 84datum.
When I added it gave Grographic Coordinate System Warning which is given below

I have clicked the Transformation

If I simply click Convert from GCS_WGS_1984 to GCS_Kandawla and click ok results around 200m shifting in the east as I mentioned via a screenshot above. However if I choose using (choices are sorted by suitability for the layer's extent) using geocentric transoformation geocentric transformation it works and the answer is quite close.

Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

NeilAyres — Tue, 05 Aug 2014 07:51:03 GMT

Rangunathan,

exactly,

you have to chose the correct transformation.

If this is has answered your problem, please mark the post as such.

Re: Projection Issues (Converting from UTM Zone 44N to Kandawala SriLanka Grid) shifting around 200 meters in the easting

DonOpgenorth — Tue, 05 Aug 2014 15:02:40 GMT

I've moved your post into the GIS Mapping Data space. GeoNet Help is intended for discussion on the community help and feedback. I have also added in a few additional tags. You can see more on the community structure, and what topics are under each space from the
following documents:

GeoNet Community Structure

ArcGIS Discussion Forums Migration Strategy

Thanks!

Don