sarlo.io¶

Common file read/write operations for working with radar data

`GeoXML` ¶

Stores spatial reference information from topophase XML data.

Attributes:

Name	Type	Description
`xmin`	`int`	longitude minimum
`ymin`	`int`	latitude minimum
`xmax`	`int`	longitude maximum
`ymax`	`int`	latitude maximum
`xres`		range resolution
`yres`		azimuth resolution
`width`	`int`	x pixel numbers
`height`	`int`	y pixel numbers
`bounds`	`list`	[ymax, ymin, xmin, xmax]

Source code in sarlo/io.py

class GeoXML(object):
    """Stores spatial reference information from topophase XML data.

    Attributes:
        xmin: longitude minimum
        ymin: latitude minimum
        xmax: longitude maximum
        ymax: latitude maximum
        xres: range resolution
        yres: azimuth resolution
        width: x pixel numbers
        height: y pixel numbers
        bounds: [ymax, ymin, xmin, xmax]
    """

    def __init__(self, xmlfile: str):
        """Stores geospatial information from isce raster xml files

        Args:
            xmlfile: ISCE .xml file for a given raster

        Returns:
            self: the Sentinel1 object.
        """

        self.ymax: int = None
        self.xmax: int = None
        self.ymin: int = None
        self.xmin: int = None
        self.ysize: int = None
        self.xsize: int = None
        self.height: int = None
        self.width: int = None
        self.bounds: list = []
        self.xmlfile: str = xmlfile

    def parser(self):
        """Returns spatial reference data from Sentinel-1 phase correction XML

        Args:
            xmlfile: Str path to an xml file

        Returns:
            self: object with the spatial reference data as attributes
        """

        tree = ET.parse(self.xmlfile)
        root = tree.getroot()

        # parse the tree to extract georeferencing info
        delta_array = np.array([])
        start_array = np.array([])
        size_array = np.array([], dtype=np.int32)
        for size in root.iter("property"):
            if size.items()[0][1] == "size":
                size_array = np.append(size_array, int(size.find("value").text))
        for delta_val in root.iter("property"):
            if delta_val.items()[0][1] == "delta":
                delta_array = np.append(
                    delta_array, float(delta_val.find("value").text)
                )
        for start_val in root.iter("property"):
            if start_val.items()[0][1] == "startingvalue":
                start_array = np.append(
                    start_array, float(start_val.find("value").text)
                )
        end_array = start_array + size_array * delta_array

        # use standard geospatial terminology to reference file sizes and spatial bounds
        self.ymax = max(start_array[1], end_array[1])
        self.ymin = min(start_array[1], end_array[1])
        self.xmax = max(start_array[0], end_array[0])
        self.xmin = min(start_array[0], end_array[0])
        self.bounds = [self.ymax, self.ymin, self.xmin, self.xmax]
        self.width = size_array[0]
        self.height = size_array[1]
        self.ysize = delta_array[1]
        self.xsize = delta_array[0]

`init(self, xmlfile)` `special` ¶

Stores geospatial information from isce raster xml files

Parameters:

Name	Type	Description	Default
`xmlfile`	`str`	ISCE .xml file for a given raster	required

Returns:

Type	Description
`self`	the Sentinel1 object.

Source code in sarlo/io.py

def __init__(self, xmlfile: str):
    """Stores geospatial information from isce raster xml files

    Args:
        xmlfile: ISCE .xml file for a given raster

    Returns:
        self: the Sentinel1 object.
    """

    self.ymax: int = None
    self.xmax: int = None
    self.ymin: int = None
    self.xmin: int = None
    self.ysize: int = None
    self.xsize: int = None
    self.height: int = None
    self.width: int = None
    self.bounds: list = []
    self.xmlfile: str = xmlfile

`parser(self)` ¶

Returns spatial reference data from Sentinel-1 phase correction XML

Parameters:

Name	Type	Description	Default
`xmlfile`		Str path to an xml file	required

Returns:

