[GRASS-user] generalize a map of points

[José María Michia]

2008/10/18 Wolf Bergenheim <wolf+grass en bergenheim.net>:
> 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

If possible, I think it would be useful feature the following:

- Where two labels overlap, comparing an attribute to decide which one stays

For example: on a map of cities you can use the number of inhabitants.
If the city "A" has more inhabitants than the city "B", maintaining
the label of the city "A".

José María

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