ProSnippets Raster

Language:              C#  
Subject:               Raster  
Contributor:           ArcGIS Pro SDK Team <arcgisprosdk@esri.com>  
Organization:          esri, http://www.esri.com  
Date:                  4/22/2024  
ArcGIS Pro:            3.3  
Visual Studio:         2022  
.NET Target Framework: .Net 6  

Open raster dataset in a folder

// Create a FileSystemConnectionPath using the folder path.
FileSystemConnectionPath connectionPath = new FileSystemConnectionPath(new System.Uri(@"C:\Temp"), FileSystemDatastoreType.Raster);
// Create a new FileSystemDatastore using the FileSystemConnectionPath.
FileSystemDatastore dataStore = new FileSystemDatastore(connectionPath);
// Open the raster dataset.
RasterDataset fileRasterDataset = dataStore.OpenDataset<RasterDataset>("Sample.tif");

Open raster dataset in a geodatabase

// Create a FileGeodatabaseConnectionPath using the path to the gdb. Note: This can be a path to a .sde file.
FileGeodatabaseConnectionPath geodatabaseConnectionPath = new FileGeodatabaseConnectionPath(new Uri(@"C:\Temp\rasters.gdb"));
// Create a new Geodatabase object using the FileGeodatabaseConnectionPath.
Geodatabase geodatabase = new Geodatabase(geodatabaseConnectionPath);
// Open the raster dataset.
RasterDataset gdbRasterDataset = geodatabase.OpenDataset<RasterDataset>("sample");

Get the raster dataset definition from a raster dataset

await QueuedTask.Run(() =>
{
  RasterDatasetDefinition rasterDatasetDefinition = rasterDataset.GetDefinition();

  // access the dataset definition properties
  rasterDatasetDefinition.GetBandCount();
});

Access the bands in a raster dataset

var count = rasterDataset.GetBandCount();
RasterBand rasterBandByName = rasterDataset.GetBandByName(sBandName);
var index = rasterDataset.GetBandIndex(sBandName);

// Get a RasterBand from the raster dataset
RasterBand rasterBand = rasterDataset.GetBand(0);

// Get the RasterBandDefinition from the raster band.
RasterBandDefinition rasterBandDefinition = rasterBand.GetDefinition();
// Get the name of the raster band from the raster band.
string bandName = rasterBandDefinition.GetName();

Access rows in a raster attribute table

var raster = MapView.Active.Map.GetLayersAsFlattenedList().OfType<RasterLayer>().FirstOrDefault();
if (raster != null)
{
  await QueuedTask.Run(() =>
  {
    var rasterTbl = raster.GetRaster().GetAttributeTable();
    var cursor = rasterTbl.Search();
    while (cursor.MoveNext())
    {
      var row = cursor.Current;
    }
  });
}

Create a raster cursor to iterate through the raster data

await QueuedTask.Run(() =>
{
  // Create a full raster from the raster dataset.
  ArcGIS.Core.Data.Raster.Raster raster = rasterDataset.CreateFullRaster();

  // Calculate size of pixel blocks to process. Use 1000 or height/width of the raster, whichever is smaller.
  var height = raster.GetHeight();
  var width = raster.GetWidth();
  int pixelBlockHeight = height > 1000 ? 1000 : height;
  int pixelBlockWidth = width > 1000 ? 1000 : width;

  // Create the raster cursor using the height and width calculated.
  RasterCursor rasterCursor = raster.CreateCursor(pixelBlockWidth, pixelBlockHeight);

  // Use a do-while loop to iterate through the pixel blocks of the raster using the raster cursor.
  do
  {
    // Get the current pixel block from the cursor.
    using (PixelBlock currentPixelBlock = rasterCursor.Current)
    {
      // Do something with the pixel block...
    }

    // Once you are done, move to the next pixel block.
  }
  while (rasterCursor.MoveNext());
});

Read and Write pixels from and to a raster dataset using pixel blocks

await QueuedTask.Run(() =>
{
  // Create a full raster from the raster dataset.
  ArcGIS.Core.Data.Raster.Raster raster = rasterDataset.CreateFullRaster();

  // Calculate size of pixel block to create. Use 128 or height/width of the raster, whichever is smaller.
  var height = raster.GetHeight();
  var width = raster.GetWidth();
  int pixelBlockHeight = height > 128 ? 128 : height;
  int pixelBlockWidth = width > 128 ? 128 : width;

  // Create a new (blank) pixel block.
  PixelBlock currentPixelBlock = raster.CreatePixelBlock(pixelBlockWidth, pixelBlockHeight);

  // Read pixel values from the raster dataset into the pixel block starting from the given top left corner.
  raster.Read(0, 0, currentPixelBlock);

  // Do something with the pixel block...

  // Write the pixel block to the raster dataset starting from the given top left corner.
  raster.Write(0, 0, currentPixelBlock);
});

Process pixels using a pixel block

await QueuedTask.Run(() =>
{
  // Read pixel values from the raster dataset into the pixel block starting from the given top left corner.
  raster.Read(0, 0, currentPixelBlock);

  // For each plane (band) in the pixel block
  for (int plane = 0; plane < currentPixelBlock.GetPlaneCount(); plane++)
  {
    // Get a copy of the array of pixels from the pixel block corresponding to the current plane.
    Array sourcePixels = currentPixelBlock.GetPixelData(plane, true);
    // Get the height and width of the pixel block.
    int pBHeight = currentPixelBlock.GetHeight();
    int pBWidth = currentPixelBlock.GetWidth();

    // Iterate through the pixels in the array.
    for (int i = 0; i < pBHeight; i++)
    {
      for (int j = 0; j < pBWidth; j++)
      {
        // Get the NoData mask value to see if the pixel is a valid pixel.
        if (Convert.ToByte(currentPixelBlock.GetNoDataMaskValue(plane, j, i)) == 1)
        {
          // Get the pixel value from the array and process it (add 5 to the value).
          // Note: This is assuming the pixel type is Unisigned 8bit.
          int pixelValue = Convert.ToInt16(sourcePixels.GetValue(j, i)) + 5;
          // Make sure the pixel value does not go above the range of the pixel type.
          pixelValue = pixelValue > 254 ? 254 : pixelValue;
          // Set the new pixel value to the array.
          // Note: This is assuming the pixel type is Unisigned 8bit.
          sourcePixels.SetValue(Convert.ToByte(pixelValue), j, i);
        }
      }
    }
    // Set the modified array of pixels back to the pixel block.
    currentPixelBlock.SetPixelData(plane, sourcePixels);
  }
  // Write the pixel block to the raster dataset starting from the given top left corner.
  raster.Write(0, 0, currentPixelBlock);
});

Calculate Raster statistics

//If a raster dataset has statistics, you can create a raster layer and get these statistics by accessing the colorizer.
await QueuedTask.Run(() =>
{
  //Accessing the raster layer
  var lyr = MapView.Active.Map.GetLayersAsFlattenedList().OfType<BasicRasterLayer>().FirstOrDefault();
  //Getting the colorizer
  var colorizer = lyr.GetColorizer() as CIMRasterStretchColorizer;
  //Accessing the statistics
  var stats = colorizer.StretchStats;
  var max = stats.max;
  var min = stats.min;
});