[GRASS-user] Re-projected Data Position Mismatch

Anna Petrášová kratochanna at gmail.com
Sun Aug 27 19:54:42 PDT 2017


On Tue, Aug 22, 2017 at 7:46 PM, Jeshua Lacock <jeshua at 3dtopo.com> wrote:
>
> To hopefully help troubleshoot; I just reprojected one of the raster tiles (from epsg: 3857), into the source location of one of the lonlat vectors (reverse projections from my OP), and the datasets are offset by the same distances. Since the dimensions of the raster are being changed (by r.proj), it leads me to think it must be a datum or coordinate system misalignment and not a projection issue.

I have the same problem, working with NAIP imagery. It is related to:
https://trac.osgeo.org/grass/ticket/2229

I have to remove nadgrids: @null from the PROJ_INFO file to be able to
reproject into that location, but then it is shifted. gdalwarp helps.

>
> For example, here is a test raster tile in the Comp Projection (epsg: 3857): http://3DTOPO.com/epsg_3857.png
>
> And in the reverse lonlat projection: http://3DTOPO.com/lonlat.png
>
> (the raster tile should be located in the red area in both examples)
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