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Overhauled GDAL export functionality and interface.
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@tcld
tcld committed Oct 30, 2015
1 parent 56e8dba commit a770967
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Showing 2 changed files with 97 additions and 45 deletions.
24 changes: 10 additions & 14 deletions worldengine/cli/main.py
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Original file line number Diff line number Diff line change
Expand Up @@ -341,18 +341,13 @@ def main():
# -----------------------------------------------------
export_options = parser.add_argument_group(
"Export Options", "You can specify the formats you wish the generated output to be in. ")
export_options.add_argument("--export-type", dest="export_type",
help="Export to a specific format such as: BMP or PNG",
default="bmp")
export_options.add_argument("--export-bpp", dest="export_bpp", type=int,
help="Bits per pixel: 8, 16 and 32",
default=8)
export_options.add_argument("--export-signed", dest="export_signed", action="store_true",
help="Used signed bits or not.",
default=False)
export_options.add_argument("--normalize", dest="export_normalize", action="store_true",
help="Normalize data to the min and max of your bpp choice.",
default=False)
export_options.add_argument("--export-format", dest="export_format", type=str,
help="Export to a specific format such as BMP or PNG. " +
"See http://www.gdal.org/formats_list.html for possible formats.",
default="PNG")
export_options.add_argument("--export-datatype", dest="export_datatype", type=str,
help="Type of stored data, e.g. uint16, int32, float32 etc.",
default="uint16")

args = parser.parse_args()

Expand All @@ -371,7 +366,7 @@ def main():
sys.setrecursionlimit(args.recursion_limit)

if args.number_of_plates < 1 or args.number_of_plates > 100:
usage(error="Number of plates should be a in [1, 100]")
usage(error="Number of plates should be in [1, 100]")

operation = "world"
if args.OPERATOR is None:
Expand Down Expand Up @@ -498,7 +493,8 @@ def main():
elif operation == 'export':
world = load_world(args.FILE)
print_world_info(world)
export(world, args.export_type, args.export_bpp, args.export_signed, args.export_normalize)
export(world, args.export_format, args.export_datatype,
path = '%s/%s_elevation' % (args.output_dir, world_name))
else:
raise Exception(
'Unknown operation: valid operations are %s' % OPERATIONS)
Expand Down
118 changes: 87 additions & 31 deletions worldengine/imex/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,65 +12,121 @@
import sys


def export(world, export_type, export_bpp, export_signed, export_normalize):
'''
Whenever a GDAL short-format (http://www.gdal.org/formats_list.html) is given
and a unique mapping to a file suffix exists, it is looked up in gdal_mapper.
Trivial ones (i.e. a call to lower() does the job) are not handled:
BAG, BMP, BT, ECW, ERS, FITS, GIF, GTA, PNG, RIK, VRT, XPM
All other formats (>100) currently end up with their respective GDAL short-format
converted to lower-case and might need to be renamed by the user.
'''
gdal_mapper = { # TODO: Find a way to make GDAL provide this mapping.
"aig" : "adf",
"bsb" : "kap",
"doq1" : "doq",
"doq2" : "doq",
"esat" : "n1",
"grib" : "grb",
"gtiff" : "tif",
"hfa" : "img",
"jdem" : "mem",
"jpeg" : "jpg",
"msgn" : "nat",
"terragen": "ter",
"usgsdem" : "dem",
}


def export(world, export_filetype = 'GTiff', export_datatype = 'float32', path = 'seed_output'):
try:
gdal
except NameError:
print("Cannot export: please install pygdal.")
sys.exit(1)

final_driver = gdal.GetDriverByName(export_type)
final_driver = gdal.GetDriverByName(export_filetype)
if final_driver is None:
print("%s driver not registered." % export_type)
print("%s driver not registered." % export_filetype)
sys.exit(1)

if export_bpp == 8 and export_signed:
numpy_type = numpy.int8
gdal_type = gdal.GDT_Byte
elif export_bpp == 8 and not export_signed:
# try to find the proper file-suffix
export_filetype = export_filetype.lower()
if export_filetype in gdal_mapper:
export_filetype = gdal_mapper[export_filetype]

