On Fri, Aug 14, 2009 at 8:44 AM, Rahkonen Jukka<[email protected]> wrote: > Frank Warmerdam wrote: > > Rahkonen Jukka wrote: >>> Hi, >>> >>> If have overlapping images from different years. Can I control in some >>> easy and reliable way that the new images will get drawn on top, for >>> example by writing tileindex shapefiles so that new images have bigger >>> fid values? > >>Jukka, > >> The order of images in the tileindex shapefile will be the order >> they are drawn - if - you do not build a spatial index on the >> shapefile. If you have a spatial index the drawing order >> becomes essentially random, and of course if you have a lot >> of images a spatial index is quite valuable. > > Damn, I need spatial index for sure. Any idea about how to get them both? > Perhaps taking tile index with ordered query from Oracle, PostGIS or even > SpatiaLite?
Jukka, I have dug deeper and I'm afraid I mislead you. It turns out that both the MapServer shapefile code and OGR inherently sort the results of the spatial index query so shapes are always returned in order. In OGR a sort is done explicitly while in MapServer selected shapes are tracked in a bit vector so they are always sorted in the end. I have not experimented, so you should confirm, but it should be sufficient to order the index entries based on the order you want things drawn. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [email protected] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
