Hi Armin Been off-grid for a bit, thanks for clarifying. I appreciate it is selection of pixels, this may be still useful in some situations for smaller local areas. I am dealing with model outputs (to date mainly rectilinear->polygon features), though may now be dealing with rasterised flexi-mesh grids instead and trying to maintain the level of data accessibility where possible. I wonder whether I need to grab selection extents and query a separate points feature class instead.
Cheers Chris On 22 November 2013 18:17, Armin Burger <armin.bur...@gmail.com> wrote: > 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 10000 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 * 10000 * 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 > ------------------------------------------------------------------------------ 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
