Using GDALWarpAppOptionsNew for Raster Warping Operations

Answer:

GDALWarpAppOptionsNew is a function in the GDAL library that creates a new set of options for the gdalwarp utility. This function is part of the GDAL C API and is used to configure the parameters for warping operations, such as reprojection and resampling of raster data.

Here's a basic guide on how to use GDALWarpAppOptionsNew:

Include the necessary headers: Make sure to include the GDAL headers in your source file.
```
#include "gdal.h"
#include "gdal_utils.h"
```
Initialize GDAL: Before using any GDAL functions, you need to initialize the GDAL library.
```
GDALAllRegister();
```

Define the options: You need to define the options you want to pass to gdalwarp. These options are typically the same as the command-line options for gdalwarp.

const char *options[] = {
    "-t_srs", "EPSG:4326",  // Target spatial reference system
    "-r", "bilinear",       // Resampling method
    "-of", "GTiff",         // Output format
    NULL                    // Terminate the list with a NULL pointer
};

Create the options object: Use GDALWarpAppOptionsNew to create the options object.

GDALWarpAppOptions *psOptions = GDALWarpAppOptionsNew(options, NULL);
if (psOptions == NULL) {
    fprintf(stderr, "Failed to create GDALWarpAppOptions\n");
    return 1;
}

Open the input dataset: Open the input dataset using GDALOpen.

GDALDatasetH hSrcDS = GDALOpen("input.tif", GA_ReadOnly);
if (hSrcDS == NULL) {
    fprintf(stderr, "Failed to open input dataset\n");
    return 1;
}

Create the output dataset: You can create the output dataset using GDALWarp with the options object.

GDALDatasetH hDstDS = GDALWarp("output.tif", NULL, 1, &hSrcDS, psOptions, NULL);
if (hDstDS == NULL) {
    fprintf(stderr, "GDALWarp failed\n");
    return 1;
}

Clean up: Close the datasets and free the options object.

GDALClose(hSrcDS);
GDALClose(hDstDS);
GDALWarpAppOptionsFree(psOptions);

Here is the complete example code:

#include "gdal.h"
#include "gdal_utils.h"
#include <stdio.h>

int main() {
    // Initialize GDAL
    GDALAllRegister();

    // Define the options
    const char *options[] = {
        "-t_srs", "EPSG:4326",  // Target spatial reference system
        "-r", "bilinear",       // Resampling method
        "-of", "GTiff",         // Output format
        NULL                    // Terminate the list with a NULL pointer
    };

    // Create the options object
    GDALWarpAppOptions *psOptions = GDALWarpAppOptionsNew(options, NULL);
    if (psOptions == NULL) {
        fprintf(stderr, "Failed to create GDALWarpAppOptions\n");
        return 1;
    }

    // Open the input dataset
    GDALDatasetH hSrcDS = GDALOpen("input.tif", GA_ReadOnly);
    if (hSrcDS == NULL) {
        fprintf(stderr, "Failed to open input dataset\n");
        return 1;
    }

    // Create the output dataset
    GDALDatasetH hDstDS = GDALWarp("output.tif", NULL, 1, &hSrcDS, psOptions, NULL);
    if (hDstDS == NULL) {
        fprintf(stderr, "GDALWarp failed\n");
        return 1;
    }

    // Clean up
    GDALClose(hSrcDS);
    GDALClose(hDstDS);
    GDALWarpAppOptionsFree(psOptions);

    return 0;
}

This example demonstrates how to use GDALWarpAppOptionsNew to set up and execute a warping operation with GDAL. Adjust the options and file paths as needed for your

Using GDALWarpAppOptionsNew for Raster Warping Operations

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