[GRASS-user] Re: Regarding 2D Simulation Animation in Native
michael.barton at asu.edu
Sun Feb 11 22:21:39 EST 2007
The other approach might be to script what we do in the GUI.
Set up direct rendering to PPM files (GRASS environmental variable) so that
output goes to a file rather than to a display monitor. Then use a loop to
import a vector point from an ascii lookup table with xy values (you can use
conditional importing with a query to do this all in GRASS), displaying it
then overwriting it each time.
You could do this in a simple BASH shell script or in a more sophisticated
scripting language like TclTk, Python, Java, etc.
On 2/11/07 6:45 PM, "Hamish" <hamish_nospam at yahoo.com> wrote:
> yuri bay wrote:
>> I am desparately in need of your help and advice. Previously I have
>> started a very good round of discussions by enquiring about the
>> Xganim function in native binary WinGRASS. Now I need to focus on
>> getting a simulation model running, with some basic animation. My
>> objective is to make a point/marker to move from one location to
>> another on a path on a street map, i.e. vector animation. I have
>> tried Xganim, d.slide.show and d.mon, none can work! My questions
>> 1) Can this be done by updating the attribute table and refreshing
>> native WinGRASS screen?? How??
>> 2) Is there an easy way to do 1)?
> The "hardest" part is creating the individual frames. If you can do that
> manually and save each to a graphics file*, you can use any number of
> graphics encoders to make the animation. (This depends on the number of
> frames in your movie of course, for 500 frames it may take a long time
> :) You will have to search for an encoder to make the movie, I'm sure
> there are many out there for windows. MPEG/AVI movie encoders will
> probably take .ppm images, animated GIFs probably require you to convert
> individual frames into GIF first.
> [*] in the "Map Display" window, click the floppy disk icon "Export
> display to a graphics file". Choose the PPM format, name your frames
> frame0001.ppm, frame0002.ppm etc.
> (there is no save as PNG format??)
>> 3) As a contigency plan, can I install a Cygwin winGRASS and use it
>> along the native WinGRASS that I already have?
> I don't really know, but I'd think so. Try the new 6.2.1 Cygwin
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University
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