[mapserver-users] Why CRS bounding boxes do not suit?

[Rahkonen Jukka (Tike)]

Hi,

Sorry, this happens probably because I was playing with a new toy and I had edited the EPSG:2393 definitions to use a grid shift file.  I have not made the grid shift table myself but I am almost sure that it does not cover the whole BBOX area. That may be also the reason for the tons of projection library errors I had yesterday.
[Thu Jan 23 11:51:27 2014].685555 msProjectPoint(): Projection library error. proj says: latitude or longitude exceeded limits

This may be judged as a plain user error. However, I wonder if Mapserver could quietly apply zero shift in areas which are not covered be the grid shift file. It may also be a bad idea because Mapserver admin could think that the sparse grid shift file is OK and has some effect on transformations also beyond its extents. What do you think?

-Jukka Rahkonen-




Rahkonen Jukka (Tike) wrote:
> 
> Hi,
> 
> I wonder what goes wrong with calculating the extra bounding boxes into WMS
> GetCapabilities. For example here I have set the wms_extent in the layer
> metadata as "wms_extent" "19970 6597278 749676 7785300" in EPSG:3067
> units.
> 
> Let's check the corresponding values in EPSG:2393 cs2cs +init=epsg:3067 +to
> +init=epsg:2393
> 19970  6597278
> 3019946.27      6600051.87 -28.59
> 749676 7785300
> 3749949.38      7788549.07 -22.66
> 
> Compare with the WMS 1.3.0 GetCapabilities.  Only thing that seems to be
> correct in the <BoundingBox CRS lines is the minx miny in EPSG:3067 that equals
> to what I gave in the metadata.  But the EPSG:3067 maxx maxy is not what I
> gave and EPSG:2393 bbox is all wrong. For example the max  northing is
> announced to be 9852820 while it should be 7788549. Difference is more than
> 2000 km which is too much for a rounding error.
> 
> By the way, when looking at the numbers it is good to know that EPSG:2393 is
> x=northing, y=easting system.
> 
> <EX_GeographicBoundingBox>
> <westBoundLongitude>15.7669</westBoundLongitude>
> <eastBoundLongitude>33.1499</eastBoundLongitude>
> <southBoundLatitude>59.528</southBoundLatitude>
> <northBoundLatitude>70.0976</northBoundLatitude>
> </EX_GeographicBoundingBox>
> <BoundingBox CRS="EPSG:2393" minx="6.62653e+06" miny="3.0678e+06"
> maxx="9.85282e+06" maxy="3.73477e+06"/> <BoundingBox CRS="EPSG:3067"
> minx="68000" miny="6.62375e+06" maxx="734502" maxy="7.77675e+06"/>
> <BoundingBox CRS="EPSG:4326" minx="59.528" miny="15.7669"
> maxx="70.0976" maxy="33.1499"/> <BoundingBox CRS="EPSG:3857"
> minx="1.75517e+06" miny="8.29539e+06" maxx="3.69023e+06"
> maxy="1.11005e+07"/>
> 
> -Jukka Rahkonen-
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