[Proj] Misplaced SHP obtained with PROJ 4.8.0 called from gvSIG CE
jorge.arevalo at geomati.co
Sun Aug 25 15:16:18 EST 2013
On Wed, Aug 21, 2013 at 8:15 PM, Hermann Peifer <peifer at gmx.eu> wrote:
> On 2013-08-21 17:04, Jorge Arevalo wrote:
>> I'm trying to fix a bug related with PROJ in gvSIG CE. This desktop
>> client creates its own JNI wrapper, based on PROJ sources. The
>> reprojection of shapefiles using grid files works with the wrapper
>> based on PROJ 4.5.0, but it fails if we construct the same wrapper
>> based on any upper version of PROJ (PROJ 4.8.0, for example).
>> Here, the use case that causes the problem:
>> - We want to reproject this shapefile from epsg:23030 to epsg:25830:
>> - We want to use this grid file to perform the operation:
>> The operation done with the JNI wrapper based on PROJ 4.5.0 works
>> fine. But if we use PROJ 4.8.0 as base, we get a misplaced file. Here,
>> a screenshot. In blue, the original shapefile. In green, the shapefile
>> correctly reprojected (PROJ 4.5.0). In red, the misplaced shapefile
>> (PROJ 4.8.0)
>> Debugging, we found the problem is in pj_transform.c. I guess it's
>> related with the way we pass information to PROJ functions. I've made
>> a diff between both versions (pj_transform in PROJ 4.5.0 and PROJ
>> 4.8.0), but I see several changes, and I don't know where to focus.
>> Any clue?
>> Many thanks in advance, and best regards,
> I assume that this is your definition of the target SRS:
> +proj=utm +zone=30 +ellps=GRS80 +units=m +no_defs
> if yes, you'd have to change it to:
> +proj=utm +zone=30 +ellps=GRS80 +nadgrids=@null +units=m +no_defs
> Further reading: Why do I get different results with 4.5.0 and 4.6.0?
Yes, I think that is definitely related with my problem. My SRS
definition string is incorrect. Now, I need to review the way it's
built in gvSIG CE. Many thanks for putting me in the right track!
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