Type	Description
`self`	object with the spatial reference data as attributes

Source code in sarlo/io.py

def parser(self):
    """Returns spatial reference data from Sentinel-1 phase correction XML

    Args:
        xmlfile: Str path to an xml file

    Returns:
        self: object with the spatial reference data as attributes
    """

    tree = ET.parse(self.xmlfile)
    root = tree.getroot()

    # parse the tree to extract georeferencing info
    delta_array = np.array([])
    start_array = np.array([])
    size_array = np.array([], dtype=np.int32)
    for size in root.iter("property"):
        if size.items()[0][1] == "size":
            size_array = np.append(size_array, int(size.find("value").text))
    for delta_val in root.iter("property"):
        if delta_val.items()[0][1] == "delta":
            delta_array = np.append(
                delta_array, float(delta_val.find("value").text)
            )
    for start_val in root.iter("property"):
        if start_val.items()[0][1] == "startingvalue":
            start_array = np.append(
                start_array, float(start_val.find("value").text)
            )
    end_array = start_array + size_array * delta_array

    # use standard geospatial terminology to reference file sizes and spatial bounds
    self.ymax = max(start_array[1], end_array[1])
    self.ymin = min(start_array[1], end_array[1])
    self.xmax = max(start_array[0], end_array[0])
    self.xmin = min(start_array[0], end_array[0])
    self.bounds = [self.ymax, self.ymin, self.xmin, self.xmax]
    self.width = size_array[0]
    self.height = size_array[1]
    self.ysize = delta_array[1]
    self.xsize = delta_array[0]

`Sentinel1` ¶

Class description.

Attributes:

Name	Type	Description
`xml`	`str`	topsProc.xml file from ISCE processing
`res`	`int`	range pixel size
`lambda`		wavelength
`baseline`	`int`	distance between observation points (Satellite to Satellite)
`center_range`	`int`	range between the antenna's phase center and the point on the ground
`incid_angle`	`int`	The incidence angle is the angle defined by the incident radar beam and the vertical (normal) to the intercepting surface.

Source code in sarlo/io.py

class Sentinel1(object):
    """Class description.

    Attributes:
        xml: topsProc.xml file from ISCE processing
        res: range pixel size
        lambda: wavelength
        baseline: distance between observation points (Satellite to Satellite)
        center_range: range between the antenna's phase center and the point on the ground
        incid_angle:  The incidence angle is the angle defined by the incident radar beam and the vertical (normal) to the intercepting surface.
    """

    def __init__(self, xml: str):
        """Function description.

        Args:
            xml: some kind of xml file

        Returns:
            self: the Sentinel1 object.
        """

        self.xml: str = xml
        self.res: int = None
        self.llambda: int = None
        self.baseline: int = None
        self.center_range: int = None
        self.incid_angle: int = None

    def parse_xml(self):
        """Read Stripmap and TOPS xml files.

        Args:
            None.

        Returns:
            None. Updates the object attributes
        """

        tree = ET.parse(self.xml)
        root = tree.getroot()

        self.res = float(
            root.findall("./reference/instrument/range_pixel_size")[0].text
        )  # TOPS has
        self.llambda = float(
            root.findall("./reference/instrument/radar_wavelength")[0].text
        )  # TOPS has
        try:
            first_range = float(
                root.findall("./runTopo/inputs/range_first_sample")[0].text
            )
        except:
            first_range = float(
                root.findall("./runTopo/inputs/RANGE_FIRST_SAMPLE")[0].text
            )  # StartingRange is slant range to first pixel
        try:
            num_range_bin = int(root.findall("./runTopo/inputs/width")[0].text)
        except:
            num_range_bin = int(root.findall("./runTopo/inputs/WIDTH")[0].text)
        try:
            num_range_looks = int(
                root.findall("./runTopo/inputs/number_range_looks")[0].text
            )
        except:
            num_range_looks = int(
                root.findall("./runTopo/inputs/NUMBER_RANGE_LOOKS")[0].text
            )
        # Strange as the formula calls for the slant range not the center range. And this isn't how I would calculate center range either
        self.center_range = (
            first_range + (num_range_bin / 2 - 1) * self.res * num_range_looks
        )
        self.incid_angle = float(
            root.findall("./reference/instrument/incidence_angle")[0].text
        )
        baseline_top = float(root.findall("./baseline/perp_baseline_top")[0].text)
        baseline_bottom = float(root.findall("./baseline/perp_baseline_bottom")[0].text)
        self.baseline = (baseline_bottom + baseline_top) / 2

