def swap(data, outname):
"""
byte swapping from small to big endian (as required by GAMMA)
Parameters
----------
data: str
the DEM file to be swapped
outname: str
the name of the file to write
Returns
-------
"""
with raster.Raster(data) as ras:
dtype = ras.dtype
ras_format = ras.format
if ras_format != 'ENVI':
raise IOError('only ENVI format supported')
dtype_lookup = {'Int16': 2, 'CInt16': 2, 'Int32': 4, 'Float32': 4, 'CFloat32': 4, 'Float64': 8}
if dtype not in dtype_lookup:
raise IOError('data type {} not supported'.format(dtype))
disp.swap_bytes(infile=data,
outfile=outname,
swap_type=dtype_lookup[dtype])
with HDRobject(data + '.hdr') as header:
header.byte_order = 1
header.write(outname + '.hdr')
def makeSRTM(scenes, srtmdir, outname):
"""
Create a DEM in Gamma format from SRTM tiles
- coordinates are read to determine the required DEM extent and select the necessary hgt tiles
- mosaics SRTM DEM tiles, converts them to Gamma format and subtracts offset to WGS84 ellipsoid
intended for SRTM products downloaded from:
- USGS: https://gdex.cr.usgs.gov/gdex/
- CGIAR: http://srtm.csi.cgiar.org
Parameters
----------
scenes: list of str or pyroSAR.ID
a list of Gamma parameter files or pyroSAR ID objects to read the DEM extent from
srtmdir: str
a directory containing the SRTM hgt tiles
outname: str
the name of the final DEM file
Returns
-------
"""
tempdir = outname + '___temp'
os.makedirs(tempdir)
hgt_options = hgt(scenes)
hgt_files = finder(srtmdir, hgt_options)
nodatas = list(set([raster.Raster(x).nodata for x in hgt_files]))
if len(nodatas) == 1:
nodata = nodatas[0]
else:
raise RuntimeError('different nodata values are not permitted')
srtm_vrt = os.path.join(tempdir, 'srtm.vrt')
srtm_temp = srtm_vrt.replace('.vrt', '_tmp')
srtm_final = srtm_vrt.replace('.vrt', '')
gdalbuildvrt(hgt_files, srtm_vrt, {'srcNodata': nodata, 'options': ['-overwrite']})
gdal_translate(srtm_vrt, srtm_temp, {'format': 'ENVI', 'noData': nodata})
diff.srtm2dem(SRTM_DEM=srtm_temp,
DEM=srtm_final,
DEM_par=srtm_final + '.par',
gflg=2,
geoid='-',
outdir=tempdir)
shutil.move(srtm_final, outname)
shutil.move(srtm_final + '.par', outname + '.par')
par2hdr(outname + '.par', outname + '.hdr')
shutil.rmtree(tempdir)
def dempar(dem, logpath=None):
"""
create GAMMA parameter text files for DEM files
currently only EQA and UTM projections with WGS84 ellipsoid are supported
Parameters
----------
dem: str
the name of the DEM
logpath: str
a directory to write logfiles to
Returns
-------
"""
rast = raster.Raster(dem)
# determine data type
dtypes = {'Int16': 'INTEGER*2', 'UInt16': 'INTEGER*2', 'Float32': 'REAL*4'}
if rast.dtype not in dtypes:
raise IOError('data type not supported')
else:
dtype = dtypes[rast.dtype]
# format pixel posting and top left coordinate
posting = str(rast.geo['yres']) + ' ' + str(rast.geo['xres'])
latlon = str(rast.geo['ymax']) + ' ' + str(rast.geo['xmin'])
# evaluate projection
projections = {'longlat': 'EQA', 'utm': 'UTM'}
if rast.proj4args['proj'] not in projections:
raise ValueError('projection not supported (yet)')
else:
projection = projections[rast.proj4args['proj']]
# get ellipsoid
ellipsoid = rast.proj4args['ellps'] if 'ellps' in rast.proj4args else rast.proj4args['datum']
if ellipsoid != 'WGS84':
raise ValueError('ellipsoid not supported (yet)')
# create list for GAMMA command input
if projection == 'UTM':
zone = rast.proj4args['zone']
falsenorthing = 10000000. if rast.geo['ymin'] < 0 else 0
parlist = [projection, ellipsoid, 1, zone, falsenorthing, os.path.basename(dem),
dtype, 0, 1, rast.cols, rast.rows, posting, latlon]
else:
parlist = [projection, ellipsoid, 1, os.path.basename(dem), dtype,
0, 1, rast.cols, rast.rows, posting, latlon]
# execute GAMMA command
diff.create_dem_par(DEM_par=os.path.splitext(dem)[0] + '.par',
inlist=parlist,
outdir=os.path.dirname(dem),
logpath=logpath)
def mosaic(demlist, outname, byteorder=1, gammapar=True):
"""
mosaicing of multiple DEMs
Parameters
----------
demlist: list
a list of DEM names to be mosaiced
outname: str
the name of the final mosaic file
byteorder: {0, 1}
the byte order of the mosaic
- 0: small endian
- 1: big endian
gammapar: bool
create a Gamma parameter file for the mosaic?
