On 11/22/2013 02:38 PM, Chris Jackson wrote:
> Hi all
>
> I got the old Corine geotiff raster sample working with the usual select by
> click tool, but it doesn't work using select by rectangle (doesn't appear
> on the list of layers to choose).
>
> Is this by design or me just missing some configuration? Can it be done?
>
by design. You'd definitively not want a select on raster data, and it
wouldn't make much sense either. See
http://mapserver.org/input/raster.html#raster-query
and especially the sentence "Raster queries on raster layers return one
point feature for each pixel matching the query".
So a single feature is a pixel, not the pixels belonging to a class and
separated from other classes. If your selections are e.g. 5000 pixels
you would get 5000 records back to display, all with the same values...
and you'd need to create 5000 points for the highlighting layer. Also,
one would expect the full area of a homogeneous class block to be
treated as a single feature (like a single polygon) and selected
altogether, which is not feasible since every pixel is an independent.
Think about a global vegetation raster layer, just 1 by 5000 pixels
which is not really much (e.g. a Tiff with 150 MB). If a user selects
the whole world you'd select roughly 0.3 * 1 * 5000 pixels and their
values to be read pixel by pixel...
--
Shape the Mobile Experience: Free Subscription
Software experts and developers: Be at the forefront of tech innovation.
Intel(R) Software Adrenaline delivers strategic insight and game-changing
conversations that shape the rapidly evolving mobile landscape. Sign up now.
http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk
___
pmapper-users mailing list
pmapper-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/pmapper-users
