[GRASS-user] new wxGUI Animation Tool in addons

Anna Kratochvílová kratochanna at gmail.com
Tue Oct 30 08:45:38 PDT 2012

Hi Soeren,

On Tue, Oct 30, 2012 at 2:35 PM, Sören Gebbert
<soerengebbert at googlemail.com> wrote:
> Hi Anna,
> you have implemented a great tool! I was able to visualize two space
> time raster datasets with different temporal granularity  (mixing year
> and month) synchronously. :)
> This is really cool.

Thanks to your temporal library, of course:)

> Having such a great tool raises many wishes that could be implemented
> in addition. :)
> Here just a few of them:

I've been thinking of these enhancements too. Some comments:
> * It would be great if vector time series are available to visulaize too
>   (as vector map list or space time vector datasets). So we can visualize
>   for example temperature maps and vector contours at the same
>   time in the same frame?

Of course this would make sense. To implement this, there should be a
more sophisticated way to specify layers to render - this means to
write a simplified layer manager. Another problem is the rendering -
the current rendering system in GUI is too slow to load too many maps
(therefore I currently use r.out.ppm module to write to stdout so that
it is in memory and it is not written to disk).
I also thought about adding option to load ready images. It would be
useful when you create some map composition with d.vect.chart or
similar and then you could load it in the animation tool and
optionally provide the time information as a temporal dataset which
was used for creating the charts.

> * Having a legend for the raster maps would be very handy for comparison.
>   I am preparing a tool to set the color table for a space time raster datasets
>   computed from all registered maps. So the maps of a dataset would have
>   all the same color table representing the data range of the space
> time raster dataset.

I agree that legend is definitely useful.

> * A stepper would be great to step through the time series data
>   using the lowest temporal granularity of the visualized space time datasets

I guess you mean 'next/previous frame'. Now the slider enables to
change the frame by one time unit, for example, if granularity is 2
months, the next position is +1 month. I think this behavior is more
natural but we can discuss it more.

> * Exporting animation as mp4 or similar :)

The animation tool now provides export to image sequence. I am not
sure what should be done next - I can call an external program like
ffmpeg to create a video but someone else would like to use different
program or with different parameters and also I am not sure how these
things work on Windows.
Also it would be useful to convert the images directly (without saving
images on disk) by a python library but there are two problems -
PyMedia which seems to be dead and I can't find any other, and
secondly you need to install it.
There should be probably some general module in GRASS to export video
from images - now there is r.out.mpeg only for rasters and as far as I
remember it calls some external program too.
Therefore I think that for now it could be useful (at least for
someone) to get the animation as animated GIF (with the images2gif.py
script), although GIF has many disadvantages.
Correct me if I omitted any option.

> * Starting the animation tool from comand line

I will try to implement it. Maybe there will be only a limited
functionality available from the command line.

> I have prepared some datasets which you can play with:
> http://www-pool.math.tu-berlin.de/~soeren/tmp/

Thank you very much, I will have a look.


> These datasets are derived form the ECA&D project E-OBS gridded data[1].
> Usage policy od ECAD data is available here [2].
> You can simply import the datasets in a Lat/lon location using t.rast.import.
> Best regards
> Soeren
> [1] http://eca.knmi.nl/download/ensembles/ensembles.php
> [2] http://eca.knmi.nl/documents/ECAD_datapolicy.pdf
> 2012/10/19 Anna Kratochvílová <kratochanna at gmail.com>:
>> Hi all,
>> I would like to announce that new wxGUI Animation Tool is available
>> for testing in GRASS 7 Addons. You can install it with the g.extension
>> dialog (or in the command line: g.extension -s
>> extension=wx.animation). You can animate a series of raster maps or
>> better, a space time raster dataset created by the new GRASS 7
>> temporal framework.
>> Please, have a look at the videos on the wiki page [1] and the manual
>> page. I would like to demonstrate the functionality on some more
>> interesting data which I don't have, so I would be glad if someone
>> could help.
>> Best,
>> Anna
>> [1] http://grass.osgeo.org/wiki/WxPython-based_GUI_for_GRASS#Animation_Tool
>> _______________________________________________
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