`init(self, xml)` `special` ¶

Function description.

Parameters:

Name	Type	Description	Default
`xml`	`str`	some kind of xml file	required

Returns:

Type	Description
`self`	the Sentinel1 object.

Source code in sarlo/io.py

def __init__(self, xml: str):
    """Function description.

    Args:
        xml: some kind of xml file

    Returns:
        self: the Sentinel1 object.
    """

    self.xml: str = xml
    self.res: int = None
    self.llambda: int = None
    self.baseline: int = None
    self.center_range: int = None
    self.incid_angle: int = None

`parse_xml(self)` ¶

Read Stripmap and TOPS xml files.

Returns:

Type	Description
	None. Updates the object attributes

Source code in sarlo/io.py

def parse_xml(self):
    """Read Stripmap and TOPS xml files.

    Args:
        None.

    Returns:
        None. Updates the object attributes
    """

    tree = ET.parse(self.xml)
    root = tree.getroot()

    self.res = float(
        root.findall("./reference/instrument/range_pixel_size")[0].text
    )  # TOPS has
    self.llambda = float(
        root.findall("./reference/instrument/radar_wavelength")[0].text
    )  # TOPS has
    try:
        first_range = float(
            root.findall("./runTopo/inputs/range_first_sample")[0].text
        )
    except:
        first_range = float(
            root.findall("./runTopo/inputs/RANGE_FIRST_SAMPLE")[0].text
        )  # StartingRange is slant range to first pixel
    try:
        num_range_bin = int(root.findall("./runTopo/inputs/width")[0].text)
    except:
        num_range_bin = int(root.findall("./runTopo/inputs/WIDTH")[0].text)
    try:
        num_range_looks = int(
            root.findall("./runTopo/inputs/number_range_looks")[0].text
        )
    except:
        num_range_looks = int(
            root.findall("./runTopo/inputs/NUMBER_RANGE_LOOKS")[0].text
        )
    # Strange as the formula calls for the slant range not the center range. And this isn't how I would calculate center range either
    self.center_range = (
        first_range + (num_range_bin / 2 - 1) * self.res * num_range_looks
    )
    self.incid_angle = float(
        root.findall("./reference/instrument/incidence_angle")[0].text
    )
    baseline_top = float(root.findall("./baseline/perp_baseline_top")[0].text)
    baseline_bottom = float(root.findall("./baseline/perp_baseline_bottom")[0].text)
    self.baseline = (baseline_bottom + baseline_top) / 2

`geo_data` ¶

Class description.

Attributes:

Name	Type	Description
`file`	`str`	raster file to pull geo_data from
`xmin`	`int`	longitude minimum
`ymin`	`int`	latitute minimum
`xmax`	`int`	longitude maximum
`ymax`	`int`	longitude minimum
`bounds`	`list`	[xmin, ymin, xmax, ymax]
`xsize`	`int`	range resolution
`ysize`	`int`	azimuth resolution
`width`	`int`	number of columns
`height`	`int`	number of rows
`crs`		coordinate resolution system

Source code in sarlo/io.py

class geo_data(object):
    """Class description.

