public IFeatureSet BufferByDistance(double distance, int nSegments, bool selectedOnly, bool mergeResults)
{
var sf = _shapefile.BufferByDistance(distance, nSegments, selectedOnly, mergeResults);
return(WrapShapefile(sf));
}
// <summary>
// Creates several buffers around the waterways.
// </summary>
public void CreateBuffer(AxMap axMap1, string dataPath, System.Windows.Forms.ToolStripStatusLabel label)
{
axMap1.Projection = tkMapProjection.PROJECTION_GOOGLE_MERCATOR;
string filename = dataPath + "waterways.shp";
if (!File.Exists(filename))
{
MessageBox.Show("The shapefile with rivers wasn't found: " + filename);
}
else
{
var callback = new Callback(label);
var sf = new Shapefile();
if (!sf.Open(filename, callback))
{
MessageBox.Show(sf.ErrorMsg[sf.LastErrorCode]);
}
else
{
int layerHandle = axMap1.AddLayer(sf, true);
sf = axMap1.get_Shapefile(layerHandle); // in case a copy of shapefile was created by GlobalSettings.ReprojectLayersOnAdding
var utils = new Utils();
sf.DefaultDrawingOptions.LineWidth = 3.0f;
sf.DefaultDrawingOptions.LineColor = utils.ColorByName(tkMapColor.Blue);
const double distance = 150; // meters
var buffers = new List <Shapefile>();
for (int i = 1; i < 5; i++)
{
Shapefile sfBuffer = sf.BufferByDistance(distance * i, 30, false, true);
if (sfBuffer == null)
{
MessageBox.Show("Failed to calculate the buffer: " + sf.ErrorMsg[sf.LastErrorCode]);
return;
}
else
{
sfBuffer.GlobalCallback = callback;
buffers.Add(sfBuffer);
}
}
// now subtract smaller buffers from larger ones
for (int i = buffers.Count - 1; i > 0; i--)
{
Shapefile sfDiff = buffers[i].Difference(false, buffers[i - 1], false);
if (sfDiff == null)
{
MessageBox.Show("Failed to calculate the difference: " + sf.ErrorMsg[sf.LastErrorCode]);
return;
}
else
{
buffers[i] = sfDiff;
}
}
// pass all the resulting shapes to a single shapefile and mark their distance
Shapefile sfResult = buffers[0].Clone();
sfResult.GlobalCallback = callback;
int fieldIndex = sfResult.EditAddField("Distance", FieldType.DOUBLE_FIELD, 10, 12);
for (int i = 0; i < buffers.Count; i++)
{
Shapefile sfBuffer = buffers[i];
for (int j = 0; j < sfBuffer.NumShapes; j++)
{
int index = sfResult.NumShapes;
sfResult.EditInsertShape(sfBuffer.Shape[j].Clone(), ref index);
sfResult.EditCellValue(fieldIndex, index, distance * (i + 1));
}
}
// create visualization categories
sfResult.DefaultDrawingOptions.FillType = tkFillType.ftStandard;
sfResult.Categories.Generate(fieldIndex, tkClassificationType.ctUniqueValues, 0);
sfResult.Categories.ApplyExpressions();
// apply color scheme
var scheme = new ColorScheme();
scheme.SetColors2(tkMapColor.LightBlue, tkMapColor.LightYellow);
sfResult.Categories.ApplyColorScheme(tkColorSchemeType.ctSchemeGraduated, scheme);
layerHandle = axMap1.AddLayer(sfResult, true);
axMap1.Redraw();
//sfResult.SaveAs(@"c:\buffers.shp", null);
}
}
}