def get_utm_wkt(coordinate, from_wkt):
'''
Function to return CRS for UTM zone of specified coordinates.
Used to transform coords to metres
@param coordinate: single coordinate pair
'''
def utm_getZone(longitude):
return (int(1 + (longitude + 180.0) / 6.0))
def utm_isNorthern(latitude):
if (latitude < 0.0):
return 0
else:
return 1
coordinate_array = np.array(coordinate).reshape((1, 2))
latlon_coord_trans = get_coordinate_transformation(from_wkt, 'EPSG:4326')
latlon_coord = coordinate if latlon_coord_trans is None else latlon_coord_trans.TransformPoints(
coordinate_array)[0][0:2]
# Set UTM coordinate reference system
utm_spatial_ref = SpatialReference()
utm_spatial_ref.SetWellKnownGeogCS('WGS84')
utm_spatial_ref.SetUTM(utm_getZone(latlon_coord[0]),
utm_isNorthern(latlon_coord[1]))
return utm_spatial_ref.ExportToWkt()
def alt_downloader(tile_nr_x, tile_nr_y):
# construct url
url = www_folder + str(tile_nr_x) + '/' + str(tile_nr_y) + '.asc.zip'
try:
# create a momemory driver and dataset on it
driver = gdal.GetDriverByName('MEM')
ds = driver.Create('', TD['NCOLS'], TD['NROWS'], 1, gdal.GDT_Float32)
# access the zip file
zf = ZipFile(BytesIO(requests.get(url).content))
# read the rasterfile in the format of an array
lines = zf.open(zf.infolist()[0]).readlines()
# NOTE:
# in the following lines we use some properties that the .asc files on our server have:
# - carriage returns are used to separate header items and rows
# - the header is 6 lines, that is, there is a NO DATA value in line 6
# - the data starts in line 7 (index 6)
# these are not required by the standard, c.f.
# http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/ESRI_ASCII_raster_format/009t0000000z000000/
# in particular, NO DATA is optional and carriage returns may be replaced by spaces
# read the geo transform
#as from http://geoexamples.blogspot.com/2012/01/creating-files-in-ogr-and-gdal-with.html:
#geotransform = (left x-coordinate, x-cellsize, rotation ?,upper y-coordinate,rotation,y-cellsize)
#Xgeo = geotransform[0] + Xpixel*geotransform[1] + Yline*geotransform[2]
#Ygeo = geotransform[3] + Xpixel*geotransform[4] + Yline*geotransform[5]
#for some reason, y-cellsize must be negative here
geo_trafo = (float(lines[2].split()[1]), TD['CELLSIZE'], 0,
float(lines[3].split()[1]) + TD['CELLSIZE'] * TD['NROWS'],
0, -TD['CELLSIZE'])
ds.SetGeoTransform(geo_trafo)
# read and write the data to the dataset
arr = list(map(lambda x: list(map(float, x.split())), lines[6:]))
zf.close()
band = ds.GetRasterBand(1)
band.WriteArray(array(arr))
# set the spatial reference system (probably not necessary)
proj = SpatialReference()
proj.SetWellKnownGeogCS("EPSG:31287")
ds.SetProjection(proj.ExportToWkt())
return ds
except:
return None
def __init__(self, filename=FILENAME):
print(f"[INFO] Reading geofile from '{filename}'")
self.dataset = gdal.Open(filename, gdal.GA_ReadOnly)
self.geotransform = self.dataset.GetGeoTransform()
self.band = self.dataset.GetRasterBand(1)
srcRef = SpatialReference()
srcRef.SetWellKnownGeogCS("WGS84")
dstRef = SpatialReference(self.dataset.GetProjection())
self.ct = CoordinateTransformation(srcRef, dstRef)
gdalVersion = osgeo.gdal.__version__
print(f"[INFO] Using gdal ver. {gdalVersion}")
self.gdalMajorVer = int(gdalVersion[:gdalVersion.find('.')])
