[gdal-dev] save raster as point-vector file

[Chaitanya kumar CH]

Mateusz,

You have to change the OGRVRTLayer name property to point to the file name
without the extension.  Also change the SrcDataSource element.

FYI, this process creates a vector file with points. gdal_polygonize
produces polygons.

2011/8/10 Mateusz Kędzior <matandked at gmail.com>

> Hi again,
>
> is it mandatory to create such file?
> Regarding to information on GDAL/OGR page should I create simple text file
> which contains only other OGRVRTLayer name property :
>
> <OGRVRTDataSource>
>     <OGRVRTLayer name="test">
>         <SrcDataSource>test.csv</SrcDataSource>
>         <GeometryType>wkbPoint</GeometryType>
>         <LayerSRS>WGS84</LayerSRS>
>         <GeometryField encoding="PointFromColumns" x="Longitude" y="Latitude"/>
>     </OGRVRTLayer>
> </OGRVRTDataSource>
>
> ==============
> Best regards,
> Mateusz
>
> W dniu 9 sierpnia 2011 20:13 użytkownik Chaitanya kumar CH <
> chaitanya.ch at gmail.com> napisał:
>
>> Create a text file with just the header. Use the cat command to join this
>> file and the xyz file.
>> $ cat HeaderFile.csv file1.csv > file1.cHi sv
>>
>> You can repeat this on all files in a shell script.
>>
>> Otherwise add the following line in the gdal2xyz.py script at line 144
>> [1].
>>
>> dst_fh.write( 'Longitude,Latitude,Name' )
>>
>> You will also have to create a separate vrt file for each csv file. The
>> SrcDataSource element value changes for each file.
>>
>> [1]:
>> http://trac.osgeo.org/gdal/browser/trunk/gdal/swig/python/scripts/gdal2xyz.py?rev=21127#L145
>>
>>
>> 2011/8/9 Mateusz Kędzior <matandked at gmail.com>
>>
>>> Chaitanya,
>>>
>>> if I understand properly, I need to add one line to each of processed
>>> files.
>>> How I can do it quickly? Is there any option in gdal2xyz.py script?
>>>
>>> If no - what would You recommend?
>>> I think about sed utility, but it's general difficult in use.
>>>
>>> When I am thinking about Python I see only one possibility - load each
>>> file to variable and then assign to another first line plus variable and at
>>> last - save it.
>>>
>>> ==============
>>> Best Regards,
>>> Mateusz
>>>
>>> W dniu 9 sierpnia 2011 13:38 użytkownik Chaitanya kumar CH <
>>> chaitanya.ch at gmail.com> napisał:
>>>
>>> Mateusz,
>>>>
>>>> gdal2xyz.py creates space delimited fields. Consider running it with the
>>>> -csv option to delimit it with comma.
>>>> Now you can almost use it as a csv format vector file. You just need to
>>>> add a header row and define a small VRT file as described in OGR's CSV
>>>> driver page[1].
>>>> Run ogrinfo and ogr2ogr on the .vrt file to check the file.
>>>>
>>>> [1]: http://www.gdal.org/ogr/drv_csv.html
>>>>
>>>> 2011/8/9 Mateusz Kędzior <matandked at gmail.com>
>>>>
>>>>> Hello,
>>>>>
>>>>> I would like to show value of each raster cell as label. My idea (I
>>>>> don't know any plugin or any functionality in GDAL/OGR which allow to do it
>>>>> easier) is to export raster using gdal2xyz.py into coordinates-value format
>>>>> and then save it as vector (GML or shapefile). For this second task, I try
>>>>> to use
>>>>>
>>>>> =================================================================================================================================================
>>>>> gdal_polygonize.py:
>>>>> gdal_polygonize.py rainfXYZ.txt rainf.shp Creating output rainf.shp of
>>>>> format GML. 0...10...20...30...40...50...60...70...80...90...100 - done.
>>>>>
>>>>> =================================================================================================================================================
>>>>> unfortunately I am unable to load created file (even if I change the
>>>>> extension to .gml)
>>>>> ogr2ogr tool don't even recognize this format.
>>>>>
>>>>> =========================
>>>>> Thank You in advance,
>>>>> Mateusz
>>>>>
>>>>> _______________________________________________
>>>>> gdal-dev mailing list
>>>>> gdal-dev at lists.osgeo.org
>>>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards,
>>>> Chaitanya kumar CH.
>>>>
>>>> +91-9494447584
>>>> 17.2416N 80.1426E
>>>>
>>>
>>>
>>
>>
>> --
>> Best regards,
>> Chaitanya kumar CH.
>>
>> +91-9494447584
>> 17.2416N 80.1426E
>>
>
>


-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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