[mapguide-internals] RE: Motion: RFC 30 - FDO Configuration

Jason Birch Jason.Birch at nanaimo.ca
Thu Sep 6 00:15:16 EDT 2007

Hmm.  Now I'm feeling a bit stupid; as long as the <Bounds> element shows up in the config file, it's all good.
Oh wait.  I don't think that I can reverse-engineer insertionpoint / resolution / rotation from an image's SpatialContext.  Right now, what I'm doing is creating a temporary connection to each image in a directory, running a GetExtent against its SpatialContext, and grabbing the ll/ur coordinates from the extent's Envelope.  
I think I'd be stuck either with template-based config file generation, or with using an external utility like gdalinfo.  I'd prefer the former I think; I've tried to avoid dependencies.  
If I'm not wrong about the lack of APIs for extracting a single image's insertion/rotation/resolution (maybe I should just say worldfile), is there any chance of adding a way of specifying the Bounds and not populating the insertion/resolution/rotation values?
Or does what you're saying about the lack of a physical mapping for Bounds preclude this entirely?


From: mapguide-internals-bounces at lists.osgeo.org on behalf of Leaf Li
Sent: Wed 2007-09-05 8:54 PM
To: mapguide-internals at lists.osgeo.org
Subject: [mapguide-internals] RE: Motion: RFC 30 - FDO Configuration

Hi Jason,

Bound override for Raster provider is done by insertpoint, resolution,
rotation override. If you take a look at schema override of Raster
provider, you will find there is no bounds override in its physical
schema mapping. Actually bound can be computed from insertpoint,
resolution, rotation override. So you can implement bound override from
insertpoint, resolution, rotation override.

As for specifying the layer to be used for each MgRasterWMSItem, it is
done by from MgRasterItem::m_name. For MgRasterFileItem, it means raster
file name. For MgRasterWmsItem, it means layer name.

I agree with you. One sample make more sense. I will add it later.


Leaf Li

From: "Jason Birch" <Jason.Birch at nanaimo.ca>

Subject: RE: [mapguide-internals] Motion: RFC 30 - FDO Configuration

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Hi Leaf Li,

Maybe I'm missing something, but I don't see support for the Bounds
override in MgRasterFileItem.

I don't see where you would specify the layer to be used for each
MgRasterWMSItem ... is the name of the MgRasterItem used for that?  One
of the largest benefit of config files with the WMS provider is being
able to ask the server for multiple layers in a single request.  An
example would help my understanding.



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