Simon Greig wrote:
Hi,
This is a follow up to a question a colleague asked a few weeks ago:
http://lists.osgeo.org/pipermail/mapserver-users/2008-March/054772.html
To summarise:
In order to improve performance in our java application that uses the
mapscript API we have replaced:
mapobj.setProjection("init=epsg:27700");
with
private static final String PROJECTION_WK_EPSG_27700 = "PROJCS[\"OSGB 1936
/ British National Grid\",GEOGCS[\"OSGB
1936\",DATUM[\"OSGB_1936\",SPHEROID[\"Airy
1830\",6377563.396,299.3249646,AUTHORITY[\"EPSG\",\"7001\"]],AUTHORITY[\"EPSG\",\"6277\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.01745329251994328,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4277\"]],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"latitude_of_origin\",49],PARAMETER[\"central_meridian\",-2],PARAMETER[\"scale_factor\",0.9996012717],PARAMETER[\"false_easting\",400000],PARAMETER[\"false_northing\",-100000],AUTHORITY[\"EPSG\",\"27700\"]]";
...
mapobj.setWKTProjection(PROJECTION_WK_EPSG_27700);
We have also changed the code to use the WKT projection method for each
layer.
As Rob says the performance improvement is way better and we thought we
had a winner.
Unfortunately we have a problem based on the size of the image and
bounding box.
If we ask for a small bounding box (roughly 1 mile by 1 mile) with a
1000x800 PNG image then it works
If we ask for a large bounding box (roughly 500 miles by 500 miles) with a
200x200 PNG image then it works
If we ask for a large bounding box with a 300x300 PNG image then we get
this error:
"Layer must have an EPSG or AUTO projection code (in its PROJECTION object
or wms_srs metadata)"
Unfortunately Rob is on leave and I am looking after things in his
absence. Any help is much appreciated :-)
Simon,
I'm not sure what is going on here exactly. I *suspect* that your bigger
window is the first time some of this data is getting pulled in but I'm not
sure. Do you still set the corresponding epsg code in the wms_srs metadata?
It may be that you could skip the WKT operations and just re-order the
epsg init file so that 27700 is at the top to get equally good speed up
with lets side effects.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, [EMAIL PROTECTED]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
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