Utilities function to create a vector grid from raster, reproject raster and many others.

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reproject_raster

 reproject_raster (src_fname:str, dst_fname:str, dst_crs:str='EPSG:4326')

Reproject a GeoTiff file to specified crs

Type Default Details
src_fname str Source raster geotiff file
dst_fname str Destination raster geotiff file
dst_crs str EPSG:4326 EPSG code to project to
Returns None
Exported source 
def reproject_raster(src_fname:str, # Source raster geotiff file
                     dst_fname:str, # Destination raster geotiff file
                     dst_crs:str='EPSG:4326', # EPSG code to project to
                     ) -> None:
    "Reproject a GeoTiff file to specified crs"
    with rasterio.open(src_fname) as src:
        transform, width, height = calculate_default_transform(
            src.crs, dst_crs, src.width, src.height, *src.bounds)
        kwargs = src.meta.copy()
        kwargs.update({
            'crs': dst_crs,
            'transform': transform,
            'width': width,
            'height': height
        })

        with rasterio.open(dst_fname, 'w', **kwargs) as dst:
            for i in range(1, src.count + 1):
                reproject(
                    source=rasterio.band(src, i),
                    destination=rasterio.band(dst, i),
                    src_transform=src.transform,
                    src_crs=src.crs,
                    dst_transform=transform,
                    dst_crs=dst_crs,
                    resampling=Resampling.nearest)

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gridder

 gridder (fname_raster:str, band:int=1, nrows:int=10, ncols:int=10)

Generate a grid of polygons overlaid on a raster file.

Type Default Details
fname_raster str The path to the raster file.
band int 1 The band number to use. Defaults to 1.
nrows int 10 The number of rows in the grid. Defaults to 10.
ncols int 10 The number of columns in the grid. Defaults to 10.
Returns GeoDataFrame A GeoDataFrame of the grid cells geometry with ‘loc_id’ as index.
Exported source 
def gridder(
    fname_raster:str, # The path to the raster file.
    band:int=1, # The band number to use. Defaults to 1.
    nrows:int=10, # The number of rows in the grid. Defaults to 10.
    ncols:int=10, # The number of columns in the grid. Defaults to 10.
    ) -> gpd.GeoDataFrame: # A GeoDataFrame of the grid cells geometry with 'loc_id' as index.
    "Generate a grid of polygons overlaid on a raster file."
    with rasterio.open(fname_raster) as f:
        raster = f.read(band)
        bounds = f.bounds
        crs = f.crs.to_string()

    polygon = box(*bounds)
    gdf_polygon = gpd.GeoDataFrame([1], geometry=[polygon], crs=crs)

    # Calculate the bounds of the polygon
    minx, miny, maxx, maxy = polygon.bounds

    # Calculate the width and height of each cell
    cell_width = (maxx - minx) / ncols
    cell_height = (maxy - miny) / nrows

    # Create an empty list to hold the grid cells
    grid_cells = []

    # Generate the grid
    for i in range(ncols):
        for j in range(nrows):
            # Calculate the coordinates of the cell
            x1 = minx + i * cell_width
            y1 = miny + j * cell_height
            x2 = x1 + cell_width
            y2 = y1 + cell_height

            # Create a box for each cell
            cell = box(x1, y1, x2, y2)
            grid_cells.append(cell)

    # Create a GeoDataFrame from the grid cells
    grid = gpd.GeoDataFrame(grid_cells, columns=['geometry'], crs=crs)

    # Intersect the grid with the polygon
    gdf = gpd.overlay(grid, gdf_polygon, how='intersection').reset_index()
    gdf = gdf.drop(0, axis=1).set_index('index')
    gdf.index.name = 'loc_id'
    return gdf
fname_raster = './files/ground-truth-02-4326-simulated.tif'
print(gridder(fname_raster).head())
ax = gridder(fname_raster, nrows=10, ncols=10).boundary.plot(lw=0.5)
ax.axis('off');
                                                 geometry
loc_id                                                   
0       POLYGON ((-1.17017 43.02904, -1.17017 42.99324...
1       POLYGON ((-1.17017 43.06483, -1.17017 43.02904...
2       POLYGON ((-1.17017 43.10063, -1.17017 43.06483...
3       POLYGON ((-1.17017 43.13643, -1.17017 43.10063...
4       POLYGON ((-1.17017 43.17222, -1.17017 43.13643...

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anonymize_raster

 anonymize_raster (fname_raster:str, new_lon_origin:float,
                   new_lat_origin:float, band:int=1)

Anonymze a raster by translating it to specified location and values standardized.

Type Default Details
fname_raster str The path to the raster file.
new_lon_origin float Longitude of the new origin
new_lat_origin float Latitude of the new origin
band int 1 The band number to use. Defaults to 1.
Returns None
Exported source 
def anonymize_raster(fname_raster:str, # The path to the raster file.
                     new_lon_origin:float, # Longitude of the new origin
                     new_lat_origin:float, # Latitude of the new origin
                     band:int=1, # The band number to use. Defaults to 1.
                     ) -> None:
    "Anonymze a raster by translating it to specified location and values standardized."
    with rasterio.open(src_fname) as src:
        # Calculate the new transform based on the new origin and the same resolution
        new_transform = from_origin(new_lon_origin, new_lat_origin, src.res[0], src.res[1])
        profile = src.profile.copy()
        profile['transform'] = new_transform
        
        # Normalize values
        array = src.read(band)
        normalized_array = (array - array.min()) / (array.max() - array.min())
        
        with rasterio.open(dst_fname, 'w', **profile) as dst:
            dst.write(normalized_array, band)