GDALDatasetRasterIO.cs

Revision 14028, 10.5 kB (checked in by tamas, 8 months ago)
Added a C# sample to demonstrate the GDALDatasetRasterIO operations.

Line
1	/******************************************************************************
2	* $Id: GDALReadDirect.cs 13437 2007-12-21 21:02:38Z tamas $
3	*
4	* Name: GDALDatasetRasterIO.cs
5	* Project: GDAL CSharp Interface
6	* Purpose: A sample app to read GDAL raster data directly to a C# bitmap.
7	* Author: Tamas Szekeres, szekerest@gmail.com
8	*
9	******************************************************************************
10	* Copyright (c) 2007, Tamas Szekeres
11	*
12	* Permission is hereby granted, free of charge, to any person obtaining a
13	* copy of this software and associated documentation files (the "Software"),
14	* to deal in the Software without restriction, including without limitation
15	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
16	* and/or sell copies of the Software, and to permit persons to whom the
17	* Software is furnished to do so, subject to the following conditions:
18	*
19	* The above copyright notice and this permission notice shall be included
20	* in all copies or substantial portions of the Software.
21	*
22	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
23	* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
25	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28	* DEALINGS IN THE SOFTWARE.
29	*****************************************************************************/
30
31	using System;
32	using System.Drawing;
33	using System.Drawing.Imaging;
34
35	using OSGeo.GDAL;
36
37
38	/**
39
40	* <p>Title: GDAL C# GDALDatasetRasterIO example.</p>
41	* <p>Description: A sample app to read GDAL raster data directly to a C# bitmap.</p>
42	* @author Tamas Szekeres (szekerest@gmail.com)
43	* @version 1.0
44	*/
45
46
47
48	/// <summary>
49	/// A C# based sample to read GDAL raster data directly to a C# bitmap.
50	/// </summary>
51
52	class GDALReadDirect {
53
54	public static void usage()
55
56	{
57	Console.WriteLine("usage: GDALDatasetRasterIO {GDAL dataset name} {output file name}");
58	System.Environment.Exit(-1);
59	}
60
61	public static void Main(string[] args)
62	{
63	if (args.Length < 2) usage();
64
65	// Using early initialization of System.Console
66	Console.WriteLine("");
67
68	try
69	{
70	/* -------------------------------------------------------------------- */
71	/* Register driver(s). */
72	/* -------------------------------------------------------------------- */
73	Gdal.AllRegister();
74
75	/* -------------------------------------------------------------------- */
76	/* Open dataset. */
77	/* -------------------------------------------------------------------- */
78	Dataset ds = Gdal.Open( args[0], Access.GA_ReadOnly );
79
80	if (ds == null)
81	{
82	Console.WriteLine("Can't open " + args[0]);
83	System.Environment.Exit(-1);
84	}
85
86	Console.WriteLine("Raster dataset parameters:");
87	Console.WriteLine(" Projection: " + ds.GetProjectionRef());
88	Console.WriteLine(" RasterCount: " + ds.RasterCount);
89	Console.WriteLine(" RasterSize (" + ds.RasterXSize + "," + ds.RasterYSize + ")");
90
91	/* -------------------------------------------------------------------- */
92	/* Get driver */
93	/* -------------------------------------------------------------------- */
94	Driver drv = ds.GetDriver();
95
96	if (drv == null)
97	{
98	Console.WriteLine("Can't get driver.");
99	System.Environment.Exit(-1);
100	}
101
102	Console.WriteLine("Using driver " + drv.LongName);
103
104	/* -------------------------------------------------------------------- */
105	/* Processing the raster */
106	/* -------------------------------------------------------------------- */
107	SaveBitmapDirect(args[1], ds, 0, 0, ds.RasterXSize, ds.RasterYSize, ds.RasterXSize, ds.RasterYSize);
108
109	}
110	catch (Exception e)
111	{
112	Console.WriteLine("Application error: " + e.Message);
113	}
114	}
115
116	private static void SaveBitmapDirect(string filename, Dataset ds, int xOff, int yOff, int width, int height, int imageWidth, int imageHeight)
