[PATCH] OnEarth Tiled WMS fixes and enhancements

[Lucian Plesea]

The attached patch accomplishes:

• Tiled WMS, eliminated crashes when bbox is the last argument
• Tiled WMS, explicit server variable declaration, to avoid choosing patterns with variables when no values are supplied
• Tiled WMS, support for palette data
• Added NoData, Min and Max support to all WMS formats (server side for tiled WMS)
• Removed some unnecessary fields.

[Lucian Plesea]

WMS driver patch

[Even Rouault]

Woo, this is huge... For better review, it would be highly desirable to break independant fixes into separate patches... I'm going to try to analyze that, but it's going to require some time.

Lucian, do you have sample XMLs for public servers that trigger the new features, so as to verify that we don't break things when applying the fix and potentially doing some adjustments ?

[Lucian Plesea]

It's not really that big of a change. It should not affect other minidrivers, the exception being of a tiny change in the virtual earth one (the default number of levels).

I did change the "daily" xml to point to the current daily modis server.

​http://map1.vis.earthdata.nasa.gov/data/wms.cgi?request=GetTileService

This server had to declare variables, I had it crash with the 1.9.0 code. I had to move the request pattern with no "time" first in the server list to avoid the crash, this code is just smarter on picking up the right pattern to use. And it applies the variable substitution at initialization time since they are static, no need to do it for each and every tile request.

I have also swapped the "Clementine" example for a "Moon" one, which goes to a better mosaic of the moon
​http://onmoon.lmmp.nasa.gov/wms.cgi?request=GetTileService
Or check the polar projection at:
​http://onmoon.lmmp.nasa.gov/NPole/wms.cgi?request=GetTileService
​http://onmoon.lmmp.nasa.gov/SPole/wms.cgi?request=GetTileService

The min/max/nodata should work with any recent server, for example the "simple wcs" with TiledWMS support
​http://onmoon.lmmp.nasa.gov/wcs/wcs.cgi?request=GetTileService

This one does TIFF tiles, some of them in floating point and other with short int, both works fine. It's supposed to be WCS, but the simpleWCS is pretty much identical to WMS, so tiledWMS works just as well. It is needed when accessing elevation for example, to allow proper scaling and masking. The min/max/nodata seemed to be useful by any other driver, so once I had the dataset support built, I let the main driver handle it from the XML.

For palette support, I've just started to update the few servers that have those kind of tiles, you can check against
​http://onmoon.lmmp.nasa.gov/sites/wms.cgi?request=GetTileService
The Color Confidence layers are palette based. Note that you have to extract the bbox declared by the Capabilities for the layer, otherwise the bounding box is always the whole world. We should get the WMS use tiledWMS internally when available to hide this issue, but that is a different patch ;) The palette syntax is borrowed from VRT, allowing interpolation, to keep the server response small.

[Even Rouault]

ok, I think I have merged the gist of your patch in the following commits. Note that I didn't merge the VirtualEarth change as I think it is not appropriate because it exposes a 256x256 overview, whereas the base level of the VirtualEarth data is 512x512.

r24232 /trunk/gdal/frmts/wms/ (dataset.cpp rasterband.cpp wmsdriver.h): WMS: add support for retrieving nodata, min and max values, defined per band or per dataset in the config file (extract of patch by Lucian Plesea, #4613)

r24233 /trunk/gdal/frmts/wms/ (dataset.cpp rasterband.cpp wmsdriver.h): WMS: add support for GetColorTable(), that will be later used by the TiledWMS mini driver (extract of patch by Lucian Plesea, #4613)

r24234 /trunk/gdal/frmts/wms/ (4 files): WMS: update TiledWMS mini-driver to support new variable substitution mechanism, min/max/nodata settings, color table support (extract of patch by Lucian Plesea, #4613)

r24235 /trunk/gdal/frmts/wms/ (dataset.cpp wmsdriver.h): WMS: remove m_overview_count member (extract of patch by Lucian Plesea, #4613)

r24236 /trunk/autotest/gdrivers/wms.py: Test a TiledWMS dataset with a color table (#4613)

[warmerdam]

Reopening to review the sample xml changes.

[Even Rouault]

This ticket has been automatically closed because Trac is no longer used for GDAL bug tracking, since the project has migrated to GitHub. If you believe this ticket is still valid, you may file it to ​https://github.com/OSGeo/gdal/issues if it is not already reported there.