[OpenLayers-Users] reprojection issue

[Michael O'Cleirigh]

Hello,

I had a similar type of problem with WMS  in OpenLayers when showing a 
layer served through Geoserver.  i.e. The features were offset 
incorrectly when reprojected onto a Google Maps base layer.

My source layer is in the NAD 83 UTM Zone 17N EPSG:26917 projection. But 
in order to get it to reproject to the Google EPSG:900913 properly I 
needed to first convert the layer into standard NAD 83 degree unit 
projection (4269).

I see that EPSG:32632 is similar to 26917 in that its unit is meter.  
Can you try converting the layer into the appropriate WGS84 degree 
projection first and see if that helps?

Regards,

Mike

> Hi Jan,
>
> Unless I am very much mistaken, http://www.dmap.co.uk/utmworld.htm 
> shows Tunisia to be squarely in UTM 32 N. I have ArcGIS and my 
> landsatt data for the region all fall into UTM 32 N, which is why I 
> believe this is in fact the case.
>
>
> UTM Zone 32 N is also EPSG:32632
>
> http://spatialreference.org/ref/epsg/32632/ so I still don't know what 
> going on.
>
> UTM coordinates are arbitrary cartesian points, which basically could 
> end up anywhere which is why the UTM zone is needed for the origin. 
> The only thing I can think is that yes, there is some issue with the 
> projection, but I don't know what.
>
> On Wed, Jun 10, 2009 at 12:38 PM, Jan Martin 
> <janmartin3 at googlemail.com <mailto:janmartin3 at googlemail.com>> wrote:
>
>     Hi Nicholas,
>
>     your assumption regarding your source UTM Zone beeing UTM 32N is
>     wrong.
>
>     Your coordinates are from Tunisia. And Tunisia is UTM 32S, not UTM
>     32N:
>     http://upload.wikimedia.org/wikipedia/commons/8/85/LA2-Africa-UTM-zones.png
>
>     But as you can see here EPSG:32632 is the right result of a
>     conversion from UTM Zone 32S to EPSG:
>     http://spatialreference.org/ref/epsg/?search=32632&srtext=Search
>     <http://spatialreference.org/ref/epsg/?search=32632&srtext=Search>
>
>     Question remains why your coordinates from Tunisia are displayed
>     in Algeria.
>
>     I wonder if it is OK to just use EPSG:32632 as a projection for
>     your data, or if one would have to do math on the coordinates to.
>     After all your coordinates have been recorded in *WGS84, UTM 32S.*
>
>     Jan
>
>     On Wed, Jun 10, 2009 at 6:08 PM, Nicholas Efremov-Kendall
>     <n.e.kendall at gmail.com <mailto:n.e.kendall at gmail.com>> wrote:
>
>
>         Hello all,
>
>         I believe this is more of a gis question, than for OpenLayers,
>         but the problem manifests itself in openlayers and I'm having
>         some trouble diagnosing it. Jan provided me with some very
>         helpful assistance, which led me to the conclusion that my
>         projection was wrong. I'm trying to display gps point
>         originally recorded in UTM 32N. I had mistakenly believed this
>         was EPSG 22332, but 36232 is actually what I was going for. My
>         problem is this: I have the points overlaid on a wms server
>         (thanks to Jan) but they're in the wrong spot. However, when I
>         change the EPSG code, the points don't move. Does anyone have
>         a suggestion for why they don't move? and or for how to crack
>         this nut.
>         best,
>         Nick
>
>
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