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

[Moritz Lennert]

[Please keep conversations on the list]

On 14/10/15 23:19, Uttam Kumar wrote:
> _
>
> _
> _*This information is for the original data (Source):*_
>
> *PROJ.4 : '+proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181
> +b=6371007.181 +units=m +no_defs '*
>
>
> Coordinate System is:
> PROJCS["Sinusoidal",
>      GEOGCS["GCS_Unknown",
>          DATUM["Unknown",
>              SPHEROID["S_Unknown",6371007.181,0.0]],
>          PRIMEM["Greenwich",0.0],
>          UNIT["Degree",0.0174532925199433]],
>      PROJECTION["Sinusoidal"],
>      PARAMETER["False_Easting",0.0],
>      PARAMETER["False_Northing",0.0],
>      PARAMETER["longitude_of_center",0.0],
>      UNIT["Meter",1]]
> Origin = (-10801805.197699999436736,4130102.079069999977946)
> Pixel Size = (30.000000000000000,-30.000000000000000)
>
> *
> _This information is for the destination data (Target):_*
>
> *PROJ.4 : '+proj=laea +lat_0=30 +lon_0=-96 +x_0=0 +y_0=0 +datum=NAD83
> +units=m +no_defs '*

In your first mail you said:

Lambert Azimuthal Equal Area, Datum: WGS84

but here the datum is NAD83.

Using your projection info, I get almost exactly the same results in 
GRASS as you report from ENVI:

On 08/10/15 21:36, Uttam Kumar wrote:> 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)


GRASS 7.0.1 (test_LAEA):~ > v.info -g Image_Boundary_box
north=1064601.38274499
south=830176.771464028
east=-1960125.15283348
west=-2265106.68066176


Don't have the time now to explore the exact differences, but either 
it's a question of definition of the bounding box, or it possibly be a 
question of which specific NAD83 transformation parameters were used.

Moritz