117	{
118	if (ds.RasterCount == 0)
119	return;
120
121	int[] bandMap = new int[4] { 1, 1, 1, 1 };
122	int channelCount = 1;
123	bool hasAlpha = false;
124	bool isIndexed = false;
125	int channelSize = 8;
126	ColorTable ct = null;
127	// Evaluate the bands and find out a proper image transfer format
128	for (int i = 0; i < ds.RasterCount; i++)
129	{
130	Band band = ds.GetRasterBand(i + 1);
131	if (Gdal.GetDataTypeSize(band.DataType) > 8)
132	channelSize = 16;
133	switch (band.GetRasterColorInterpretation())
134	{
135	case ColorInterp.GCI_AlphaBand:
136	channelCount = 4;
137	hasAlpha = true;
138	bandMap[3] = i + 1;
139	break;
140	case ColorInterp.GCI_BlueBand:
141	if (channelCount < 3)
142	channelCount = 3;
143	bandMap[0] = i + 1;
144	break;
145	case ColorInterp.GCI_RedBand:
146	if (channelCount < 3)
147	channelCount = 3;
148	bandMap[2] = i + 1;
149	break;
150	case ColorInterp.GCI_GreenBand:
151	if (channelCount < 3)
152	channelCount = 3;
153	bandMap[1] = i + 1;
154	break;
155	case ColorInterp.GCI_PaletteIndex:
156	ct = band.GetRasterColorTable();
157	isIndexed = true;
158	bandMap[0] = i + 1;
159	break;
160	case ColorInterp.GCI_GrayIndex:
161	isIndexed = true;
162	bandMap[0] = i + 1;
163	break;
164	default:
165	// we create the bandmap using the dataset ordering by default
166	if (i < 4 && bandMap[i] == 0)
167	{
168	if (channelCount < i)
169	channelCount = i;
170	bandMap[i] = i + 1;
171	}
172	break;
173	}
174	}
175
176	// find out the pixel format based on the gathered information
177	PixelFormat pixelFormat;
178	DataType dataType;
179	int pixelSpace;
180
181	if (isIndexed)
182	{
183	pixelFormat = PixelFormat.Format8bppIndexed;
184	dataType = DataType.GDT_Byte;
185	pixelSpace = 1;
186	}
187	else
188	{
189	if (channelCount == 1)
190	{
191	if (channelSize > 8)
192	{
193	pixelFormat = PixelFormat.Format16bppGrayScale;
194	dataType = DataType.GDT_Int16;
195	pixelSpace = 2;
196	}
197	else
198	{
199	pixelFormat = PixelFormat.Format24bppRgb;
200	channelCount = 3;
201	dataType = DataType.GDT_Byte;
202	pixelSpace = 3;
203	}
204	}
205	else
206	{
207	if (hasAlpha)
208	{
209	if (channelSize > 8)
210	{
211	pixelFormat = PixelFormat.Format64bppArgb;
212	dataType = DataType.GDT_UInt16;
213	pixelSpace = 8;
214	}
215	else
216	{
217	pixelFormat = PixelFormat.Format32bppArgb;
218	dataType = DataType.GDT_Byte;
219	pixelSpace = 4;
220	}
221	channelCount = 4;
222	}
223	else
224	{
225	if (channelSize > 8)
226	{
227	pixelFormat = PixelFormat.Format48bppRgb;
228	dataType = DataType.GDT_UInt16;
229	pixelSpace = 6;
230	}
231	else
232	{
233	pixelFormat = PixelFormat.Format24bppRgb;
234	dataType = DataType.GDT_Byte;
235	pixelSpace = 3;
236	}
237	channelCount = 3;
238	}
239	}
240	}
241
242
243	// Create a Bitmap to store the GDAL image in
244	Bitmap bitmap = new Bitmap(imageWidth, imageHeight, pixelFormat);
245
246	if (isIndexed)
247	{
248	// setting up the color table
249	if (ct != null)
250	{
251	int iCol = ct.GetCount();
252	ColorPalette pal = bitmap.Palette;
253	for (int i = 0; i < iCol; i++)
254	{
255	ColorEntry ce = ct.GetColorEntry(i);
256	pal.Entries[i] = Color.FromArgb(ce.c4, ce.c1, ce.c2, ce.c3);
257	}
258	bitmap.Palette = pal;
259	}
260	else
261	{
262	// grayscale
263	ColorPalette pal = bitmap.Palette;
264	for (int i = 0; i < 256; i++)
265	pal.Entries[i] = Color.FromArgb(255, i, i, i);
266	bitmap.Palette = pal;
267	}
268	}
269
270	// Use GDAL raster reading methods to read the image data directly into the Bitmap
271	BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, imageWidth, imageHeight), ImageLockMode.ReadWrite, pixelFormat);
272
273	try
274	{
275	int stride = bitmapData.Stride;
276	IntPtr buf = bitmapData.Scan0;
277
278	ds.ReadRaster(xOff, yOff, width, height, buf, imageWidth, imageHeight, dataType,
279	channelCount, bandMap, pixelSpace, stride, 1);
280	}
281	finally
282	{
283	bitmap.UnlockBits(bitmapData);
284	}
285
286	bitmap.Save(filename);
287	}
288	}

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