Thuban/Model/proj.py

# Copyright (c) 2001, 2003 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

__version__ = "$Revision$"

from Thuban import _

from types import StringTypes

import Projection
BaseProjection = Projection.Projection
del Projection

PROJ_UNITS_METERS  = 1
PROJ_UNITS_DEGREES = 2

class Projection(BaseProjection):

    """A proj4 projection object that remembers the parameters"""

    def __init__(self, params, name = None, epsg = None):
        """Initialize the Projection

        Parameters:

        params -- a list of 'parameter=value' strings

        name -- (optional) The name of the projectin. If None or omitted
                it defaults to 'Unknown' in the local language.

        epsg -- (optional) The EPSG code as a string.
        """
        BaseProjection.__init__(self, params)

        if name is None:
            self.name = _("Unknown")
        elif isinstance(name, StringTypes):
            self.name = name

        self.epsg = epsg
        self.params = params

    def ForwardBBox(self, bbox):
        """Return the bounding box of the corners of the bounding box bbox
        """
        # This is not really the correct way to determine the bbox of a
        # projected shape, but for now it works well enough
        llx, lly, urx, ury = bbox
        xs = []; ys = []
        x, y = self.Forward(llx, lly)
        xs.append(x); ys.append(y)
        x, y = self.Forward(llx, ury)
        xs.append(x); ys.append(y)
        x, y = self.Forward(urx, ury)
        xs.append(x); ys.append(y)
        x, y = self.Forward(urx, lly)
        xs.append(x); ys.append(y)
        
        return min(xs), min(ys), max(xs), max(ys)

    def GetName(self):
        """Return the name of the projection."""
        return self.name

    def Label(self):
        if self.epsg:
            return "EPSG % 5s %s" % (self.epsg, self.name)
        return self.name

    def EPSGCode(self):
        """Return the EPSG code as a string or None if there is none"""
        return self.epsg

    def GetParameter(self, param):
        """Return the projection value for the given parameter.

        If 'param' exists as a valid parameter return the associated
        value as a string. If the parameter does not have a value (like
        e.g. the 'south' parameter for utm) then the value is the
        parameter name itself.

        If the parameter doesn't exist return an empty string.
        """

        for pair in self.params:
            if "=" in pair:
                p, v = pair.split("=")
            else:
                p = v = pair
            if p == param:
                return v

        return ""

    def GetAllParameters(self):
        """Return list of 'parameter=value' strings"""
        return self.params

    def GetProjectedUnits(self):
        if self.GetParameter("proj") == "latlong":
            return PROJ_UNITS_DEGREES
        else:
            return PROJ_UNITS_METERS

    def __repr__(self):
        return self.name + ": " + repr(self.params)


class ProjFile:

    def __init__(self, filename):
        """Intialize the ProjFile.

        filename -- name of the file that this ProjFile represents.
        """

        self.__projs = []

        self.SetFilename(filename)
    
    def Add(self, proj):
        """Add the projection to the end of the file."""
        self.__projs.append(proj)

    def Remove(self, proj):
        """Remove the object proj from the projection file.

        Raises a ValueError is proj is not found.
        """

        self.__projs.remove(proj)

    def Replace(self, oldproj, newproj):
        """Replace the object 'oldproj' with 'newproj'.
        
        Raises ValueError if oldproj is not in the file.
        """

        #
        # see if the projection already exists.
        # this only works if Projection doesn't override __eq__
        #
        self.__projs[self.__projs.index(oldproj)] = newproj

    def GetFilename(self):
        """Return the filename where the ProjFile was read or will be
        written to.
        """

        return self.__filename

    def SetFilename(self, filename):
        """Set the filename where the ProjFile will be written to."""
        self.__filename = filename

    def GetProjections(self):
        """Return a list of the projections in the order they were read
        from the file or will be written.

