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raster

This module contains a set of functions to deal with GDAL datasets (rasters)

get_bbox_wgs84(raster)

Returns the bounding box from a raster.

Parameters:

Name Type Description Default
raster Union[Dataset, str, OTBObject]

raster filename (str) or GDAL dataset

 required

Returns:

Type Description
BoundingBox

a BoundingBox instance
Source code in scenes/raster.py 
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def get_bbox_wgs84(
        raster: Union[gdal.Dataset, str, pyotb.core.OTBObject]
) -> BoundingBox:
    """
    Returns the bounding box from a raster.

    Args:
        raster: raster filename (str) or GDAL dataset

    Returns:
        a BoundingBox instance

    """
    extent = get_extent_wgs84(raster)
    return coord_list_to_bbox(extent)

get_epsg(gdal_ds)

Get the EPSG code of a GDAL dataset

Parameters:

Name Type Description Default
gdal_ds Dataset

GDAL dataset

 required

Returns:

Type Description
int

EPSG code (int)
Source code in scenes/raster.py 
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def get_epsg(gdal_ds: gdal.Dataset) -> int:
    """
    Get the EPSG code of a GDAL dataset

    Args:
        gdal_ds: GDAL dataset

    Returns:
        EPSG code (int)

    """
    proj = osr.SpatialReference(wkt=gdal_ds.GetProjection())
    epsg = proj.GetAttrValue('AUTHORITY', 1)
    assert str(epsg).isdigit()
    return int(epsg)

get_epsg_extent_wgs84(filename)

Returns (epsg, extent_wgs84) from a raster file that GDAL can open.

Parameters:

Name Type Description Default
filename str

file name

 required

Returns:

Type Description
Tuple[int, Tuple[Tuple[float]]]

(epsg, extent_wgs84)
Source code in scenes/raster.py 
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def get_epsg_extent_wgs84(filename: str) -> Tuple[int, Tuple[Tuple[float]]]:
    """
    Returns (epsg, extent_wgs84) from a raster file that GDAL can open.

    Args:
        filename: file name

    Returns:
        (epsg, extent_wgs84)

    """
    gdal_ds = gdal.Open(filename)
    assert gdal_ds, f"File {filename} not accessible by GDAL"
    epsg = get_epsg(gdal_ds)
    extent_wgs84 = get_extent_wgs84(gdal_ds)

    return epsg, extent_wgs84

get_extent(raster)

Return list of corners coordinates from a raster

Parameters:

Name Type Description Default
raster Union[Dataset, str, OTBObject]

GDAL dataset, str (raster filename) or OTBObject

 required

Returns:

Type Description
Tuple[Tuple[float]]

list of coordinates
Source code in scenes/raster.py 
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def get_extent(
        raster: Union[gdal.Dataset, str, pyotb.core.OTBObject]
) -> Tuple[Tuple[float]]:
    """
    Return list of corners coordinates from a raster

    Args:
        raster: GDAL dataset, str (raster filename) or OTBObject

    Returns:
        list of coordinates

    """
    if isinstance(raster, pyotb.core.OTBObject):
        info = pyotb.ReadImageInfo(raster)
        spcx = info['spacingx']
        spcy = info['spacingy']
        orix = info['originx']
        oriy = info['originy']
        szx = info['sizex']
        szy = info['sizey']
        xmin = orix - .5 * spcx
        ymax = oriy - .5 * spcy
    else:
        gdal_ds = gdal.Open(raster) if isinstance(raster, str) else raster
        xmin, spcx, _, ymax, _, spcy = gdal_ds.GetGeoTransform()
        szx, szy = gdal_ds.RasterXSize, gdal_ds.RasterYSize
    xmax = xmin + szx * spcx
    ymin = ymax + szy * spcy

    return tuple([(xmin, ymax), (xmax, ymax), (xmax, ymin), (xmin, ymin)])

get_extent_wgs84(raster)

Returns the extent in WGS84 CRS from a raster

Parameters:

Name Type Description Default
raster Union[Dataset, str, OTBObject]

GDAL dataset, str (raster filename) or OTBObject

 required

Returns:

Name Type Description
extent Tuple[Tuple[float]]

coordinates in WGS84 CRS
Source code in scenes/raster.py 
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def get_extent_wgs84(
        raster: Union[gdal.Dataset, str, pyotb.core.OTBObject]
) -> Tuple[Tuple[float]]:
    """
    Returns the extent in WGS84 CRS from a raster

    Args:
        raster: GDAL dataset, str (raster filename) or OTBObject

    Returns:
        extent: coordinates in WGS84 CRS

    """
    coords = get_extent(raster)
    src_srs = osr.SpatialReference()
    projection = get_projection(raster)
    src_srs.ImportFromWkt(projection)
    tgt_srs = epsg2srs(4326)

    return reproject_coords(coords, src_srs, tgt_srs)

get_projection(raster)

Returns the projection (as str) of a raster.

Parameters:

Name Type Description Default
raster Union[Dataset, str, OTBObject]

GDAL dataset, str (raster filename) or OTBObject

 required

Returns:

Type Description
str

a str
Source code in scenes/raster.py 
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def get_projection(
        raster: Union[gdal.Dataset, str, pyotb.core.OTBObject]
) -> str:
    """
    Returns the projection (as str) of a raster.

    Args:
        raster: GDAL dataset, str (raster filename) or OTBObject

    Returns:
        a str

    """
    if isinstance(raster, pyotb.core.OTBObject):
        return pyotb.ReadImageInfo(raster)["projectionref"]
    gdal_ds = gdal.Open(raster) if isinstance(raster, str) else raster
    return gdal_ds.GetProjection()