    Attributes:
        file: raster file to pull geo_data from
        xmin: longitude minimum
        ymin: latitute minimum
        xmax: longitude maximum
        ymax: longitude minimum
        bounds: [xmin, ymin, xmax, ymax]
        xsize: range resolution
        ysize: azimuth resolution
        width: number of columns
        height: number of rows
        crs: coordinate resolution system
    """

    def __init__(self, file):
        """Create the geo_data reader object.

        Args:
            file: path to a raster file to open.

        Returns:
            self: the geo_data object.
        """

        self.file: str = file
        self.xmin: int = None
        self.ymin: int = None
        self.xmax: int = None
        self.ymax: int = None
        self.bounds: list = []
        self.xsize: int = None
        self.ysize: int = None
        self.width: int = None
        self.height: int = None
        self.crs = None

    def read_geotiff(self):
        """Reads raster spatial reference and projection data.

        Args:
            None.

        Returns:
            None. Updates the object's spatial attributes.
        """

        image = gdal.Open(self.file)
        self.width = image.RasterXSize
        self.height = image.RasterYSize

        xmin, xsize, xoff, ymax, yoff, ysize = image.GetGeoTransform()
        self.xmin = xmin
        self.xmax = xmin + xoff + (self.width * xsize)
        self.ymin = ymax + yoff + (self.height * ysize)
        self.ymax = ymax
        self.xsize = xsize
        self.ysize = ysize
        self.bounds = [self.xmin, self.ymin, self.xmax, self.ymax]

        proj = image.GetProjection()
        self.crs = proj.strip()

        # clear the file pointer to avoid memory issues
        image = None

`init(self, file)` `special` ¶

Create the geo_data reader object.

Parameters:

Name	Type	Description	Default
`file`		path to a raster file to open.	required

Returns:

Type	Description
`self`	the geo_data object.

Source code in sarlo/io.py

def __init__(self, file):
    """Create the geo_data reader object.

    Args:
        file: path to a raster file to open.

    Returns:
        self: the geo_data object.
    """

    self.file: str = file
    self.xmin: int = None
    self.ymin: int = None
    self.xmax: int = None
    self.ymax: int = None
    self.bounds: list = []
    self.xsize: int = None
    self.ysize: int = None
    self.width: int = None
    self.height: int = None
    self.crs = None

`read_geotiff(self)` ¶

Reads raster spatial reference and projection data.

Returns:

Type	Description
	None. Updates the object's spatial attributes.

Source code in sarlo/io.py

def read_geotiff(self):
    """Reads raster spatial reference and projection data.

    Args:
        None.

    Returns:
        None. Updates the object's spatial attributes.
    """

    image = gdal.Open(self.file)
    self.width = image.RasterXSize
    self.height = image.RasterYSize

    xmin, xsize, xoff, ymax, yoff, ysize = image.GetGeoTransform()
    self.xmin = xmin
    self.xmax = xmin + xoff + (self.width * xsize)
    self.ymin = ymax + yoff + (self.height * ysize)
    self.ymax = ymax
    self.xsize = xsize
    self.ysize = ysize
    self.bounds = [self.xmin, self.ymin, self.xmax, self.ymax]

    proj = image.GetProjection()
    self.crs = proj.strip()

    # clear the file pointer to avoid memory issues
    image = None

`write_geotiff(directory, outfilename, geo, data)` ¶

write geotiff file

Parameters:

Name	Type	Description	Default
`directory`	`str`	directory outfile is to be written to	required
`outfilename`	`str`	file name to be written	required
`geo`	`object`	geospatial object with crs and size attributes	required
`data`		2D array of spatial data	required

Return None. Writes geotiff

Source code in sarlo/io.py

def write_geotiff(directory: str, outfilename: str, geo: object, data):
    """write geotiff file

    Args:
        directory: directory outfile is to be written to
        outfilename: file name to be written
        geo: geospatial object with crs and size attributes
        data: 2D array of spatial data

