GIS_gdal geotiff文件与JAVA 浮点二维数组array之间的转换

谁践踏了优雅 2022-12-31 11:20 78阅读 0赞

# 说明： #

功能如题所示。

## geotiff文件 -> JAVA 浮点二维数组float\[\]\[\] : ##

*  输入： geotiff文件路径，
 *  输出： geotiff

import org.gdal.gdal.Dataset;
        import org.gdal.gdal.Driver;
        import org.gdal.gdal.gdal;
        import org.gdal.gdal.Band;
        import org.gdal.gdalconst.gdalconst;
        import org.gdal.gdalconst.gdalconstConstants;
    
        import java.io.File;
    
        public static float[][] GetRasterValuesFromFilePath(String tiffFilePath)
    	{
    		System.out.println("Info: Get Raster Values From File Path: " + tiffFilePath + "...");
    		
    		gdal.AllRegister();
    
    		Dataset ds = gdal.Open(tiffFilePath, gdalconstConstants.GA_ReadOnly);
    		if (ds == null)
    		{
    			System.err.println("ERR: GDALOpen failed - " + gdal.GetLastErrorNo());
    			System.err.println(gdal.GetLastErrorMsg());
    			System.exit(1);
    		}
    
    		Band band = ds.GetRasterBand(1);
    		
    		Driver hDriver = ds.GetDriver();
    		//System.out.println("Driver: " + hDriver.getShortName() + "/" + hDriver.getLongName());
    		int width = ds.getRasterXSize();
    		int height = ds.getRasterYSize();
    		//System.out.println("Size is " + width + ", " + height);
    		
    		float[][] resultArray = new float[height][width]; //注意这里高和宽别写反了
            float[] buffer = new float[width * height];
    
            band.ReadRaster(0, 0, width, height,gdalconst.GDT_Float32, buffer);
            for (int i = 0; i < buffer.length; i++)
    //          resultArray.SetValue(buffer[i], i / width, i % width);
            	resultArray[i/width][i%width] = buffer[i];
    
    		ds.delete();
    		gdal.GDALDestroyDriverManager();
    		
    		return resultArray;
    	}

## JAVA 浮点二维数组float\[\]\[\] -> geotiff文件: ##

*  输入： float\[\]\[\]数组 ，待输出的geotiff文件路径，以及geotiff必要的参数，
 *  输出 ：geotiff文件到指定上述路径

写geotfff文件，需要一些必要的参数，先定义一个类管理它，然后，再依靠已有的tiff文件（姑且称之为模板tiff文件吧）中获取的这些属性，进行写tiff文件。

写geotiff文件必要的参数类：

public class GeotiffParameters
    {
    	// ATTENTION: Assume all geotiff files share the same parameters as blow.
        double[] transform= new double[6];
        String projection;
        String rasterFormat;
        int xSize;
        int ySize;
        int bandCount;
        int dataType; 						//from the members of class gdalconst 
        Double[] noValue = new Double[1]; 	// ATTENTION: Assume all geotiff files only have one band.
    }

根据模板tiff获取上述参数：

public static GeotiffParameters GetGeotiffParameters(String tiffFilePath)
    	{
    		GeotiffParameters geotiffParameters = new GeotiffParameters();
    		
    		gdal.AllRegister();
    		Dataset ds = gdal.Open(tiffFilePath, gdalconstConstants.GA_ReadOnly);
    		if (ds == null)
    		{
    			System.err.println("ERR: GDALOpen failed - " + gdal.GetLastErrorNo());
    			System.err.println(gdal.GetLastErrorMsg());
    			System.exit(1);
    		}
    		
    		geotiffParameters.projection = ds.GetProjection();
    		ds.GetGeoTransform(geotiffParameters.transform);
    		
    		Driver hDriver = ds.GetDriver();
    		//System.out.println("Driver: " + hDriver.getShortName() + "/" + hDriver.getLongName());
    		
    		geotiffParameters.rasterFormat = hDriver.getShortName();
            // columns(xSize) and rows(ySize) of rasters
    		geotiffParameters.xSize     = ds.getRasterXSize();
    		geotiffParameters.ySize     = ds.getRasterYSize();  
    		geotiffParameters.bandCount = ds.getRasterCount();
    		geotiffParameters.dataType = ds.GetRasterBand(1).getDataType();
    		ds.GetRasterBand(1).GetNoDataValue(geotiffParameters.noValue);
    		//System.out.println(geotiffParameters.noValue[0]);//-3.4028234663852886E38
    
    		
    		return geotiffParameters;
    	}

根据上述写geotiff必要的参数，开始写geotiff文件吧：

public static Boolean CreateRasterToFilePath(String geotiffOutputFilePath, float[][] resultArray)
    	{
    		System.out.println("Info: Create Raster Data(.tif file) To File Path: " + geotiffOutputFilePath + "...");
    		
    		// if file exists, delete it.
    		File file = new File(geotiffOutputFilePath);
    		if(file.exists())
    		{
    			file.delete();
    		}
    		
    		int countColumn = mGeotiffParameters.xSize;  //322		
    		int countRow = mGeotiffParameters.ySize;     //562
    		int bandCount = mGeotiffParameters.bandCount;
    		int dataType = mGeotiffParameters.dataType;
    		String rasterFormat = mGeotiffParameters.rasterFormat;
    		
    		gdal.AllRegister();
    		
    		Driver driver = gdal.GetDriverByName(rasterFormat);
    		Dataset result = driver.Create(geotiffOutputFilePath, countColumn, countRow, bandCount, dataType);
    		
    		//set attributes
    		result.SetGeoTransform(mGeotiffParameters.transform);
    		result.SetProjection(mGeotiffParameters.projection);
    		
            float[] tmpData = new float[countColumn * countRow];
            float tmp;
            for (int i = 0; i < countRow; ++i)
            {
                for (int j = 0; j < countColumn; ++j)
                {
                    tmp = resultArray[i][j];
                    tmpData[i * countColumn + j] = tmp;
                }
            }
            result.GetRasterBand(1).SetNoDataValue(mGeotiffParameters.noValue[0]);
            // The value of xoff and yoff indicates the location that the upper left corner of the pixel block is to write.
            int check = result.GetRasterBand(1).WriteRaster(0, 0, countColumn, countRow, dataType, tmpData);
    
            if (check == gdalconst.CE_Failure)
                assert false:"write tmp geotiff failed!";
            else
            	return true;
            
            return false;
    	}