[GRASS-user] generalize a map of points

[Wolf Bergenheim]

On 18.10.2008 02:30, José María Michia wrote:
> But my map has many elements. It is necessary to
> suppress some labels, or some points.

Yes, v.label.sa doesn't suppress any labels. That is also the main
difference between PAL and v.label.sa. v.label.sa assumes that you want
to display all labels. I have plans of adding a few other features to it.

Another main difference between PAL and the v.label.sa algorithm is the
way to find an optimum solution. v.label.sa uses Simulated Annealing,
which is based on randomness. PAL on the other hand uses chained
transformations which to my understanding means that you take a label
and if it is overlapping, you move it to another candidate place. If it
overlaps with exactly one other label then you move that label and the
chain goes on until you move a label to overlap with multiple labels in
which case you choose not to display that label, and stop the recursion.
The best visited configuration is selected as the new. I still have to
read the papers they refer to, but it seems like a nice approach. A bit
different from the SA one.

I feel that allowing a user to select which labels to show is more
powerful than having an algorithm drop labels off.

1) Allow a where argument which allows you to select features to label
2) Allow multiple maps
3) Add support for labeling of areas. (currently labels areas as point
                                       labels around centroid)

--Wolf

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<:3 )---- Wolf Bergenheim ----( 8:>