[Gvsig_english] xyz data

[Angus Jeffery]

Hi Ben
Many thanks, I got this working. It's a useful tool.
Kind regards
Angus

On 3 June 2012 19:18, Benjamin Ducke <benducke at fastmail.fm> wrote:
> 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
>>> _______________________________________________
>>> Gvsig_internacional mailing list
>>> Gvsig_internacional at listserv.gva.es
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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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