[GRASS-dev] Speed map display in wxGUI on bigger monitors

GRASS GIS GRASS GIS developer
1

Hi,

when working with the wxGUI on bigger monitors, it is rather slow
when it comes to map display.
Looking into the /tmp/ directory, I find fairly huge files which are
generated and then combined for display.
It is getting even worse when using GRASS over network.

Question: why the uncompressed PNM/PPM format used by g.pnmcomp?

Markus

2

On Fri, Aug 3, 2012 at 4:19 PM, Markus Neteler <neteler@osgeo.org> wrote:

Hi,

when working with the wxGUI on bigger monitors, it is rather slow
when it comes to map display.
Looking into the /tmp/ directory, I find fairly huge files which are
generated and then combined for display.
It is getting even worse when using GRASS over network.

Question: why the uncompressed PNM/PPM format used by g.pnmcomp?

... I am still interested to understand this...

thanks
Markus

3

Markus wrote:

Question: why the uncompressed PNM/PPM format used by g.pnmcomp?

because it is less CPU intensive, at the cost of bigger disk I/O.

ssh -C works wonders on a slow network, but how big are the files
you are talking about?

did the MS Windows bug where those temp files were never
deleted from %TEMP% ever get fixed? I don't remember that
it did..

Hamish

4

On Mon, Aug 13, 2012 at 10:24 PM, Hamish <hamish_b@yahoo.com> wrote:

Markus wrote:

Question: why the uncompressed PNM/PPM format used by g.pnmcomp?

because it is less CPU intensive, at the cost of bigger disk I/O.

I start to wish the opposite!

ssh -C works wonders on a slow network, but how big are the files
you are talking about?

Between 1 and 10MB easily (and the GUI generates several of them).

did the MS Windows bug where those temp files were never
deleted from %TEMP% ever get fixed? I don't remember that
it did..

Sometimes temp files are leftover. In any case they should go into
mapset/.tmp/ and not into the system /tmp IMHO.

Markus

5

Markus Neteler wrote:

when working with the wxGUI on bigger monitors, it is rather slow
when it comes to map display.
Looking into the /tmp/ directory, I find fairly huge files which are
generated and then combined for display.
It is getting even worse when using GRASS over network.

Question: why the uncompressed PNM/PPM format used by g.pnmcomp?

The original reason was that Tk doesn't support PNG.

That isn't relevant to the wxPython GUI. But the wxPython GUI should
really be doing its own compositing rather than relying upon
g.pnmcomp.

--
Glynn Clements <glynn@gclements.plus.com>