[gdal-dev] save raster as point-vector file
Chaitanya kumar CH
chaitanya.ch at gmail.com
Fri Aug 12 09:15:02 EDT 2011
Mateusz,
Refer to OGR's VRT format driver page.
http://www.gdal.org/ogr/drv_vrt.html
2011/8/11 Mateusz Kędzior <matandked at gmail.com>
> Hi Chaitanya,
>
> I try to add full path to csv file - is it correct?
>
> ===================================================NEW VRT
> FILE====================================
> <OGRVRTDataSource>
> <OGRVRTLayer name="evap_OBCXYZn">
>
> <SrcDataSource>"/media/windows/studia/2_sem_mgr/mgr/prof_Zawadzki/dods/gldas/00Z07Apr2009_00Z15Apr2009/evap_OBCXYZn.csv"</SrcDataSource>
>
> <GeometryType>wkbPoint</GeometryType>
> <LayerSRS>WGS84</LayerSRS>
> <GeometryField encoding="PointFromColumns" x="Longitude"
> y="Latitude"/>
> </OGRVRTLayer>
> </OGRVRTDataSource>
>
> ================================================================================================
>
> When I try use ogrinfor I get an error message:
>
> FAILURE:
> Unable to open datasource `evap_OBCXYZn.vrt' with the following drivers.
>
> When I use the same tool at csv file I get:
>
> =================================
>
> INFO: Open of `evap_OBCXYZn.csv'
> using driver `CSV' successful.
> 1: evap_OBCXYZn (None)
>
> ================================
>
> The CSV file contain such information:
>
> ============================
> Longitude,Latitude,Name
> 20.132145,52.4227439,1.78132e-05
> 20.382145,52.4227439,1.89083e-05
> ...
> and so on..
> ============================
>
> How I can change it to get vector-point layer? As I wrote I can only get a
> layer without geometry if I point to csv file.
>
> ============
> Best regards,
> Mateusz
>
>
>
> W dniu 11 sierpnia 2011 10:04 użytkownik Chaitanya kumar CH <
> chaitanya.ch at gmail.com> napisał:
>
> 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
>>
>
>
--
Best regards,
Chaitanya kumar CH.
+91-9494447584
17.2416N 80.1426E
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