Michele,
I did a quick review of the code and changed the few places that were needed to make it work for ECW. Hope this saves you a few minutes. The changes are posted below. Please feel free to review the original code, or checkout all the cool code community project, and ask any question if you need clarification.
David
using System;
using System.Collections;
using System.Collections.ObjectModel;
using System.IO;
using GisSharpBlog.NetTopologySuite.Geometries;
using GisSharpBlog.NetTopologySuite.Index.Strtree;
using ThinkGeo.MapSuite.Core;
namespace MultiGeoRasterLayer
{
// IMPORTANT: You have to reference NetTopologySuite.dll & GeoApi.dll in your project. They come with Map Suite.
// This class speeds up the loading of a large number of Raster layers by loading and drawing on demand only the files
// in the current extent. Normally if you had 100 Raster files you would need to load 100 layers; however, this has performance
// issues--so we created this high level layer. It loads a reference file that contains the bounding box, path and file information for
// all of the Raster files. We load this information into an in-memory spatial index. When the map requests to draw the layer, we find the
// Rasters that are in the current extent, create a layer on-the-fly, call their Draw method and then close them. In this way, we load
// on demand only the files that are in the current extent.
// I have also included a small routine to build a reference file from a directory of Raster files.
// Reference File Format: [UpperLeftPointX],[LowerRightPoint.X],[UpperLeftPoint.Y],[LowerRightPoint.Y],[Path & File Name to Raster]
// Sample:
// -180.02197265625,-157.52197265625,-67.47802734375,-89.97802734375,..\..\App_Data\RasterImage\1.jpg
// -112.52197265625,-90.02197265625,-67.47802734375,-89.97802734375,..\..\App_Data\RasterImage\10.jpg
// 67.47802734375,89.97802734375,67.52197265625,45.02197265625,..\..\App_Data\RasterImage\100.jpg
// 89.97802734375,112.47802734375,67.52197265625,45.02197265625,..\..\App_Data\RasterImage\101.jpg
public class MultiGeoRasterLayer : Layer
{
private string rasterRefrencePathFileName;
private STRtree spatialIndex;
private double upperScale;
private double lowerScale;
private RectangleShape boundingBox;
private const int upperLeftXPosition = 0;
private const int upperLeftYPosition = 2;
private const int lowerRightXPosition = 1;
private const int lowerRightYPosition = 3;
private const int pathFileNamePosition = 4;
public MultiGeoRasterLayer()
: this(string.Empty, double.MaxValue, double.MinValue)
{ }
public MultiGeoRasterLayer(string rasterRefrencePathFileName)
: this(rasterRefrencePathFileName, double.MaxValue, double.MinValue)
{ }
public MultiGeoRasterLayer(string rasterRefrencePathFileName, double upperScale, double lowerScale)
{
this.rasterRefrencePathFileName = rasterRefrencePathFileName;
this.upperScale = upperScale;
this.lowerScale = lowerScale;
boundingBox = new RectangleShape();
}
public string RasterRefrencePathFileName
{
get { return rasterRefrencePathFileName; }
set { rasterRefrencePathFileName = value; }
}
public double UpperScale
{
get { return upperScale; }
set { upperScale = value; }
}
public double LowerScale
{
get { return lowerScale; }
set { lowerScale = value; }
}
// Here on the OpenCore we load our reference file and build the spatial index, which will be used in the DrawCore later.
// You need to make sure the reference file is in the right format as described in the comments above.
protected override void OpenCore()
{
if (File.Exists(rasterRefrencePathFileName))
{
string[] rasterFiles = File.ReadAllLines(rasterRefrencePathFileName);
spatialIndex = new STRtree(rasterFiles.Length);
Collection<BaseShape> boundingBoxes = new Collection<BaseShape>();
foreach (string rasterLine in rasterFiles)
{
string[] parts = rasterLine.Split(new string[] { "," }, StringSplitOptions.None);
RectangleShape rasterBoundingBox = new RectangleShape(new PointShape(double.Parse(parts[upperLeftXPosition]), double.Parse(parts[upperLeftYPosition])), new PointShape(double.Parse(parts[lowerRightXPosition]), double.Parse(parts[lowerRightYPosition])));
Envelope envelope = new Envelope(double.Parse(parts[upperLeftXPosition]), double.Parse(parts[lowerRightXPosition]), double.Parse(parts[upperLeftYPosition]), double.Parse(parts[lowerRightYPosition]));
spatialIndex.Insert(envelope, parts[pathFileNamePosition]);
}
spatialIndex.Build();
boundingBox = ExtentHelper.GetBoundingBoxOfItems(boundingBoxes);
}
else
{
throw new FileNotFoundException("The Raster reference file could not be found.", rasterRefrencePathFileName);
}
}
// Here we set the spatial index to null to clean up the memory and get ready for serialization
protected override void CloseCore()
{
spatialIndex = null;
}
// When we get to the Draw, things are easy. First we check to make sure we are within our scales.
// Next we look up the Raster files in the spatial index,
// then open their layer, call their Draw and close them.
protected override void DrawCore(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers)
{
double currentScale = ExtentHelper.GetScale(canvas.CurrentWorldExtent, canvas.Width, canvas.MapUnit);
if (currentScale >= lowerScale && currentScale <= upperScale)
{
RectangleShape currentExtent = canvas.CurrentWorldExtent;
Envelope currentExtentEnvelope = new Envelope(currentExtent.UpperLeftPoint.X, currentExtent.LowerRightPoint.X, currentExtent.UpperLeftPoint.Y, currentExtent.LowerRightPoint.Y);
ArrayList rasters = (ArrayList)spatialIndex.Query(currentExtentEnvelope);
foreach (string file in rasters)
{
EcwRasterLayer rasterRasterLayer = new EcwRasterLayer(file);
rasterRasterLayer.Open();
rasterRasterLayer.Draw(canvas, labelsInAllLayers);
rasterRasterLayer.Close();
}
}
}
// Here we let everyone know we support having a bounding box
public override bool HasBoundingBox
{
get
{
return true;
}
}
// We use the cached bounding box we set in the OpenCore
protected override RectangleShape GetBoundingBoxCore()
{
return boundingBox;
}
// This is just a handy function to build a reference file from a directory.
// You can tailor this code to fit your needs.
public static void BuildReferenceFile(string newReferencepathFileName, string pathOfRasterFiles)
{
if (Directory.Exists(pathOfRasterFiles))
{
string[] files = Directory.GetFiles(pathOfRasterFiles, "*.ecw");
StreamWriter streamWriter = null;
try
{
streamWriter = File.CreateText(newReferencepathFileName);
foreach (string file in files)
{
EcwRasterLayer rasterRasterLayer = new EcwRasterLayer(file);
rasterRasterLayer.Open();
RectangleShape boundingBox = rasterRasterLayer.GetBoundingBox();
rasterRasterLayer.Close();
streamWriter.WriteLine(string.Format("{0},{1},{2},{3},{4}", boundingBox.UpperLeftPoint.X, boundingBox.LowerRightPoint.X, boundingBox.UpperLeftPoint.Y, boundingBox.LowerRightPoint.Y, file));
}
streamWriter.Close();
}
finally
{
if (streamWriter != null) { streamWriter.Dispose(); }
}
}
else
{
throw new DirectoryNotFoundException("The path containing the Raster files could not be found.");
}
}
}
}