    Return
        None. Writes geotiff
    """

    driver = gdal.GetDriverByName("GTiff")
    outRaster = driver.Create(directory + outfilename + ".tif", geo.height, geo.width)
    outRaster.SetGeoTransform([geo.xmin, geo.xsize, 0, geo.ymax, 0, geo.ysize])
    outband = outRaster.GetRasterBand(1)
    outband.WriteArray(data)
    outRasterSRS = osr.SpatialReference()
    outRasterSRS.ImportFromEPSG(4326)
    outRaster.SetProjection(outRasterSRS.ExportToWkt())
    outband.FlushCache()

`write_gif(data, directory, outfilename)` ¶

Write gif image file

Parameters:

Name	Type	Description	Default
`data`		2D array to be written as a gif	required
`directory`	`str`	directory in which file will be created	required
`outfilename`	`str`	name of file to be created	required

Returns:

Type	Description
	None.

Source code in sarlo/io.py

def write_gif(data, directory: str, outfilename: str):
    """Write gif image file

    Args:
        data: 2D array to be written as a gif
        directory: directory in which file will be created
        outfilename: name of file to be created

    Return:
        None.
    """
    (row, col) = data.shape
    data = data.flatten()
    # Get the nonzerp indices and min/max
    nz_IND = np.nonzero(data)
    nz_min = data[nz_IND[0]].min()
    nz_max = data[nz_IND[0]].max()
    # Set the scaled values
    data255 = data.copy()
    data255[nz_IND[0]] = (data[nz_IND[0]] - nz_min) * 255 / (nz_max - nz_min) + 1
    # Reshape the array of scaled values
    data255 = np.reshape(data255, (row, col))

    gif_img = Image.open(os.path.join(directory, outfilename + ".tif"))
    gif_img.save(os.path.join(directory, outfilename + ".gif"), "GIF", transparency=0)

`write_kml(directory, outfilename, geo, gif)` ¶

Writes kml overlay from gif file

Parameters:

Name	Type	Description	Default
`directory`	`str`	directory outfile is to be written to	required
`outfilename`	`str`	file name to be written	required
`geo`	`object`	geospatial object with crs and size attributes	required
`gif`	`str`	gif file to be written to kml	required

Return None. Writes geotiff

Source code in sarlo/io.py

def write_kml(directory: str, outfilename: str, geo: object, gif: str):
    """Writes kml overlay from gif file

    Args:
        directory: directory outfile is to be written to
        outfilename: file name to be written
        geo: geospatial object with crs and size attributes
        gif: gif file to be written to kml

    Return
        None. Writes geotiff
    """

    kml = simplekml.Kml()
    arraykml = kml.newgroundoverlay(name=outfilename)
    arraykml.icon.href = os.path.join(directory, gif)
    arraykml.latlonbox.north = geo.ymax
    arraykml.latlonbox.south = geo.ymin
    arraykml.latlonbox.east = geo.xmax
    arraykml.latlonbox.west = geo.xmin
    kml.save(os.path.join(directory, outfilename + ".kml"))

sarlo.io¶

GeoXML ¶

__init__(self, xmlfile) special ¶

parser(self) ¶

Sentinel1 ¶

__init__(self, xml) special ¶

parse_xml(self) ¶

geo_data ¶

__init__(self, file) special ¶

read_geotiff(self) ¶

write_geotiff(directory, outfilename, geo, data) ¶

write_gif(data, directory, outfilename) ¶

write_kml(directory, outfilename, geo, gif) ¶

`GeoXML` ¶

`init(self, xmlfile)` `special` ¶

`parser(self)` ¶

`Sentinel1` ¶

`init(self, xml)` `special` ¶

`parse_xml(self)` ¶

`geo_data` ¶

`init(self, file)` `special` ¶

`read_geotiff(self)` ¶

`write_geotiff(directory, outfilename, geo, data)` ¶

`write_gif(data, directory, outfilename)` ¶

`write_kml(directory, outfilename, geo, gif)` ¶