[GRASS-user] v.surf.idw G_Malloc

Mon Jan 14 12:55:44 EST 2008

Hi Paul - thanks for the fast reply.

Ok - my import command is -

v.in.ascii input=/home/Matthew/XYGrp45.csv output=vectorOut format=point
fs=, skip=0 'columns=x double precision, y double precision, yield double
precision' x=2 y=1 z=3 cat=0

output of that command is -

Maximum input row length: 28
Maximum number of columns: 3
Minimum number of columns: 3
Building topology ...
Registering lines:    1000          2000          3000          4000
5000          6000          7000          8000          9000         10000
11000         12000         13000         14000         15000         16000
17000         18000         19000         20000         21000         22000
23000         24000         25000         26000         27000         28000
29000         30000         31000         32000         33000         34000
35000         36000         37000         38000         39000         40000
41000         42000         43000         44000         45000         46000
47000         48000         49000         50000         51000         52000
53000         54000         55000         56000         57000         58000
59000         60000         61000         62000         63000         64000
65000         66000         67000         68000         69000         70000
71000         72000         73000         74000         75000         76000
77000         78000         79000         80000         81000         82000
83000         84000         85000         86000         87000         88000
89000         90000         91000         92000         93000         94000
95000         96000         97000         98000         99000        100000
101000        102000        103000        104000        105000        106000
107000        108000        109000        110000        111000        112000
113000        114000        115000        116000        117000        118000
119000        120000        121000        122000        123000        124000
125000        126000        127000        128000        129000        130000
131000        132000        133000        134000        135000        136000
137000        138000        139000        140000        141000        142000
143000        144000        145000        146000        147000       
147909 primitives registered      
Building areas: 

0 areas built      
0 isles built
Attaching islands: 
Attaching centroids: 

Topology was built.
Number of nodes     :   147872
Number of primitives:   147909
Number of points    :   147909
Number of lines     :   0
Number of boundaries:   0
Number of centroids :   0
Number of areas     :   0
Number of isles     :   0

MY SURF.IDW COMMAND -

v.surf.idw input=vectorOut output=rasterOut npoints=12 column=3

Output - G_Malloc - Out of Memory

Cheers,

Matt

-----Original Message-----
From: Paul Kelly [mailto:paul-grass at stjohnspoint.co.uk] 
Sent: Tuesday, 15 January 2008 2:59 AM
To: Matthew James
Cc: grass-user at lists.osgeo.org
Subject: Re: [GRASS-user] v.surf.idw G_Malloc

On Tue, 15 Jan 2008, Matthew James wrote:

> Hi Everyone,
>
>
>
> New grass user J I?m using Grass 6.2.3 on windows using cygwin.
>
>
>
> I am trying to generate yield maps. I have csv files containing x, y and
> yield columns.
>
>
>
> The yields are calculated at random spots around the paddock.
>
>
>
> In general these files can be many thousands of points long.
>
>
>
> I?m first importing them into a vector file using v.in.ascii (seems to me
> that the process of importing such files needs to be documented better ?
> it?s hellish for a new user)
>
>
>
> When I try to run v.surf.idw I get a ?G_Malloc ? out of memory error? ?
this
> occurs almost instantaneously.

Please give the exact command lines you used for v.in.ascii and v.surf.idw 
as it is a bit hard to see what you are doing otherwise (also run 
v.surf.idw with --verbose in case it generates any useful messages).

Also are you importing the yield value as a z co-ordinate or a database 
field? For large numbers of points in general performance will be much 
much better if you avoid the database connection.

Also not building topology during the import (check the v.in.ascii man 
page; I can't remember the exact flag to use) will give a big performance 
boost for a large number of points. Unfortunately the version of 
v.surf.idw in 6.2.3 requires topology to be built to run - if you upgrade 
to 6.3 this is not required and you have a much better chance of being 
successfully able to interpret huge datasets with v.surf.idw.

Paul

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