[GRASS-user] Reprojection of raster maps in various platforms: projected coordinates are different

[Uttam Kumar]

Hi All,

This is the projection information of a single Landsat scene in ENVI, GRASS
and using gdalwarp. GRASS and gdalwarp gave somewhat similar output but
ENVI is totally different. I have been informed that the projected image
from ENVI is correct as verified from the earlier work.

Original data (in Sinusoidal Projection)
------------------------------------------------------
Corner Coordinates:
Upper Left  (-10801805.198W, 4130102.079N)
Lower Left  (-10801805.198W, 3971252.079N)
Upper Right (-10642955.198W, 4130102.079N)
Lower Right (-10642955.198W, 3971252.079N)


Reprojected in GRASS GIS (Lambert Azimuthal Equal Area, Datum: WGS84)
----------------------------------------------------------------------------------
N:    5564460
S:    5185590                        |
E:   -5451390
W:  -5762490

Reprojected in ENVI (Lambert Azimuthal Equal Area, Datum: WGS84)
-------------------------------------------------------------------------
Corner Coordinates:

Upper Left  (-2265106.681W, 1064601.383N)
Lower Left  (-2265106.681W,  830181.383N)
Upper Right (-1960126.681W, 1064601.383N)
Lower Right (-1960126.681W,  830181.383N)

Reprojected using gdalwarp (Lambert Azimuthal Equal Area, Datum: WGS84)
----------------------------------------------------------------------------------
Corner Coordinates:
Upper Left  (-5148766.236W, 3000477.570N)
Lower Left  (-5148766.236W, 2724274.973N)
Upper Right (-4826973.503W, 3000477.570N)
Lower Right (-4826973.503W, 2724274.973N)

Any comment is appreciated.

Uttam.


On Sun, Sep 27, 2015 at 1:48 AM, Markus Neteler <neteler at osgeo.org> wrote:

>
> On Sep 26, 2015 1:00 AM, "Uttam Kumar" <uttamsinha09 at gmail.com> wrote:
> >
> > Thank you all. It worked.
> >
> > However I noticed that the projected boundary values of N, S, W and E in
> GRASS are not same as the values obtained from projecting the same image in
> ENVI image processing software and in gdalwarp.
> >
> > Projection of the scene in Lambert Azimuthal Equal Area is similar (but
> not exactly equal) in GRASS and gdal, but in ENVI it is totally different.
> I just did the comparison to see if things are similar from different
> softwares in case they have to be ported to other platforms.
>
> Can you print the projection information in both GRASS (g.proj -p or -w)
> and ENVI? Are they really the same?
>
> Markus
>
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