[Qgis-developer] QgsMapCanvas with Dimap data

Radim Blazek radim.blazek at gmail.com
Wed Jan 26 09:36:09 EST 2011


At this moment there is no support to do this neither in raster
providers branch.
All the providers (GDAL,GRASS, WMS) are using a library/service
functions to get
required extent / resolution. I have to check however, if GDAL warp
(used for that in GDAL provider)
is fast enough. If not, we have to return to QgsRasterViewPort, and
that would become
available for all providers.

Radim

On Wed, Jan 26, 2011 at 5:38 AM, Tim Sutton <lists at linfiniti.com> wrote:
> Hi John
>
> On Mon, Jan 24, 2011 at 6:01 PM, John de Muller
> <john.de.muller at gmail.com> wrote:
>> Good day
>>
>> I currently have some QgsRasterLayers without any metadata stored in the
>> image file itself. All the metadata (eg: coordinates, rows, columns, crs,
>> etc) is stored in an external Dimap (.dim) file. How can a pass these
>> coordinates (like the top-left corner of the layer) to QgsRasterLayer or
>> QgsMapCanvas so that the work with the real coordinates and not the pixel
>> values.
>>
>> For instance: When I currently load the image, the coordinates QGIS uses is
>> the width and height (in pixels) of the image (eg: 800*600). I want to
>> adjust these values so that they represent real world coordinates (with the
>> metadata from the dim file).
>>
>> I've found the the QgsRasterViewPort, but it seems like it is not possible
>> to set these values through QgsRasterLayer. Any kind of help would be
>> appreciated.
>>
>
> I guess most people would use gdalwarp or similar to assign this info
> directly to the image. On the premise that you don't wish to do that,
> I suspect that the upcoming merge of the raster projection branch may
> be useful to you since it includes support to create new raster
> provider types. In the provider definition you should be able to deal
> with parsing the dimap file and registering the image internally. Note
> I havent tested this so perhaps Radim can comment more usefully.
>
> Regards
>
> Tim
>
>
>> Thank you.
>> John
>>
>>
>>
>>
>>
>> _______________________________________________
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>> Qgis-developer at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>
>>
>
>
>
> --
> Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
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