topic Everest 1830 to WGS 1984 in Coordinate Reference Systems Questions

Everest 1830 to WGS 1984

PradeepJoshi — Tue, 01 Sep 2015 11:44:12 GMT

Hello,

Please tell me how do I project a shapefile from Everest 1830 to WGS 1984? I can not find any transformation method for this.

Thank you.

Re: Everest 1830 to WGS 1984

JayantaPoddar — Tue, 01 Sep 2015 12:33:29 GMT

Hi Pradeep,

I am quoting a comment of Melita Kennedy from Coordinate transformation from WGS 1984 to Everest 1830 or vice versa?

We don't have any transformations for Everest 1830 because it's a ellipsoid (spheroid) and not a true geodetic datum/coordinate system. The data may be using Kalianpur 1937. Take a look at the geographic_transformations.pdf file located in your ArcGIS installation's Documentation folder for GCS that are used in India (or wherever the data is) and try some of them. It will mean redefining the Everest 1830 data with the Define Projection tool or the data's property page in ArcCatalog.
Melita

What happens if you reproject the data from Everest 1830 to WGS 1984 without using any transformation?

Project—Help | ArcGIS for Desktop

Re: Everest 1830 to WGS 1984

PradeepJoshi — Tue, 01 Sep 2015 12:50:43 GMT

Thanks. But Melita's comment does not help me. The Kalianpur 1937 shows coordinates in negative meters and displays errors on invalid map extents while projecting to WGS 84.

What happens if you reproject the data from Everest 1830 to WGS 1984 without using any transformation?
Project—Help | ArcGIS for Desktop

If I do so it displays an error message saying Undefined geographic transformation.

Re: Everest 1830 to WGS 1984

JayantaPoddar — Tue, 01 Sep 2015 13:07:08 GMT

I could reproject a shapefile in Everest 1830 to GCS_WGS_1984 without any error. What is your exact source and target coordinate system?

Re: Everest 1830 to WGS 1984

PradeepJoshi — Tue, 01 Sep 2015 13:13:16 GMT

I am trying to project a shapefile to GCS WGS 1984 that has following projection information.

PROJCS["M_UTM",GEOGCS["GCS_Everest_1830",DATUM["D_Everest_1830",SPHEROID["Everest_1830",6377299.36,300.8017]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",84.0],PARAMETER["Scale_Factor",0.9999],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]

I think this is based on the Everest 1830 if not exact the same.

Re: Everest 1830 to WGS 1984

MelitaKennedy — Tue, 01 Sep 2015 18:05:01 GMT

Hi Pradeep,

Because you said you were getting negative values after projecting the data, can you post the extents of the dataset?

We don't have a lot of information about transformations in India. There's one, Indian_1975_To_WGS_1984_1, that covers India and Nepal, but it's questionable. Survey of India just doesn't release that much information.

I would suggest modifying the data's coordinate system by replacing the geographic coordinate system with Indian 1975. You can do this through the data's property page in ArcCatalog. Next use the Project tool to create a new dataset in WGS84.

Melita

Re: Everest 1830 to WGS 1984

PradeepJoshi — Wed, 02 Sep 2015 06:21:54 GMT

Dear Melita,

I have attached the shapefile here. Would you please have a look?

Re: Everest 1830 to WGS 1984

JayantaPoddar — Wed, 02 Sep 2015 08:31:06 GMT

Pradeep,

I could successfully reproject the attached data to WGS_1984_Web_Mercator_Auxiliary_Sphere (No transformation method used). Let us know if you face any issue.

Re: Everest 1830 to WGS 1984

PradeepJoshi — Wed, 02 Sep 2015 10:29:16 GMT

Thanks. It worked for me too. But I was trying to project to Geographic coordinate systems ==> World (not spheroid based) ===> WGS 1984.

I am not sure whether projecting to WGS_1984_Web_Mercator_Auxiliary_Sphere produces any error.

Re: Everest 1830 to WGS 1984

JayantaPoddar — Wed, 02 Sep 2015 11:18:29 GMT

Even reprojection to GCS_WGS_1984 is done successfully. And I don't see any mismatch between the two data.