[mapguide-internals] RFC30 is posted

[Jason Birch]

Thank you for the clarification;  I guess I wasn't entirely clear.
 
As it stands, the RFC is a good high-level document providing an overview of the enhancements, and the classes that will be created.  What I would really like to see is a list of the proposed methods along with their signatures.  I can see a few in the example (AddSpatialContext, AddOverrideInfo, ToXML) but would like to see all of them to know which overrides will / will not be possible, etc.
 
I'm not clear on whether the overrides you're supporting for raster include bounds (min_x,min_y, max_x, max_y).  This is critical for performance of the raster provider, so if you don't support this, I'll still have to hack the resultant XML to add bounds definitions.
 
I'd really like to see an example in the RFC of how to create a basic WMS config file with multiple layers.  For instance: http://trac.osgeo.org/fdo/browser/trunk/Providers/WMS/Src/UnitTest/MultiLayers_Config.xml
 
It appears that there is a difference between the object model graphic and the text (MgRfpConfigDocument vs. MgRasterConfigDocument).  I personally favour the second for its readability.
 
Jason

________________________________

From: mapguide-internals-bounces at lists.osgeo.org on behalf of Leaf Li
Sent: Thu 2007-08-30 6:32 PM
To: mapguide-internals at lists.osgeo.org
Subject: RE: [mapguide-internals] RFC30 is posted



Answer in lines



Interesting idea.  I'd really like to see more information on:



- what overrides / parameters will be accessible for each of the various providers.  For instance, I'd like to see whether it will allow the specification of multiple layers and alternate styles from a WMS, the use of a specific image format, etc.  If you look on the FDO mailing list, there was a long thread from someone having difficulty generating WMS config documents.  Here's part of it:  http://www.nabble.com/RE%3A--mapguide-users--Advanced-WMS-provider-configuration-tf3567897s18162.html#a9967178 <http://www.nabble.com/RE%3A--mapguide-users--Advanced-WMS-provider-configuration-tf3567897s18162.html#a9967178>



[Leaf Li] Nearly all information that can be overrided will be accessable by MgConfigDocument. For Raster provider, MgRasterFileItem will provide all override information, which allows the specification of image location, insert point, resolution, rotation, comibination of multiple images. For WMS provider, MgRasterWmsItem will provide all override information which allows the specification of multiple layers, styles, image format, coordinate system, transparent, background color.



- whether this will work with the open source GDAL raster provider

[Leaf Li] Yes. It will work with the open source GDAL raster provider.



- whether this relies on GetSchemaMapping returning accurate results

[Leaf Li] It nearly doesn't relies on GetSchemaMapping. However,  if users want create a configuration based on an existing connection, we need call GetSchemaMapping in this time.



- how this ensures that valid config documents will be generated (validate against schema?)



[Leaf Li] When users add override information by AddOverrideInfo method, the feature class and its physical mapping will be created in the same time. MgConfigDocument will guarantee feature class and its physical mapping is valid.



Oh and most importantly... I recently wrote a PHP app to create a config document for the GDAL provider (including bounding boxes) by pointing to a directory on the server that contains images. (http://trac.osgeo.org/fdo/wiki/FdoGdalNotes#CreatingTileIndexConfigFiles <http://trac.osgeo.org/fdo/wiki/FdoGdalNotes#CreatingTileIndexConfigFiles> )  Will this RFC make this job easier?  :)



[Leaf Li] Definitely.



----Leaf Li