[Gvsig_english] xyz data

[Benjamin Ducke]

Sorry, the correct command is actually
r.in.xyz. To get your data read in correctly
you will have to at least set the field
separator (option "fs") to , (comma).

Also, your first six
lines are header information. You might be
able to just skip over them with the "-i"
flag.

Ben


On 06/03/2012 04:51 PM, Angus Jeffery wrote:
> 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
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>> Gvsig_internacional mailing list
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-- 
Benjamin Ducke
{*} Geospatial Consultant
{*} GIS Developer

   benducke at fastmail.fm