def get_spatial_ref_from_wkt(wkt_or_crs_name):
'''
Function to return SpatialReference object for supplied WKT
@param wkt: Well-known text or CRS name for SpatialReference, including "EPSG:XXXX"
@return spatial_ref: SpatialReference from WKT
'''
spatial_ref = SpatialReference()
# Try to resolve WKT
result = spatial_ref.ImportFromWkt(wkt_or_crs_name)
if not result:
return spatial_ref
# Try to resolve CRS name - either mapped or original
result = spatial_ref.SetWellKnownGeogCS(
CRS_NAME_MAPPING.get(wkt_or_crs_name) or wkt_or_crs_name)
if not result:
return spatial_ref
# Try common formulations for UTM zones
#TODO: Fix this so it works in the Northern hemisphere
modified_crs_name = re.sub('\s+', '', wkt_or_crs_name.strip().upper())
utm_match = (re.match('(\w+)/MGAZONE(\d+)', modified_crs_name)
or re.match('(\w+)/(\d+)S', modified_crs_name)
or re.match('(EPSG:283)(\d{2})', modified_crs_name))
if utm_match:
modified_crs_name = utm_match.group(1)
utm_zone = int(utm_match.group(2))
result = spatial_ref.SetWellKnownGeogCS(
CRS_NAME_MAPPING.get(modified_crs_name) or modified_crs_name)
if not result:
spatial_ref.SetUTM(
utm_zone, False
) # Put this here to avoid potential side effects in downstream code
return spatial_ref
assert not result, 'Invalid WKT or CRS name'
def get_spatial_ref_from_wkt(wkt_or_crs_name):
'''
Function to return SpatialReference object for supplied WKT
@param wkt: Well-known text or CRS name for SpatialReference, including "EPSG:XXXX"
@return spatial_ref: SpatialReference from WKT
'''
if not wkt_or_crs_name:
return None
spatial_ref = SpatialReference()
result = spatial_ref.SetFromUserInput(wkt_or_crs_name)
if not result:
logger.debug(
'CRS determined using SpatialReference.SetFromUserInput({})'.
format(wkt_or_crs_name))
return spatial_ref
# Try to resolve WKT
result = spatial_ref.ImportFromWkt(wkt_or_crs_name)
if not result:
logger.debug(
'CRS determined using SpatialReference.ImportFromWkt({})'.format(
wkt_or_crs_name))
return spatial_ref
# Try to resolve CRS name - either mapped or original
modified_crs_name = CRS_NAME_MAPPING.get(
wkt_or_crs_name) or wkt_or_crs_name
result = spatial_ref.SetWellKnownGeogCS(modified_crs_name)
if not result:
logger.debug(
'CRS determined using SpatialReference.SetWellKnownGeogCS({})'.
format(modified_crs_name))
return spatial_ref
match = re.match('EPSG:(\d+)$', wkt_or_crs_name, re.IGNORECASE)
if match:
epsg_code = int(match.group(1))
result = spatial_ref.ImportFromEPSG(epsg_code)
if not result:
logger.debug(
'CRS determined using SpatialReference.ImportFromEPSG({})'.
format(epsg_code))
return spatial_ref
# Try common formulations for UTM zones
#TODO: Fix this so it works in the Northern hemisphere
modified_crs_name = re.sub('\s+', '', wkt_or_crs_name.strip().upper())
utm_match = (re.match('(\w+)/MGAZONE(\d+)$', modified_crs_name)
or re.match('(\w+)/(\d+)S$', modified_crs_name)
or re.match('(EPSG:283)(\d{2})$', modified_crs_name)
or re.match('(MGA)(\d{2}$)', modified_crs_name))
if utm_match:
modified_crs_name = utm_match.group(1)
modified_crs_name = CRS_NAME_MAPPING.get(
modified_crs_name) or modified_crs_name
utm_zone = int(utm_match.group(2))
result = spatial_ref.SetWellKnownGeogCS(modified_crs_name)
if not result:
spatial_ref.SetUTM(
utm_zone, False
) # Put this here to avoid potential side effects in downstream code
logger.debug(
'UTM CRS determined using SpatialReference.SetWellKnownGeogCS({}) (zone{})'
.format(modified_crs_name, utm_zone))
return spatial_ref
assert not result, 'Invalid WKT or CRS name: "{}"'.format(wkt_or_crs_name)