Returns
-------
"""
if len(demlist) < 2:
raise IOError('length of demlist < 2')
with raster.Raster(demlist[0]) as ras:
nodata = ras.nodata
par = {
'format': 'ENVI',
'srcNodata': nodata,
' dstNodata': nodata,
'options': ['-q']
}
gdalwarp(demlist, outname, par)
if byteorder == 1:
swap(outname, outname + '_swap')
for item in [outname, outname + '.hdr', outname + '.aux.xml']:
os.remove(item)
os.rename(outname + '_swap', outname)
os.rename(outname + '_swap.hdr', outname + '.hdr')
if gammapar:
dempar(outname)
def mosaic(demlist, outname, byteorder=1, gammapar=True):
"""
mosaicing of multiple DEMs
"""
if len(demlist) < 2:
raise IOError('length of demlist < 2')
nodata = str(raster.Raster(demlist[0]).nodata)
run([
'gdalwarp', '-q', '-of', 'ENVI', '-srcnodata', nodata, '-dstnodata',
nodata, demlist, outname
])
if byteorder == 1:
swap(outname, outname + '_swap')
for item in [outname, outname + '.hdr', outname + '.aux.xml']:
os.remove(item)
os.rename(outname + '_swap', outname)
os.rename(outname + '_swap.hdr', outname + '.hdr')
if gammapar:
dempar(outname)
def makeSRTM(scenes, srtmdir, outname):
"""
Create a DEM from SRTM tiles
Input is a list of pyroSAR.ID objects from which coordinates are read to determine the required DEM extent
Mosaics SRTM DEM tiles, converts them to Gamma format and subtracts offset to WGS84 ellipsoid
for DEMs downloaded from USGS http://gdex.cr.usgs.gov or CGIAR http://srtm.csi.cgiar.org
"""
tempdir = outname + '___temp'
os.makedirs(tempdir)
hgt_options = hgt(scenes)
hgt_files = finder(srtmdir, hgt_options)
# todo: check if really needed
nodatas = [str(int(raster.Raster(x).nodata)) for x in hgt_files]
srtm_vrt = os.path.join(tempdir, 'srtm.vrt')
srtm_temp = srtm_vrt.replace('.vrt', '_tmp')
srtm_final = srtm_vrt.replace('.vrt', '')
run([
'gdalbuildvrt', '-overwrite', '-srcnodata', ' '.join(nodatas),
srtm_vrt, hgt_files
])
run([
'gdal_translate', '-of', 'ENVI', '-a_nodata', -32768, srtm_vrt,
srtm_temp
])
process(['srtm2dem', srtm_temp, srtm_final, srtm_final + '.par', 2, '-'],
outdir=tempdir)
shutil.move(srtm_final, outname)
shutil.move(srtm_final + '.par', outname + '.par')
hdr(outname + '.par')
shutil.rmtree(tempdir)
def swap(data, outname):
"""
byte swapping from small to big endian (as required by GAMMA)
"""
rast = raster.Raster(data)
dtype = rast.dtype
if rast.format != 'ENVI':
raise IOError('only ENVI format supported')
dtype_lookup = {
'Int16': 2,
'CInt16': 2,
'Int32': 4,
'Float32': 4,
'CFloat32': 4,
'Float64': 8
}
if dtype not in dtype_lookup:
raise IOError('data type {} not supported'.format(dtype))
process(['swap_bytes', data, outname, str(dtype_lookup[dtype])])
header = HDRobject(data + '.hdr')
header.byte_order = 1
hdr(header, outname + '.hdr')
