[GRASS5] r3.showdspf problems in GRASS 5.7

Glynn Clements glynn.clements at virgin.net
Wed Aug 25 04:11:26 EDT 2004

Michael Barton wrote:

> I tried again to get r3.showdspf to work without success. I am using the
> sample weather dataset and Lorenzo Moretti's binaries under Mac OSX 10.3.5
> Problem #1. When I run r3.showdspf via g_gui(), it sends output to the tcltk
> output display window--as expected. However, it needs to send output to an
> xterm so that you can interact with it. I can script around this in
> tcltkgrass menus, but thought I would mention it.

Right. I guess that the parser interface needs another function to
indicate that the program needs a terminal. This would need to be
communicated to the Tcl code (e.g. via an additional argument to

> Problem #2. Potentially more serious. When I run r3.showdspf from the
> command line 
> >>r3showdspf grid3=CloudLCP.992172300 dspf=test
> I get the desired prompt. But when I enter any of the normal r3.showdspf
> commands (e.g., +, -, d, ?) I get a "Broken pipe" error.

Has the child process (which actually does the work) crashed?

r3.showdspf fork()s; the parent just runs a loop, printing the prompt,
reading a line of input, and sending it to the child. The child does
everything else. If the child dies, the parent will receive SIGPIPE
the next time it writes to the pipe.

> I also get errors when I try to run r3.mkdspf. This generates many errors.
> For example....
> GRASS 5.7.cvs:~ > r3.mkdspf grid3=CloudLCP.992172300 dspf=cloudtest2 tnum=7
> Region from getWindow: 80 100 21
> ** cloudtest2 exists. ok to overwrite? (y/n) [n] y
> rows=80 cols=100 depths=21
> threshold values: 0.000000 0.183333 0.366667 0.550000 0.733333 0.916667
> 1.100000
> No. of thresholds: 8
> DSPF DIMS: 80 100 21
> Writing cloudtest2 from CloudLCP.992172300...display file completed:ERROR:
> G_fpcompress_readXdrNums: read error

This indicates that G_zlib_read() returned an error. You can't
realistically determine anything else without using a debugger.

Although: are you sure that the grid3d file is valid?

Glynn Clements <glynn.clements at virgin.net>

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