Request Tracker wrote:
this bug's URL: http://intevation.de/rt/webrt?serial_num=4917 -------------------------------------------------------------------------
Subject: ps.map: legend of vpoints sizes
Platform: GNU/Linux/x86 grass obtained from: CVS grass binary for
platform: Compiled from Sources GRASS Version: cvs_head_20060724
The sizecol option of the vpoints command in ps.map allows to make
the point symbols' size vary with the value of an attribute column. It would be great if there was some sort of legend command which
would allow to create a legend of these circle sizes. It would mean
taking the icon and scale from the vpoints command, applying the
desired legend values and positioning this legend somewhere, plus the
normal text options for the legend text.
Still thinking of how to implement this best, I am thinking along the following lines:
- add an lvalues option to the vpoints command which would take the values for which one would like to draw symbols in the legend:
i.e.: lvalues 500,2500,10000
- modify lines 216-216 in ps/ps.map/ps_vlegend.c so that it draws as many symbols as needed
Does this general idea sound reasonable, or should such a legend be drawn separately from the vlegend ?
Issues that need to be solved:
- should the symbols be drawn inside each other (easy for circles, but maybe not for others) ?
- if they are not inside each other should they be next to each other or one above the other
- if the latter, then each should probably be registered seperately in vec / nvec
- how to deal with the text: draw lines from symbols to (small) text, write values next to each other in the same order as the symbols, e.g.: o O 10 50
Hamish, as you are the ps.map expert, what do you think ?
Moritz