// adds feature to node
public void add(Feature f)
{
// if node is leaf node and has less than 20 features
if (!hasChildren && features.Count < 20)
{
features.Add(f);
f.Parent = this;
return;
}
// if node is leaf node and has more than 19 children
if (!hasChildren)
split(); // split node and divide features
foreach (QuadTree qt in children)
{
// if child completely contains feature
if (qt.gboundary.Contains(f.Geometry))
{
qt.add(f);
return;
}
}
// if feature spans multiple children
features.Add(f);
f.Parent = this;
}
private void readShape()
{
// read shape id, data length and shape type
int id = br.ReadInt32BigEndian();
int length = br.ReadInt32BigEndian();
int stype = br.ReadInt32();
pos += 12;
if (stype == 0) // Null
return;
Geometry g = null;
if (stype == 1) // Point
g = readPoint();
if (stype == 3) // Polyline
g = readPolyline();
if (stype == 5) // Polygon
g = readPolygon();
// add shape to layer
if (g != null)
{
Feature f = new Feature(g, id);
layer.addFeature(f);
}
}
// returns attributes for feature in layer
public DataRow getRow(Feature f)
{
if (DataTable == null)
return null;
return DataTable.Rows[f.ID - 1];
}
// delete feature to layer
public void delFeature(Feature s)
{
if (s.Selected)
Selected.Remove(s);
if (s.Parent != null)
s.Parent.remove(s);
Features.Remove(s.ID);
}
// adds feature to layer
public int addFeature(Feature s)
{
// checks for correct shapetype
// a layer may only contain shapes of one type
if (shapetype == ShapeType.EMPTY)
{
shapetype = convert(s.Geometry.GeometryType);
if (shapetype == ShapeType.POINT) // default to black color for points
Style.brush = new System.Drawing.SolidBrush(System.Drawing.Color.Black);
}
else if (shapetype != convert(s.Geometry.GeometryType))
throw new Exception("Wrong shapetype in layer " + name);
// assigns id to feature
if (s.ID > maxid)
maxid = s.ID + 1;
if (s.ID == -1)
s.ID = maxid++;
Features.Add(s.ID, s);
if (QuadTree != null)
QuadTree.add(s);
return s.ID;
}
// perform union on currently selected layer
private void unionButton_Click(object sender, EventArgs e)
{
toolBuilder.addHeader("Union");
// textbox for new layername
TextBox textbox = toolBuilder.addTextboxWithCaption("New layername:");
Label errorLabel = toolBuilder.addErrorLabel();
Button button = toolBuilder.addButton("Union", (Layer l) =>
{
// user has not set new layername
if (textbox.Text.Length == 0)
{
toolBuilder.setError("Provide name");
return;
}
// create temporary layer
Layer copyLayer = new Layer(l.Name);
copyLayer.Boundingbox = new Envelope(l.Boundingbox);
copyLayer.createQuadTree();
// copy all features to temp layer
foreach (Feature f in l.Features.Values)
copyLayer.addFeature(new Feature((IGeometry)f.Geometry.Clone(), f.ID));
// create new layer with same boundingbox
Layer newLayer = new Layer(textbox.Text);
newLayer.Boundingbox = new Envelope(l.Boundingbox);
newLayer.createQuadTree();
// init progress bar
int numFeatures = copyLayer.Features.Values.Count;
progressLabel.Text = "Performing union";
progressBar.Minimum = 0;
progressBar.Maximum = numFeatures;
BackgroundWorker bw = new BackgroundWorker();
bw.WorkerReportsProgress = true;
// perform merge in another thread
bw.DoWork += (object wsender, DoWorkEventArgs we) =>
{
// threadsafe list of merged features
ConcurrentBag<Feature> newFeatures = new ConcurrentBag<Feature>();
var finished = new CountdownEvent(1);
Object _lock = new object();
// create thread function
var merge = new WaitCallback((state) =>
{
Random rnd = new Random();
while (true)
{
Feature f;
lock (_lock)
{
// break if no more features
if (copyLayer.Features.Count == 0)
break;
// get random index
int index = rnd.Next(copyLayer.Features.Count);
// get corresponding random feature
f = copyLayer.Features[copyLayer.Features.Keys.ToList()[index]];
// remove feature from layer
copyLayer.delFeature(f);
}
f.ID = -1;
while (true)
{
List<Feature> intersects;
// aquire lock to avoid race conditions
lock (_lock)
{
// get all features intersecting feature
