Unfortunately MapServer isn't bright enough to generate a legend solely from an image itself. The legend code just wasn't built for such a task.Sorry... Steve
2011/9/28 Jorge Arévalo <[email protected]>: > 2011/9/28 Jorge Arévalo <[email protected]>: >> I'm serving a NDVI coverage via Mapserver. So, one band, float32 >> values, [-1.0, 1.0]. I want to display the NDVI in greyscale, and >> generate a legend. I've tried 2 things: >> >> - Create two dummy classes, just for testing: >> >> CLASS >> NAME "rojo" >> EXPRESSION ([pixel] < 0.3) >> STYLE >> COLOR 255 0 0 >> END >> END >> >> CLASS >> NAME "azul" >> EXPRESSION ([pixel] >= 0.3) >> STYLE >> COLOR 0 0 255 >> END >> END >> >> So, my legend looks like this: http://dl.dropbox.com/u/6599273/leyenda.png >> >> And the image, obviously, is red and blue: >> http://dl.dropbox.com/u/6599273/capturas/ndvi_en_gvsig.png >> >> But I'd like to see the image in greyscale... The I've tried the next thing >> >> - Pre-classify values with PROCESSING "SCALE=-1.0, 1.0". I don't know >> what Mapserver internally does with this processing order, but I can >> see the image in greyscale: >> http://dl.dropbox.com/u/6599273/capturas/ndvi_gris_en_gvsig.png >> >> The problem is now I can't see any legend, because I've not created >> any class. I'd like to see all the different levels of the grayscale >> image in my legend. >> >> How could I do it? >> >> Many thanks in advance >> >> -- >> Jorge Arévalo >> Internet & Mobility Division, DEIMOS >> [email protected] >> http://es.linkedin.com/in/jorgearevalo80 >> http://mobility.grupodeimos.com/ >> http://gis4free.wordpress.com >> http://geohash.org/ezjqgrgzz0g >> > > Ok, I've found a way, but I'm sure it isn't the shortest path. > > Basically, I've generated a legend using GRASS (r.colors to add grey > color as color interpretation for band and d.legend to generate the > legend). The legend is generated from the ndvi file. So, I guess I can > create a HTML template as Mapserver legend, using the legend generated > by grass (here: > http://dl.dropbox.com/u/6599273/grass/grass_legend.png) > > On the other hand, I know how to generate a legend in Mapserver using > CLASS objects in the mapfile, but I don't know how to generate that > legend without the CLASS options in the mapfile. > > Am I taking the long way on this? Is there an easier way to generate a > legend for a NDVI file in Mapserver? > > Many thanks in advance > > -- > Jorge Arévalo > Internet & Mobility Division, DEIMOS > [email protected] > http://es.linkedin.com/in/jorgearevalo80 > http://mobility.grupodeimos.com/ > http://gis4free.wordpress.com > http://geohash.org/ezjqgrgzz0g > _______________________________________________ > mapserver-users mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-users > _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
