[mapserver-users] Re: Mapserver + NDVI styling

[Jorge Arévalo]

Yes, it does it in that way. I have no problem with this. But I need a
legend for the image. After reading the response from Steve Lime, I
think I'll generate the image with GRASS, to include it in the HTML
template.

And all replies are welcome :-). Thanks.

2011/9/28 Gustavo <gus.fava at gmail.com>:
> I'm not sure but if you just display your raster without any styling i think
> MapSever would show it in grayscale.
>
> I'm new with MapServer so i'm feeling a bit insolent posting a reply :)
>
>
> El 28 de septiembre de 2011 11:30, Jorge Arévalo
> <jorge.arevalo at deimos-space.com> escribió:
>>
>> 2011/9/28 Jorge Arévalo <jorge.arevalo at deimos-space.com>:
>> > 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
>> > jorge.arevalo at deimos-space.com
>> > 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
>> jorge.arevalo at deimos-space.com
>> http://es.linkedin.com/in/jorgearevalo80
>> http://mobility.grupodeimos.com/
>> http://gis4free.wordpress.com
>> http://geohash.org/ezjqgrgzz0g
>> _______________________________________________
>> mapserver-users mailing list
>> mapserver-users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
>



-- 
Jorge Arévalo
Internet & Mobility Division, DEIMOS
jorge.arevalo at deimos-space.com
http://es.linkedin.com/in/jorgearevalo80
http://mobility.grupodeimos.com/
http://gis4free.wordpress.com
http://geohash.org/ezjqgrgzz0g