intersects = copyLayer.getWithin(f.Geometry);
// remove features from layer
foreach (Feature intersect in intersects)
copyLayer.delFeature(intersect);
}
// if no intersects, no merging is necessary
if (intersects.Count == 0)
break;
// merge all features
foreach (Feature intersect in intersects)
{
f = new Feature(f.Geometry.Union(intersect.Geometry));
bw.ReportProgress(1);
}
}
// add feature to list of new features
newFeatures.Add(f);
}
finished.Signal();
});
// spawn eight threads, this is not always optimal but a good approximation
for (int i = 0; i < 8; i++)
{
finished.AddCount();
ThreadPool.QueueUserWorkItem(merge);
}
finished.Signal();
finished.Wait();
bw.ReportProgress(-newFeatures.Count);
// add all merged features back to temp layer
foreach (Feature f in newFeatures)
copyLayer.addFeature(f);
newFeatures = new ConcurrentBag<Feature>();
finished = new CountdownEvent(1);
// perform a final single threaded merge
merge(false);
// add all final merged features to new layer
foreach (Feature f in newFeatures)
newLayer.addFeature(f);
};
bw.RunWorkerCompleted += (object wsender, RunWorkerCompletedEventArgs we) =>
{
// reset progress bar
progressBar.Value = 0;
progressLabel.Text = "";
// insert new layer and redraw map
Layers.Insert(0, newLayer);
redraw();
};
bw.ProgressChanged += (object wsender, ProgressChangedEventArgs we) =>
{
// update progress bar
if (we.ProgressPercentage < 0)
{
progressBar.Value = 0;
progressBar.Maximum = -we.ProgressPercentage;
progressLabel.Text = "Union - Second pass";
}
else
progressBar.Value += we.ProgressPercentage;
};
bw.RunWorkerAsync();
});
// reset default new layer name when selected layer is changed
toolBuilder.resetAction = (Layer l) => {
textbox.Text = (l == null) ? "" : l.Name + "_union";
};
toolBuilder.reset();
}
// calculate intersection of layers
private void intersectButton_Click(object sender, EventArgs e)
{
toolBuilder.addHeader("Intersect");
// dropdown for selecting other layer
ComboBox layerSelect = toolBuilder.addLayerSelect("Intersect with:");
// textbox for new layer name
TextBox textbox = toolBuilder.addTextboxWithCaption("New layername:");
// laber for errors
Label errorLabel = toolBuilder.addErrorLabel();
//button for performing intersection
Button button = toolBuilder.addButton("Intersect", (Layer l) =>
{
// new layer name not given
if (textbox.Text.Length == 0)
{
toolBuilder.setError("Provide name");
return;
}
Layer intersectLayer = (Layer)layerSelect.SelectedItem;
Layer newLayer = new Layer(textbox.Text);
// if both layers have attributes
if (l.DataTable != null && intersectLayer.DataTable != null)
{
// merge attributes, columnName collisions may be overwritten
DataTable a = l.DataTable.Clone();
newLayer.DataTable = intersectLayer.DataTable.Clone();
newLayer.DataTable.Merge(a, true, MissingSchemaAction.Add);
}
// if only one layer has attributes
else if (l.DataTable != null && intersectLayer.DataTable == null)
{
newLayer.DataTable = l.DataTable.Clone();
}
// if only the other layer has attributes
else if (l.DataTable == null && intersectLayer.DataTable != null)
{
newLayer.DataTable = intersectLayer.DataTable.Clone();
}
// init progress bar
progressLabel.Text = "Intersection";
progressBar.Minimum = 0;
progressBar.Maximum = l.Features.Values.Count;
// background worker for running in another thread
BackgroundWorker bw = new BackgroundWorker();
bw.WorkerReportsProgress = true;
bw.DoWork += (object wsender, DoWorkEventArgs we) =>
{
// loop through all features
for (int i = 0; i < l.Features.Count; i++ )
{
Feature f = l.Features.Values.ElementAt(i);
bw.ReportProgress(i);
// get intersecting features
var intersections = intersectLayer.getWithin(f.Geometry);
foreach (Feature intersect in intersections)
{
DataRow arow = l.getRow(f);
DataRow brow = intersectLayer.getRow(intersect);
// calculate intersection
Feature result = new Feature(f.Geometry.Intersection(intersect.Geometry));
int id = newLayer.addFeature(result);
// merge attributes