# Note: GDAL will throw informative errors on its own whenever file type and data type cannot be matched.

# translate export_datatype; http://www.gdal.org/gdal_8h.html#a22e22ce0a55036a96f652765793fb7a4
export_datatype = export_datatype.lower()
if export_datatype in ['gdt_byte', 'uint8', 'int8', 'byte', 'char']: # GDAL does not support int8
bpp, signed, normalize = (8, False, True)
numpy_type = numpy.uint8
gdal_type = gdal.GDT_Byte
elif export_bpp == 16 and export_signed:
numpy_type = numpy.int16
gdal_type = gdal.GDT_Int16
elif export_bpp == 16 and not export_signed:
gdal_type = gdal.GDT_Byte
elif export_datatype in ['gdt_uint16', 'uint16']:
bpp, signed, normalize = (16, False, True)
numpy_type = numpy.uint16
gdal_type = gdal.GDT_UInt16
elif export_bpp == 32 and export_signed:
numpy_type = numpy.int32
gdal_type = gdal.GDT_Int32
elif export_bpp == 32 and not export_signed:
gdal_type = gdal.GDT_UInt16
elif export_datatype in ['gdt_uint32', 'uint32']:
bpp, signed, normalize = (32, False, True)
numpy_type = numpy.uint32
gdal_type = gdal.GDT_UInt32
gdal_type = gdal.GDT_UInt32
elif export_datatype in ['gdt_int16', 'int16']:
bpp, signed, normalize = (16, True, True)
numpy_type = numpy.int16
gdal_type = gdal.GDT_Int16
elif export_datatype in ['gdt_int32', 'int32', 'int']: # fallback for 'int'
bpp, signed, normalize = (32, True, True)
numpy_type = numpy.int32
gdal_type = gdal.GDT_Int32
elif export_datatype in ['gdt_float32', 'float32', 'float']: # fallback for 'float'
bpp, signed, normalize = (32, True, False)
numpy_type = numpy.float32
gdal_type = gdal.GDT_Float32
elif export_datatype in ['gdt_float64', 'float64']:
bpp, signed, normalize = (64, True, False)
numpy_type = numpy.float64
gdal_type = gdal.GDT_Float64
else:
print ("BPP %d is not valid, we only support 8, 16 and 32." % export_bpp)
sys.exit(1)
raise TypeError("Type of data not recognized or not supported by GDAL: %s" % export_datatype)

# massage data to scale between the absolute min and max
elevation = numpy.array(world.elevation['data'])
elevation = numpy.copy(world.elevation['data'])

if not export_signed and elevation.min() < 0.0:
elevation += abs(elevation.min()) # TODO: need better way to handle negative numbers
# shift data according to minimum possible value
if signed:
elevation = elevation - world.sea_level() # elevation 0.0 now refers to sea-level
else:
elevation -= elevation.min() # lowest point at 0.0

if export_normalize:
if export_signed:
elevation *= (((2**export_bpp)/2)-1)/elevation.max()
# rescale data (currently integer-types only)
if normalize:
# elevation maps usually have a range of 0 to 10, maybe 15 - rescaling for integers is essential
if signed:
elevation *= (2**(bpp - 1) - 1) / max(abs(elevation.min(), abs(elevation.max())))
else:
elevation *= (2**export_bpp)/elevation.max()
elevation *= (2**bpp - 1) / abs(elevation.max())

# round data (integer-types only)
if numpy_type != numpy.float32 and numpy_type != numpy.float64:
elevation = elevation.round()

# switch to final data type; no rounding performed
elevation = elevation.astype(numpy_type)

# take elevation data and push it into an intermediate GTiff format
# take elevation data and push it into an intermediate GTiff format (some formats don't support being written by Create())
inter_driver = gdal.GetDriverByName("GTiff")
_, inter_file = tempfile.mkstemp()
initial_ds = inter_driver.Create(inter_file, world.height, world.width, 1, gdal_type)
_, inter_file = tempfile.mkstemp() # returns: (file-handle, absolute path)
initial_ds = inter_driver.Create(inter_file, world.width, world.height, 1, gdal_type)
band = initial_ds.GetRasterBand(1)

band.WriteArray(elevation)
band = None # dereference band
initial_ds = None # save/flush and close

# take the intermediate GTiff format and convert to final format
initial_ds = gdal.Open(inter_file)
final_driver.CreateCopy('seed_output-%d.%s' % (export_bpp, export_type), initial_ds)
final_driver.CreateCopy('%s-%d.%s' % (path, bpp, export_filetype), initial_ds)

os.remove(inter_file)

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