# Source code for rios.imageio

```#!/usr/bin/env python

"""
This file contains definitions that are
common to all the image reading and
writing modules
"""
# This file is part of RIOS - Raster I/O Simplification
# Copyright (C) 2012  Sam Gillingham, Neil Flood
#
# This program is free software: you can redistribute it and/or modify
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import numpy
from osgeo import gdalconst

from . import rioserrors

INTERSECTION = 0
UNION = 1
BOUNDS_FROM_REFERENCE = 2       # Bounds of working region are taken from given reference grid

[docs]class Coord:
"""a simple class that contains one coord"""
def __init__(self, x, y):
self.x = x
self.y = y

[docs]def wld2pix(transform, geox, geoy):
"""converts a set of map coords to pixel coords"""
x = (transform * transform -
transform * transform + transform * geoy -
transform * geox) / (transform * transform - transform * transform)

y = (transform * transform - transform * transform -
transform * geoy + transform * geox) / (transform * transform - transform * transform)

return Coord(x, y)

[docs]def pix2wld(transform, x, y):
"""converts a set of pixels coords to map coords"""
geox = transform + transform * x + transform * y
geoy = transform + transform * x + transform * y

return Coord(geox, geoy)

# Mappings between numpy datatypes and GDAL datatypes.
# Note that ambiguities are resolved by the order - the first one found
# is the one chosen.
dataTypeMapping = [
(numpy.uint8, gdalconst.GDT_Byte),
(numpy.bool, gdalconst.GDT_Byte),
(numpy.int16, gdalconst.GDT_Int16),
(numpy.uint16, gdalconst.GDT_UInt16),
(numpy.int32, gdalconst.GDT_Int32),
(numpy.uint32, gdalconst.GDT_UInt32),
(numpy.single, gdalconst.GDT_Float32),
(numpy.float, gdalconst.GDT_Float64)
]

# hack for GDAL 3.5 and later which suppport 64 bit ints
if hasattr(gdalconst, 'GDT_Int64'):
dataTypeMapping.append((numpy.int64, gdalconst.GDT_Int64))
dataTypeMapping.append((numpy.uint64, gdalconst.GDT_UInt64))

[docs]def GDALTypeToNumpyType(gdaltype):
"""
Given a gdal data type returns the matching
numpy data type
"""
for (numpy_type, test_gdal_type) in dataTypeMapping:
if test_gdal_type == gdaltype:
return numpy_type
raise rioserrors.TypeConversionError("Unknown GDAL datatype: %s"%gdaltype)

[docs]def NumpyTypeToGDALType(numpytype):
"""
For a given numpy data type returns the matching
GDAL data type
"""
for (test_numpy_type, gdaltype) in dataTypeMapping:
if test_numpy_type == numpytype:
return gdaltype
raise rioserrors.TypeConversionError("Unknown numpy datatype: %s"%numpytype)
```