Invalid Polygon Issue

[Em3a-c]

Hi all,

I've been using your library recently, it's really nice and easy to use!

I have noticed however, that there are a few shapefiles that are unable to be read in, and thought best to raise this as a potential issue.

An exception is thrown when this line is executed in my project: foreach (var feature in Shapefile.ReadAllFeatures(filePath)) { ... }

The exception thrown: NetTopologySuite.IO.Esri.ShapefileException : {"Invalid polygon geometry.":null}

StackTrace: at NetTopologySuite.IO.Esri.Shp.Readers.ShpPolygonReader.BuildMultiPolygon(ShpMultiPartBuilder parts) at NetTopologySuite.IO.Esri.Shp.Readers.ShpPolygonReader.ReadGeometry(Stream stream, MultiPolygon& geometry) at NetTopologySuite.IO.Esri.Shp.Readers.ShpReader1.ReadCore(Int32& skippedCount) at NetTopologySuite.IO.Esri.Shapefiles.Readers.ShapefileReader1.Read(Boolean& deleted) at NetTopologySuite.IO.Esri.Shapefiles.Readers.ShapefileReader1.Read(Boolean& deleted, Feature& feature) at NetTopologySuite.IO.Esri.Shapefiles.Readers.ShapefileReader.FeatureEnumerator.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable1 source) at NetTopologySuite.IO.Esri.Shapefile.ReadAllFeatures(String shpPath, ShapefileReaderOptions options)

I've attached a couple of the shapefile examples, that cause the same exception to be thrown just below, Example Shapefiles.zip FYI: Shapefiles are from here: https://hub.arcgis.com/documents/NSTAUTHORITY::-nsta-offshore-zipped-shapefiles-wgs84/about

Thanks in advance for your help, Emma

[KubaSzostak]

You got an error because the shapefiles contain invalid geometries (confirmed by GDAL) and you are using default GeometryBuilderMode (Strict). You can ignore invalid geometries by explicitly setting ShapefileReaderOptions:

var opts = new ShapefileReaderOptions()
{
    GeometryBuilderMode = GeometryBuilderMode.IgnoreInvalidShapes
};
var features = Shapefile.ReadAllFeatures(shpPath, opts);

[KubaSzostak]

Thanks to your feedback a bug was found and fixed. Thank you @Em3a-c !

[Em3a-c]

Thanks alot for your help @KubaSzostak