private void btnFindFeaturesInBuffer_Click(object sender, EventArgs e)
{
MgSelectionBase selection = _viewer.GetSelection();
MgReadOnlyLayerCollection selectedLayers = selection.GetLayers();
if (selectedLayers == null)
{
MessageBox.Show("Select a parcel");
return;
}
MgLayerBase parcels = null;
for (int i = 0; i < selectedLayers.GetCount(); i++)
{
MgLayerBase layer = selectedLayers.GetItem(i);
if (layer.Name == "Parcels")
{
parcels = layer;
break;
}
}
if (parcels == null)
{
MessageBox.Show("Select a parcel");
return;
}
int bufferRingSize = 500; // measured in metres
// Set up some objects for coordinate conversion
MgMapBase map = _viewer.GetMap();
MgLayerCollection mapLayers = map.GetLayers();
MgMapViewerProvider provider = _viewer.GetProvider();
MgResourceService resourceService = (MgResourceService)provider.CreateService(MgServiceType.ResourceService);
//Casting to MgdFeatureService because we want to use convenience APIs
MgFeatureService featureService = (MgdFeatureService)provider.CreateService(MgServiceType.FeatureService);
string sessionId = Guid.NewGuid().ToString();
String mapWktSrs = map.GetMapSRS();
MgAgfReaderWriter agfReaderWriter = new MgAgfReaderWriter();
MgWktReaderWriter wktReaderWriter = new MgWktReaderWriter();
MgCoordinateSystemFactory coordinateSystemFactory = new MgCoordinateSystemFactory();
MgCoordinateSystem srs = coordinateSystemFactory.Create(mapWktSrs);
MgMeasure srsMeasure = srs.GetMeasure();
// Check for a buffer layer. If it exists, delete
// the current features.
// If it does not exist, create a feature source and
// a layer to hold the buffer.
BufferHelper helper = new BufferHelper();
MgdLayer bufferLayer = null;
int layerIndex = map.GetLayers().IndexOf("Buffer");
if (layerIndex < 0)
{
// The layer does not exist and must be created.
MgResourceIdentifier bufferFeatureResId = new MgResourceIdentifier("Session:" + sessionId + "//Buffer.FeatureSource");
helper.CreateBufferFeatureSource(featureService, mapWktSrs, bufferFeatureResId);
bufferLayer = helper.CreateBufferLayer(resourceService, bufferFeatureResId, sessionId);
map.GetLayers().Insert(0, bufferLayer);
}
else
{
bufferLayer = (MgdLayer)map.GetLayers().GetItem(layerIndex);
bufferLayer.DeleteFeatures("ID like '%'");
}
// Check for a parcel marker layer. If it exists, delete
// the current features.
// If it does not exist, create a feature source and
// a layer to hold the parcel markers.
MgdLayer parcelMarkerLayer = null;
layerIndex = map.GetLayers().IndexOf("ParcelMarker");
if (layerIndex < 0)
{
MgResourceIdentifier parcelFeatureResId = new MgResourceIdentifier("Session:" + sessionId + "//ParcelMarker.FeatureSource");
helper.CreateParcelMarkerFeatureSource(featureService, mapWktSrs, parcelFeatureResId);
parcelMarkerLayer = helper.CreateParcelMarkerLayer(resourceService, parcelFeatureResId, sessionId);
map.GetLayers().Insert(0, parcelMarkerLayer);
}
else
{
parcelMarkerLayer = (MgdLayer)map.GetLayers().GetItem(layerIndex);
parcelMarkerLayer.DeleteFeatures("ID like '%'");
}
// Check each layer in the selection.
for (int i = 0; i < selectedLayers.GetCount(); i++)
{
// Only check selected features in the Parcels layer.
MgdLayer layer = (MgdLayer)selectedLayers.GetItem(i);
if (layer.GetName() == "Parcels")
{
string geomName = layer.GetFeatureGeometryName();
System.Diagnostics.Trace.TraceInformation("Marking all parcels inside the buffer that are of type 'MFG'");
MgFeatureReader featureReader = selection.GetSelectedFeatures(layer, layer.GetFeatureClassName(), false);
// Process each item in the MgFeatureReader. Get the
// geometries from all the selected features and
// merge them into a single geometry.
MgGeometryCollection inputGeometries = new MgGeometryCollection();
while (featureReader.ReadNext())
{
MgByteReader featureGeometryData = featureReader.GetGeometry(geomName);
MgGeometry featureGeometry = agfReaderWriter.Read(featureGeometryData);
inputGeometries.Add(featureGeometry);
}
MgGeometryFactory geometryFactory = new MgGeometryFactory();
MgGeometry mergedGeometries = geometryFactory.CreateMultiGeometry(inputGeometries);
// Create a buffer from the merged geometries
double bufferDist = srs.ConvertMetersToCoordinateSystemUnits(bufferRingSize);
MgGeometry bufferGeometry = mergedGeometries.Buffer(bufferDist, srsMeasure);
// Create a filter to select parcels within the buffer. Combine
// a basic filter and a spatial filter to select all parcels
// within the buffer that are of type "MFG".
MgFeatureQueryOptions queryOptions = new MgFeatureQueryOptions();
queryOptions.SetFilter("RTYPE = 'MFG'");
queryOptions.SetSpatialFilter(geomName, bufferGeometry, MgFeatureSpatialOperations.Inside);
featureReader = layer.SelectFeatures(queryOptions);
// Get the features from the feature source,
// determine the centroid of each selected feature, and
// add a point to the ParcelMarker layer to mark the
// centroid.
// Collect all the points into an MgFeatureCommandCollection,
// so they can all be added in one operation.
MgFeatureCommandCollection parcelMarkerCommands = new MgFeatureCommandCollection();
int inserted = 0;
while (featureReader.ReadNext())
{
MgByteReader byteReader = featureReader.GetGeometry(geomName);
MgGeometry geometry = agfReaderWriter.Read(byteReader);
MgPoint point = geometry.GetCentroid();
// Create an insert command for this parcel.
MgPropertyCollection properties = new MgPropertyCollection();
properties.Add(new MgGeometryProperty("ParcelLocation", agfReaderWriter.Write(point)));
//parcelMarkerCommands.Add(new MgInsertFeatures("ParcelMarkerClass", properties));
MgFeatureReader fr = parcelMarkerLayer.InsertFeatures(properties);
fr.Close();
inserted++;
}
featureReader.Close();
if (inserted == 0)
{
MessageBox.Show("No parcels within the buffer area match.");
return;
}
// Create a feature in the buffer feature source to show the area covered by the buffer.
MgPropertyCollection props = new MgPropertyCollection();
props.Add(new MgGeometryProperty("BufferGeometry", agfReaderWriter.Write(bufferGeometry)));
bufferLayer.InsertFeatures(props);
// Ensure that the buffer layer is visible and in the legend.
bufferLayer.SetVisible(true);
bufferLayer.ForceRefresh();
bufferLayer.SetDisplayInLegend(true);
parcelMarkerLayer.SetVisible(true);
parcelMarkerLayer.ForceRefresh();
MessageBox.Show("Done");
_viewer.RefreshMap();
IMapLegend legend = Shell.Instance.Legend;
if (legend != null)
{
legend.RefreshLegend();
}
}
}
}
