wish: logarithmic legend for raster maps
|Reported by:||veroandreo||Owned by:|
|Keywords:||d.legend, gsoc2016, cartography||Cc:|
I have several raster maps of chlorophyll concentration (mg/m3) with mostly very small values (from 0.02 to 1.5) and few high values (between 20 and 100). When I use d.legend, as it linearly scales values from minimum to maximum, I cannot see variation in colors in those values I'm interested most, but the gradient almost only shows variation in higher values, which again, are the minority (see file attached).
Wish: A flag for logarithmic display of legend values or at least the possibility to set tick marks at desired values, i.e.: 0.01,0.1,1,10,100 (without loosing the continuos gradient, as in #1147) would be really appreciated in terms of visualization.
Hint: r.colors with logarithmic flag or transforming the raster to logarithm does not solve this issue, and one may not be interested in the logarithm of the variable, either, but just getting a good visualization of colors.
The problem is also seen in the manual of r.flow (http://grass.osgeo.org/grass71/manuals/r.flow.html#example). The third map is mostly "yellowish" but that color does not appear in the legend.
Thanks much in advance! Vero