GDAL Provider Accesses data even if layer not visible

[amorsell@…]

version 1.2.0 beta 2

This seems to happen only the first time a map is accessed after a given MapGuide Server service start. If the map has a GDAL based layer, even if the layer is not visible on the map both from the settings in the map and from it's zoom scale threshold, the GDAL provider still attempts to read every image within that data connection folder. If you close the session and re-open the same map, the GDAL provider will not be active until the layer is visible. In my particular case, with about 1500 tiled MrSID images, this initial hit can take over a minute to process and return the map image to the viewer.

[jbirch]

I've seen this as well, but was hesitant to report it because it happened in a Fusion app and I didn't have time to track down what was causing the problem.

Jason

[jbirch]

This was/is because without a config file, the GDAL provider has to go the the source data to get its extents.

I'm not sure that MapGuide should be making whatever call it is that triggers this when the layer is initially out of scale range (perhaps there's potential for optimisation here?) but adding the raster config file in 1.2 Release makes it a lot faster.

I'd suggest that this bug be closed and, if desired, another opened to address how MapGuide loads information from layers before they are in display range.