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Last Post 26 Aug 2020 01:11 AM by ANINDITA MOHANTY

Projected raster envi 5.1

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anon

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28 Oct 2014 02:18 AM
Hi, can someone tell me how can i do something like (In Envi 4.7) Map--> Convert map projection in Envi 5.1? I guess that i must use the projected raster tool, but the problem is that i have a custom datum that i want to use. In Envi 4.7 i just add the datum to the datums text file, but in Envi 5.1 it doesn´t work. Actually what i want is to project from UTM WGS84 29 to ED1950 UTM 30, i should use the NTv2 grid to perform the transformation, i have found a folder in the exelis directory where i have that grid but i don't realize how to use it (it is in a gsb file). Thanks

MariM

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Posts:2396
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28 Oct 2014 07:30 AM
You do use the Reproject Raster tool in ENVI 5.x to have full access to all the available projections and datums. I was able to find the ED1950 datum by searching for 'ED' which turns up European Datum 1950 (ED77). Is this what you are looking for?

Deleted User

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28 Oct 2014 10:05 AM
Hi MariM, No, i also find the ED 1950, but i mean that i has a special datum, not very sure about how to explain it, but in Envi 4.6 i only must to add a new line to the datum.txt (ED 1950 PS, International (ellipsoid), -84, -107, -120 (parameters to perform the projection), and that was all about. In Envi 5.x i try to do the same process but it doesn't work. I have found this: http://www.exelisvis.com/...cleID/4455/4455.aspx Surely what i need, i still hvae to read it.

MariM

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Posts:2396
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28 Oct 2014 02:41 PM
ENVI started using the Esri Projection engine in ENVI 4.7 and it supports many more projections and datums that previous versions. Are you sure your datum is not listed? The European Datum 1950 also uses the International spheroid. I think it is the same datum. If it is not supported in the Esri Projection engine, then it is not supported: http://www.exelisvis.com/Support/Help...

Deleted User

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30 Oct 2014 01:42 AM
Yes, but what i want is to reproject using the NTv2 grid, in ArcGIS i do something like project from wgs 84 UTM 29 to ed 1950 UTM 30 and then i choose the ntv2 option to do the reprojection. In Envi 4.6 i only must add a new datum with 3 parameters to perform the projection, slightly different to those of the ED1950. But i don't see how to do the same in Envi 5.x or 4.7/8. I have found a folder called Ntv2, so i guess that somehow i must be able to perform the projection in the same way i do it in ArcGIS but i don't find it out.

MariM

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Posts:2396
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31 Oct 2014 06:33 AM
I believe this help article describes how to change the geographic transform method: http://www.exelisvis.com/Portals/0/He... Here are the transforms that include the NTV2: http://www.exelisvis.com/Portals/0/He...

ANINDITA MOHANTY

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Posts:2

26 Aug 2020 01:11 AM
I need to add " Moon Sphere 1737.4" in datum text file and it's corresponding projection ellipsoid in ENVI. How to do that?

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