光栅

在文件夹中打开栅格数据集

1
2
3
4
5
6
// 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");

在地理数据库中打开栅格数据集

1
2
3
4
5
6
// 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");

从栅格数据集获取栅格数据集定义

1
2
3
4
5
6
7
await QueuedTask.Run(() =>
{
RasterDatasetDefinition rasterDatasetDefinition = rasterDataset.GetDefinition();

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

访问栅格数据集中的波段

1
2
3
4
5
6
7
8
9
10
11
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();

访问栅格属性表中的行

1
2
3
4
5
6
7
8
9
10
11
12
13
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;
}
});
}

创建栅格光标以循环访问栅格数据

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
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());
});

使用像素块在栅格数据集中读取和写入像素

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
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);
});

使用像素块处理像素

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
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);
});

计算栅格统计数据

1
2
3
4
5
6
7
8
9
10
11
12
//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;
});

;