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

Chaitanya kumar CH chaitanya.ch at gmail.com
Thu Aug 11 04:04:32 EDT 2011


What is the output of ogrinfo on the .vrt file?

2011/8/11 Mateusz Kędzior <matandked at gmail.com>

> Hi Chaitanya,
>
> I say that I don't need to create VRT file, but I was wrong. When I try to
> run ogr2ogr utility:
> *
> ogr2ogr -f GML output_file.gml input_file.csv*
>
> I discover that created file contain only table - if I choose ESRI
> shapefile as output, I get only dbf file.
>
> So i try to generate such file:
>
>
> ================================================================================
> <OGRVRTDataSource>
>     <OGRVRTLayer name="evap_OBC_OBCXYZn">
>         <SrcDataSource>evap_OBC_OBCXYZn.csv</SrcDataSource>
>
>         <GeometryType>wkbPoint</GeometryType>
>         <LayerSRS>WGS84</LayerSRS>
>         <GeometryField encoding="PointFromColumns" x="Longitude"
> y="Latitude"/>
>     </OGRVRTLayer>
> </OGRVRTDataSource>
>
> =================================================================================
>
> but:
>
>    - if I type .vrt file as input I get an empty GML file
>    - if I I type .csv file as input I get an output which contain only
>    table (without geometry)
>
> How I can run it properly?
> Which values are allowed in <GeometryField encoding> property?
> ===================
> Best regards,
> Mateusz
>
> W dniu 10 sierpnia 2011 05:58 użytkownik Chaitanya kumar CH <
> chaitanya.ch at gmail.com> napisał:
>
> 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
>>
>
>


-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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