if (newLayer.DataTable != null)
{
DataRow dr = newLayer.DataTable.NewRow();
if (arow != null)
foreach (DataColumn dc in arow.Table.Columns)
dr[dc.ColumnName] = arow[dc.ColumnName];
if (brow != null)
foreach (DataColumn dc in brow.Table.Columns)
dr[dc.ColumnName] = brow[dc.ColumnName];
dr["sgis_id"] = id;
newLayer.DataTable.Rows.Add(dr);
}
}
}
};
bw.RunWorkerCompleted += (object wsender, RunWorkerCompletedEventArgs we) =>
{
// reset progress bar
progressBar.Value = 0;
progressLabel.Text = "";
// finalise new layer
newLayer.calculateBoundingBox();
newLayer.createQuadTree();
Layers.Insert(0, newLayer);
redraw();
};
bw.ProgressChanged += (object wsender, ProgressChangedEventArgs we) =>
{
// update progress bar
progressBar.Value = we.ProgressPercentage;
};
bw.RunWorkerAsync();
});
// reset new layer name
toolBuilder.resetAction += (Layer l) =>
{
textbox.Text = (l == null) ? "" : l.Name + "_intersect";
};
toolBuilder.reset();
}
private void diffButton_Click(object sender, EventArgs e)
{
toolBuilder.addHeader("Difference");
// dropdown for selecting other layer
ComboBox layerSelect = toolBuilder.addLayerSelect("Layer to subtract:");
// textbox for new layer name
TextBox textbox = toolBuilder.addTextboxWithCaption("New layername:");
// label for errors
Label errorLabel = toolBuilder.addErrorLabel();
// button for performing subtraction
Button button = toolBuilder.addButton("Subtract", (Layer l) =>
{
// no new layer name is given
if (textbox.Text.Length == 0)
{
toolBuilder.setError("Provide name");
return;
}
// layers must have the same type of shapes
Layer unionLayer = (Layer)layerSelect.SelectedItem;
if (l.shapetype != unionLayer.shapetype)
{
toolBuilder.setError("Incompatible types");
return;
}
Layer newLayer = new Layer(textbox.Text);
newLayer.DataTable = l.DataTable;
// init progress bar
progressLabel.Text = "Subtracting";
progressBar.Minimum = 0;
progressBar.Maximum = l.Features.Values.Count;
// background worker for running operation in another thread
BackgroundWorker bw = new BackgroundWorker();
bw.WorkerReportsProgress = true;
bw.DoWork += (object wsender, DoWorkEventArgs we) =>
{
// threadsafe list for storing new features
ConcurrentBag<Feature> newFeatures = new ConcurrentBag<Feature>();
using (var finished = new CountdownEvent(1))
{
foreach (Feature f in l.Features.Values)
{
finished.AddCount();
Feature capt = f;
// in each thread
ThreadPool.QueueUserWorkItem((state) =>
{
// clone feature
Feature newf = new Feature((IGeometry)capt.Geometry.Clone(), capt.ID);
// get intersecting features
var intersects = unionLayer.getWithin(capt.Geometry);
// subtract intersecting features
foreach (Feature intersect in intersects)
newf.Geometry = newf.Geometry.Difference(intersect.Geometry);
// if there is something left of the original feature
if (!newf.Geometry.IsEmpty) // add it to new feature list
newFeatures.Add(newf);
bw.ReportProgress(1);
finished.Signal();
}, null);
}
finished.Signal();
finished.Wait();
}
bw.ReportProgress(-newFeatures.Count);
// add all processed features to new layer
foreach (Feature f in newFeatures)
{
newLayer.addFeature(f);
bw.ReportProgress(1);
}
};
bw.RunWorkerCompleted += (object wsender, RunWorkerCompletedEventArgs we) =>
{
// reset progressbar
progressBar.Value = 0;
progressLabel.Text = "";
// create quad tree and insert new layer
newLayer.calculateBoundingBox();
newLayer.createQuadTree();
Layers.Insert(0, newLayer);
redraw();
};
bw.ProgressChanged += (object wsender, ProgressChangedEventArgs we) =>
{
// update progress bar
if (we.ProgressPercentage < 0)
{
progressBar.Value = 0;
progressBar.Maximum = -we.ProgressPercentage;
progressLabel.Text = "Creating spatial index";
}
else
progressBar.Value += we.ProgressPercentage;
};
bw.RunWorkerAsync();
});
// reset new layer name when selected layer changes
toolBuilder.resetAction += (Layer l) =>
{
textbox.Text = (l == null) ? "" : l.Name + "_diff";
};
toolBuilder.reset();
}
public void remove(Feature f)
{
features.Remove(f);
}
