[gdal-dev] OGRLayer.Intersection() question

[Dheeraj Reddy Mamidi]

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 but I
>>> 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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