[mapserver-users] Projection problems

[Jan Hartmann]

(Sorry for crossposting to the PROJ list, but this has been a problem 
for years going)

Yes, the transformation to WGS84 for the Dutch coordinate system 
("Amersfoort", "Rijksdriehoeksnet) is still *not* part of the latest 
PROJ4 release (4.7.0, downloaded yesterday). You need to change the 
formula for epsg:28992 in PROJ's epsg table and in PosGIS's 
"spatial_ref_sys" table, like Milo describes, else your maps will be 
about 100 meters off. You can read an extensive discussion about this, 
including an Excel spreadsheet to compute the towgs84 parameters from 
the official EPSG database at:

http://trac.osgeo.org/geotiff/ticket/22

PROJ gets its parameters from EPSG, but somehow it still doesn't manage 
to include the WGS84 transform.

Vriendelijke groeten,

Jan



On 01/07/11 15:22, Milo van der Linden wrote:
> Funny,
>
> Everytime I read "projection problems" on this list I think: Hey, this 
> might be someone from the Netherlands.
>
>
> You mean you would really like to have your bedrijventerreinen like this?
>
> http://www.locatiemonitor.nl/LocationDetails2.aspx?lid=1437
>
> (please wait for the bedrijventerreinen wms to appear)
>
> I created the wms service for locatiemonitor and as I can see, we are 
> "fishing in the same vijver"
>
> Please read my blog post at 
> http://blog.dogodigi.net/2010/08/19/dutch-coordinate-system-ellipsoid-correction/
>
> And write a small thank you comment if it helped you solve your issue
>
> ;-)
>
> Kind regards,
>
> Milo van der Linden
>
> 2011/1/7 basvmrs <bas at cipix.nl <mailto:bas at cipix.nl>>
>
>
>     Hi,
>
>     I've created a map server in which I try to output data that was
>     entered
>     using Google Maps V2 (drawing polygons). I used openlayers to
>     display the
>     results over a Bing layer.
>
>     There seems to be a problem in the projection, which is best
>     described using
>     an image and a link:
>
>     http://bir.cipixtest.nl/resources/gis/demo.html Demo
>     http://osgeo-org.1803224.n2.nabble.com/file/n5898717/forum.png
>
>     Notice how the areas seem to 'shift' when zooming in.
>
>     My mapfile looks like this:
>
>
>     #
>     # Start of map file
>     #
>     MAP
>            NAME BIR
>            STATUS ON
>            SIZE 600 600
>            EXTENT 4.4 51.85 4.6 51.95
>            UNITS METERS
>
>            IMAGETYPE PNG
>
>            PROJECTION
>                    "init=epsg:900913"
>            END
>
>            TRANSPARENT ON
>
>            LAYER
>                    NAME bedrijventerreinen
>                    TYPE POLYGON
>                    STATUS DEFAULT
>                    CONNECTIONTYPE OGR
>                    CONNECTION
>     "MySQL:bir,host=XXXXX,user=XXXXX,password=XXXXXXX,port=3306"
>                    DATA "SELECT * from gis_object"
>                    DUMP TRUE
>                    CLASS
>                            NAME 'Bedrijventerreinen'
>                            STYLE
>                                    OUTLINECOLOR 0 0 0
>                                    COLOR 200 200 200
>                            END
>                    END
>                    TEMPLATE "object.html"
>
>                    METADATA
>                            gml_include_items "all"
>                            WMS_TITLE "Bedrijventerreinen"
>                            WMS_ABSTRACT "Bedrijventerreinen in de
>     Regio Rotterdam; de gebieden zijn
>     een benadering en er kunnen geen rechten aan worden ontleend."
>                            WMS_SRS "EPSG:28992 EPSG:900913 EPSG:4326"
>                    END
>            END
>
>     END # Map File
>
>     I don't have a clue why this is happening. I hope that someone can
>     explain
>     to me why this is happening and how to fix it.
>
>     Kind regards,
>     Bas
>     --
>     View this message in context:
>     http://osgeo-org.1803224.n2.nabble.com/Projection-problems-tp5898717p5898717.html
>     Sent from the Mapserver - User mailing list archive at Nabble.com.
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>
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