[gdal-dev] OGRLayer.Intersection() question

[Tamas Szekeres]

Dheeraj,

I noticed you are talking about the layer level geometry functions, which
hasn't been updated in the C# bindings yet. I'll add the necessary
implementation shorly. Also added a ticket to track the changes:
http://trac.osgeo.org/gdal/ticket/5264

Best regards,

Tamas




2013/10/10 Dheeraj Reddy Mamidi <drmamidi at rothwellgroup.com>

> Tamas,
>
> Sorry the sample code had wrong data source names. Here is the corrected
> sample code..
>
>
> var spatialReference = new OSGeo.OSR.SpatialReference("");
> spatialReference.ImportFromProj4("+proj=longlat +ellps=WGS84 +datum=WGS84
> +no_defs");
>
> var driver = OSGeo.OGR.Ogr.GetDriverByName("ESRI Shapefile");
>
> DataSource dataSourceToIntersectOn =
> driver.Open(@"C:\Temp\gdal_32\Polygon.shp", 0);
> Layer layerToIntersectOn = dataSourceToIntersectOn.GetLayerByIndex(0);
>
> DataSource dataSourceToIntersect =
> driver.Open(@"C:\Temp\gdal_32\Polyline.shp", 0);
> Layer layerToIntersect = dataSourceToIntersect.GetLayerByIndex(0);
>
> var intersectedShapeData = driver.CreateDataSource(@"C:\Temp\gdal_32", new
> string[] { });
> wkbGeometryType wkbGeometryType =
> layerOriginal.GetLayerDefn().GetGeomType();
> Layer intersectedLayer = intersectedShapeData.CreateLayer("intersection",
> spatialReference, wkbGeometryType, new string[] { });
>
> OSGeo.OGR.SWIGTYPE_p_void callback_data = new
> OSGeo.OGR.SWIGTYPE_p_void(new IntPtr(5), false, layerToIntersect);
>
> OSGeo.OGR.SWIGTYPE_p_GDALProgressFunc callback = new
> SWIGTYPE_p_GDALProgressFunc(new IntPtr(5), false, layerToIntersect);
>
> layerToIntersect.Intersection(layerToIntersectOn, intersectedLayer, new
> string[] { "SKIP_FAILURES=YES" }, callback, callback_data); // Line where
> it fails
>
>
> Thanks,
> Dheeraj
>
>
> On Thu, Oct 10, 2013 at 1:16 PM, Dheeraj Reddy Mamidi <
> drmamidi at rothwellgroup.com> wrote:
>
>> Hi Tamas,
>>
>> Thanks for your response. In fact I don't require progress notification,
>> but I am not able to ignore those arguments (pass them as null). If I pass
>> them as null I get error "Attempt to dereference null GDALProgressFunc". If
>> I just pass those arguments initializing them they way I am doing below in
>> the sample code, I get  "Attempted to read or write protected memory.
>> This is often an indication that other memory is corrupt." error.
>>
>> I am using Gdal 1.10 library.
>>
>> Here is the sample code..
>>
>> var spatialReference = new OSGeo.OSR.SpatialReference("");
>> spatialReference.ImportFromProj4("+proj=longlat +ellps=WGS84 +datum=WGS84
>> +no_defs");
>>
>> var driver = OSGeo.OGR.Ogr.GetDriverByName("ESRI Shapefile");
>>
>> DataSource dataSourceToIntersectOn =
>> driver.Open(@"C:\Temp\gdal_32\Polygon.shp", 0);
>> Layer layerToIntersectOn = dataSourceCookieCutter.GetLayerByIndex(0);
>>
>> DataSource dataSourceToIntersect =
>> driver.Open(@"C:\Temp\gdal_32\Polyline.shp", 0);
>> Layer layerToIntersect = dataSourceOriginal.GetLayerByIndex(0);
>>
>> var intersectedShapeData = driver.CreateDataSource(@"C:\Temp\gdal_32",
>> new string[] { });
>> wkbGeometryType wkbGeometryType =
>> layerOriginal.GetLayerDefn().GetGeomType();
>> Layer intersectedLayer = intersectedShapeData.CreateLayer("intersection",
>> spatialReference, wkbGeometryType, new string[] { });
>>
>> OSGeo.OGR.SWIGTYPE_p_void callback_data = new
>> OSGeo.OGR.SWIGTYPE_p_void(new IntPtr(5), false, layerToIntersect);
>>
>> OSGeo.OGR.SWIGTYPE_p_GDALProgressFunc callback = new
>> SWIGTYPE_p_GDALProgressFunc(new IntPtr(5), false, layerToIntersect);
>>
>> layerToIntersect.Intersection(layerToIntersectOn, intersectedLayer, new
>> string[] { "SKIP_FAILURES=YES" }, callback, callback_data); // Line where
>> it fails
>>
>>
>> The data that I am trying to intersect (shapefiles are attached).
>>
>>
>> Thanks,
>> Dheeraj
>>
>>
>>
>>
>>
>> On Thu, Oct 10, 2013 at 12:33 PM, Tamas Szekeres <szekerest at gmail.com>wrote:
>>
>>> Dheeraj,
>>>
>>> I don't think the OSGeo.OGR.Layer.Intersection supports progress
>>> notification. You might probably have encountered a bug which should be
>>> fixed. Do you have a sample code to reproduce this issue? I would
>>> specifically interested in the actual geometries have been passed to the
>>> function.
>>>
>>> Best regards,
>>>
>>> Tamas
>>>
>>>
>>>
>>> 2013/10/10 Dheeraj Reddy Mamidi <drmamidi at rothwellgroup.com>
>>>
>>>> Hi list,
>>>>
>>>>  I have troubles with C# bindings of OGR. I was trying to perform
>>>> intersection on two feature classes (shape file formats) using
>>>> OSGeo.OGR.Layer.Intersection(), but have problems making it work. I
>>>> keep getting an error saying "AccessViolationException was unhandled.
>>>> Attempted to read or write protected memory. This is often an indication
>>>> that other memory is corrupt.
>>>>
>>>> Is the above error something to do with SWIGTYPE_p_GDALProgressFunc
>>>> callback and OSGeo.OGR.SWIGTYPE_p_void callback_data arguments? I
>>>> tried passing those parameters null as suggested by some in the forums butI keep getting the error "Attempt to dereference
>>>> null GDALProgressFunc". I am not sure what that means.
>>>>
>>>> And when I instantiate callback as new SWIGTYPE_p_GDALProgressFunc()
>>>> and new callback_data as new SWIGTYPE_p_void(), I don't get error Attempt
>>>> to dereference null GDALProgressFunc, but still have error saying AccessViolationException
>>>> was unhandled. Attempted to read or write protected memory. This is often
>>>> an indication that other memory is corrupt.
>>>>
>>>> Can someone please help me figure this out and let me know how to make
>>>> use of OSGeo.OGR.Layer.Intersection() in the right way with c#
>>>> bindings. Thank you.
>>>>
>>>> Thanks,
>>>> Dheeraj
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> gdal-dev mailing list
>>>> gdal-dev at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>>
>>>
>>>
>>
>>
>> --
>>
>>
>
>
> --
> Dheeraj Reddy Mamidi
>
>
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