GDAL给定一套格网重投影坐标，分块进行影像投影转换c++

要使用GDAL进行分块的影像投影转换，可以进行以下步骤：

1. 打开原始影像和目标影像的数据集，例如：

#include "gdal_priv.h"
#include "cpl_conv.h" // for CPLMalloc()

GDALDataset *src_ds = (GDALDataset *) GDALOpen("input.tif", GA_ReadOnly);
GDALDataset *dst_ds = (GDALDataset *) GDALOpen("output.tif", GA_Update);

2. 获取原始影像和目标影像的投影信息和地理转换信息，例如：

const char *src_proj = src_ds->GetProjectionRef();
const char *dst_proj = dst_ds->GetProjectionRef();

double src_geotransform[6];
src_ds->GetGeoTransform(src_geotransform);

double dst_geotransform[6];
dst_ds->GetGeoTransform(dst_geotransform);

3. 创建一个投影转换器，并设置投影转换的参数，例如：

OSRCoordinateTransformation *transform =
    OGRCreateCoordinateTransformation(src_ds->GetSpatialRef(),
                                      dst_ds->GetSpatialRef());

4. 读取原始影像的像素数据，并进行投影转换，例如：

int block_size = 256;
int x_blocks = (src_ds->GetRasterXSize() + block_size - 1) / block_size;
int y_blocks = (src_ds->GetRasterYSize() + block_size - 1) / block_size;

for (int y_block = 0; y_block < y_blocks; y_block++) {
    for (int x_block = 0; x_block < x_blocks; x_block++) {
        int x_offset = x_block * block_size;
        int y_offset = y_block * block_size;
        int x_size = MIN(block_size, src_ds->GetRasterXSize() - x_offset);
        int y_size = MIN(block_size, src_ds->GetRasterYSize() - y_offset);

        GDALRasterBand *src_band = src_ds->GetRasterBand(1);
        GDALRasterBand *dst_band = dst_ds->GetRasterBand(1);

        float *buf = (float *) CPLMalloc(sizeof(float) * x_size * y_size);
        src_band->RasterIO(GF_Read, x_offset, y_offset, x_size, y_size,
                           buf, x_size, y_size, GDT_Float32, 0, 0);

        double *x = (double *) CPLMalloc(sizeof(double) * x_size * y_size);
        double *y = (double *) CPLMalloc(sizeof(double) * x_size * y_size);

        for (int j = 0; j < y_size; j++) {
            for (int i = 0; i < x_size; i++) {
                x[i + j * x_size] = src_geotransform[0] + (i + x_offset) * src_geotransform[1] +
                                    (j + y_offset) * src_geotransform[2];
                y[i + j * x_size] = src_geotransform[3] + (i + x_offset) * src_geotransform[4] +
                                    (j + y_offset) * src_geotransform[5];
            }
        }

        transform->Transform(x_size * y_size, x, y, buf);

        dst_band->RasterIO(GF_Write, x_offset, y_offset, x_size, y_size,
                           buf, x_size, y_size, GDT_Float32, 0, 0);

        CPLFree(buf);
        CPLFree(x);
        CPLFree(y);
    }
}

5. 保存目标影像的像素数据，并关闭数据集，例如：

dst_ds->SetGeoTransform(dst_geotransform);
dst_ds->SetProjection(dst_proj);

GDALClose(src_ds);
GDALClose(dst_ds);