[Gvsig_english] xyz data

[Angus Jeffery]

Ben

Here are the first few lines of the data, which is basically a 10m
elevation grid in British National Grid:

north:121750
south:96750
east:258025
west:233025
rows:6275026
cols:3
280000,100000,94
280000,100010,97.6
280000,100020,101.3
280000,100030,103.5
280000,100040,105.4
280000,100050,107.4


Line 2091676: 261020,87520,499.6

Log:
Sun, 03-Jun-2012 15:39:49 GRASS: r.in.ascii input="D:\LANDSCAPE
VISUAL\01_JOBS\Aardvark EM\North
Beer\04_Received\OS_Landform_Profile_DTM_ASCII_XYZ_167655_248228\OS_Profile_head.xyz"
title=OS_Profile mult="1.0 or read from header" nv="* or read from
header" output=output[TMP] --overwrite
Sun, 03-Jun-2012 15:39:49 GRASS:
Sun, 03-Jun-2012 15:39:57 GRASS:
Sun, 03-Jun-2012 15:40:11 GRASS: ERROR: Data conversion failed at row
2091676, col 1
Sun, 03-Jun-2012 15:40:11 GRASS:

None of the option boxes were checked. For the output extent, I simply
put the extent of the data, i.e. N/S/E/W as stated in the header
above, with 10 cell size. I ran a few times and it always stops at the
line 2091676.

Thanks
Angus

On 3 June 2012 14:25, Benjamin Ducke <benducke at fastmail.fm> wrote:
> Hi Angus, please post: (a) an excerpt of
> two or three lines of your input data, (b) the names
> and values of all options you used to run r.in.ascii
> (you can get the complete command line from the
> SEXTANTE log viewer, page "GRASS output"), and (c)
> the offending line #2091676.
>
> There is no significant memory limitation for
> r.in.ascii, as it only rasterizes one point at
> a time.
>
> Cheers,
>
> Ben
>
>
> On 06/03/2012 02:00 PM, Angus Jeffery wrote:
>> Hi Ben
>> Thanks for such a quick reply. I created the required header rows for
>> r.in.ascii and but when I run it I am getting a consistent error
>> message: "Data conversion failed at row 2091676, col 1". I looked at
>> the data in this row and there is nothing different to any other
>> record. Could this be a memory issue, is there a limit to how many
>> points can be processed this way? What else should I check?
>> Best regards
>> Angus
>>
>> On 3 June 2012 11:47, Benjamin Ducke<benducke at fastmail.fm>  wrote:
>>> Use the r.in.ascii GRASS module from within
>>> SEXTANTE to directly rasterize the data.
>>> That way, you can deal with millions of data
>>> points without having to go through memory
>>> and CPU intensive operations, such as building
>>> vector points and interpolating them back to
>>> a raster.
>>>
>>> Ben
>>>
>>> On 06/03/2012 12:17 PM, Angus Jeffery wrote:
>>>> Morning
>>>> I want to work out an effective workflow for getting a large quantity
>>>> of ascii .xyz data (point elevation data) into gvSIG - I estimate
>>>> roughly 7 million points, with end use intended to be raster map in
>>>> gvSIG or vector for export to other software (e.g. .dxf file showing
>>>> elevation contours). Has anyone undertaken a similar task or does
>>>> anyone have any ideas of a sensible workflow using gvSIG/grass modules
>>>> please?
>>>> As an alternative to using all the data, does gvSIG have an effective
>>>> way of subsampling, so reducing the data to be processed and speeding
>>>> up the process, accepting lower accuracy?
>>>> Best regards
>>>> Angus
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>>>
>>>
>>>
>>> --
>>> Benjamin Ducke
>>> {*} Geospatial Consultant
>>> {*} GIS Developer
>>>
>>>    benducke at fastmail.fm
>>> _______________________________________________
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>
>
> --
> Benjamin Ducke
> {*} Geospatial Consultant
> {*} GIS Developer
>
>   benducke at fastmail.fm
> _______________________________________________
> Gvsig_internacional mailing list
> Gvsig_internacional at listserv.gva.es
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>
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