[GRASS5] New thematic mapper for GRASS 6

[Moritz Lennert]

On Wed, May 11, 2005 21:14, Michael Barton said:
>> From: Moritz Lennert <mlennert at club.worldonline.be>

>> - One problem I encounter sometimes (still trying to figure out the exact
>> sequence leading to this) is the following error:
>>
>> /usr/local/grass-6.1.cvs/scripts/d.vect.thematic: line 143: TMP1: Permission
>> denied
>
> I am using g.temp to generate a TMP file ID and create a TMP file to hold
> data needed to calculate stats. This is actually taking place in v.univar.sh
> and would be unnecessary if v.univar can be fixed/upgraded. I'm using the
> format that is required for proper security in creating temporary files. I'm
> guessing that there is a problem on your system in writing a file in the
> appropriate locale. Is there possibly another TMP1 already created (by
> another process) and in use in this area?

Must be something like this, but I haven't been able to pin it down, yet. And
unfortunately I won't have much time for testing in the next few days...

>>
>> - The options available in the key "type" should be reduced to the only
>> sensible ones (point, centroid, area) as the others don't seem to work (or I
>> misunderstood something); also it might be useful to print a warning if the
>> type of thematic map display is set to "graduated points" and the vector map
>> type to "area" and vice versa. Currently the program runs, but nothing shows
>> up.
>>
>
> In fact, lines and boundaries should also display with graduated colors
> here. So they do make sense. I haven't tested it with lines yet however.

Sorry, my error. yes it seems to work well with lines. Haven't had the time to
try with boundaries...

>
>>
>> - Concerning the legend: it would be good to have a precise indication of
>> where one category ends and the other starts. At the moment, it prints
>> something like
>>
>> 1.000000-3.2725    5
>> 3.2725-5.545    7
>> 5.545-7.8175    9
>> 7.8175-10.09    11
>
> The algorithm specifies the range (given above) then looks for records > 1st
> number and <= 2nd number. I understand what you are wanting to do, but not
> sure how to do it. I'll see if I can figure out something as I refine this.

I think it is mostly a question of display. Something like this might already
be alright:

[1.000000-3.2725]    5
]3.2725-5.545]    7
]5.545-7.8175]    9

>
>>
>> And just to prove once again that users are a terribly ungrateful bunch and
>> always want more, here a few wishes:
>>
>> - I think one useful addition would be the possibility to display the
>> available columns, or, even better, to chose from a list of available
>> columns.
>
> I'd love to do this, but don't know how to program this in the existing
> g.parser interface via shell scripting at the moment.
>

Sorry, can't help you there.


>> - It was very easy for me to very quickly create a new color scheme (here we
>> use blue for low values and red for high values...) in the script. That's
>> very
>> useful for those of us who are not afraid of going into the code. But it
>> would
>> be interesting to see if there is a way to offer a color choser to chose the
>> min and max color and to automatically calculate the intermediate values.
>> Another great option would be to also be able to chose all the colors
>> manually...
>
> I'd also like a color chooser (kind of like in r.colors rules). I have an
> idea of how this might be accomplished. I don't know if this would make it
> harder (i.e., too complicated) or easier for most people to do.
>
> I thought about a manual color chooser, but realized that by making a group
> in the GIS Manager and duplicating a vector display line, there is already a
> much better interface for doing this than I could do in a script.

I'm not sure I understand exactly what you mean by this, but it seems more
complicated, as you have to define the where clause in each line, whereas
d.vect.thematic calculates the intervals automatically.

Another cool feature would be the possibility to enter interval boundaries
manually...

Moritz