[GRASS5] g3d notes and possible bugs

[John Harrop]

Now the recent panic for getting products out is over I've had a chance 
to look at the cause of the problem a little more.  If I narrow down the 
region and make it completely sub-surface,  the program completes 
without any problems.  We are working with a medium size regular block 
model 134x90x60 with cells of varying size.  Some of the cells, perhaps 
10%, are air and have null values.  I've tried with and without the air 
blocks.  I would prefer to exclude them from the site file altogether, 
but I thought that perhaps s.vol.rst was failing when it tried to 
interpolate in a region of all or mostly air.

I'm now trying a 20x95x45 block well inside our data, which currently 
includes -1 values for air cells.  (All subsurface values are positive). 
 The processing reaches about 26% before failing with a segmentation 
fault.  I may well be failing to set some parameters correctly, but that 
shoudl not be causing a segmentation fault.

I gather from the man page that s.vol.rst is not doing 3d masking, but 
rather projecting a 2d mask through all the depths.  Is there a way to 
mask cells above the surface?

Command line and messages follow:

-----------------------------------------

s.vol.rst input=block3.chg elev=rst.test.2

Warning: some points outside of region -- will ignore...
Warning: strip exists with insufficient data

Processing all selected output files
will require 7600 bytes of disk space for temp files

Warning: there are points outside specified region--ignored 450036 points
Percent complete:
Warning: taking too long to find points for interpolation--please change 
the region to area where your points are

Segmentation fault

-----------------------------------------

Regards,
John Harrop


Helena wrote:

>>3)  Importing 2d elevation data does not result in the same display as
>>importing equivalent data with a 3d site approach.  I'm fairly sure the
>>fault lies in s.vol.idw - (yes, I know it was recommended that we use
>>s.vol.rst, but I have yet to get the 3d one to run without crashing.)
>>    
>>
>
>do you use the 5.0.0 version or the one in exp ? Where does it crash and
>what
>it says? It used to run OK although Jaro recently reported that the
>version
>in the 5.0.0 release gives segmentation fault if the sites
>are not exactly in the format x|y|z|#n %value (for example sites
>x|y|z|%value
>make it crash with segmentation fault which is obviously a bug but we
>did not have
>time to look into it). 
>
>thanks,
>
>Helena
> 
>  
>
>> For a smooth 3d block model the idw approach is good enough for
>>testing.  Both Z (elevation) and Y (northing) are reversed when
>>displayed after importing.  With the storage order being the reverse of
>>physical coordinates for Y and Z its not hard to accidentally reverse
>>the storage in a loop.  I think AV may have done two fixes in the code
>>that cancelled each other ;-)  I'll check that in more detail and report
>>later.
>>
>>    
>>
>
>  
>