        This is not a deep copy list, so any modifications made to the
        Projection objects will be written to the file.
        """

        return self.__projs

1	bh	1797	# Copyright (c) 2001, 2003 by Intevation GmbH
2	bh	6	# Authors:
3			# Bernhard Herzog <[email protected]>
4			#
5			# This program is free software under the GPL (>=v2)
6			# Read the file COPYING coming with Thuban for details.
7
8			__version__ = "$Revision$"
9
10	jonathan	745	from Thuban import _
11
12	jonathan	726	from types import StringTypes
13
14	bh	6	import Projection
15			BaseProjection = Projection.Projection
16			del Projection
17
18	jonathan	1250	PROJ_UNITS_METERS = 1
19			PROJ_UNITS_DEGREES = 2
20
21	bh	6	class Projection(BaseProjection):
22
23			"""A proj4 projection object that remembers the parameters"""
24
25	bh	1815	def __init__(self, params, name = None, epsg = None):
26			"""Initialize the Projection
27
28			Parameters:
29
30			params -- a list of 'parameter=value' strings
31
32			name -- (optional) The name of the projectin. If None or omitted
33			it defaults to 'Unknown' in the local language.
34
35			epsg -- (optional) The EPSG code as a string.
36	jonathan	745	"""
37	bh	6	BaseProjection.__init__(self, params)
38	jonathan	745
39	jonathan	758	if name is None:
40			self.name = _("Unknown")
41			elif isinstance(name, StringTypes):
42			self.name = name
43	jonathan	745
44	bh	1815	self.epsg = epsg
45	jonathan	758	self.params = params
46
47	bh	6	def ForwardBBox(self, bbox):
48			"""Return the bounding box of the corners of the bounding box bbox
49			"""
50			# This is not really the correct way to determine the bbox of a
51			# projected shape, but for now it works well enough
52			llx, lly, urx, ury = bbox
53			xs = []; ys = []
54			x, y = self.Forward(llx, lly)
55			xs.append(x); ys.append(y)
56			x, y = self.Forward(llx, ury)
57			xs.append(x); ys.append(y)
58			x, y = self.Forward(urx, ury)
59			xs.append(x); ys.append(y)
60			x, y = self.Forward(urx, lly)
61			xs.append(x); ys.append(y)
62	jonathan	758
63	bh	6	return min(xs), min(ys), max(xs), max(ys)
64	jonathan	695
65			def GetName(self):
66	jonathan	738	"""Return the name of the projection."""
67	jonathan	695	return self.name
68
69	bh	1815	def Label(self):
70			if self.epsg:
71			return "EPSG % 5s %s" % (self.epsg, self.name)
72			return self.name
73
74			def EPSGCode(self):
75			"""Return the EPSG code as a string or None if there is none"""
76			return self.epsg
77
78	jonathan	708	def GetParameter(self, param):
79	jonathan	738	"""Return the projection value for the given parameter.
80	jonathan	708
81	bh	1797	If 'param' exists as a valid parameter return the associated
82			value as a string. If the parameter does not have a value (like
83			e.g. the 'south' parameter for utm) then the value is the
84			parameter name itself.
85
86			If the parameter doesn't exist return an empty string.
87	jonathan	738	"""
88
89	jonathan	708	for pair in self.params:
90	bh	1797	if "=" in pair:
91			p, v = pair.split("=")
92			else:
93			p = v = pair
94	jonathan	708	if p == param:
95			return v
96
97			return ""
98
99			def GetAllParameters(self):
100	jonathan	738	"""Return list of 'parameter=value' strings"""
101	jonathan	695	return self.params
102
103	jonathan	1250	def GetProjectedUnits(self):
104			if self.GetParameter("proj") == "latlong":
105			return PROJ_UNITS_DEGREES
106			else:
107			return PROJ_UNITS_METERS
108
109	jonathan	695	def __repr__(self):
110	jonathan	726	return self.name + ": " + repr(self.params)
111	jonathan	695
112	bh	1815
113	jonathan	695	class ProjFile:
114
115			def __init__(self, filename):
116	jonathan	738	"""Intialize the ProjFile.
117	jonathan	695
118	jonathan	738	filename -- name of the file that this ProjFile represents.
119			"""
120
121			self.__projs = []
122
123			self.SetFilename(filename)
124	jonathan	695
125			def Add(self, proj):
126	bh	1802	"""Add the projection to the end of the file."""
127			self.__projs.append(proj)
128	jonathan	695
129	jonathan	726	def Remove(self, proj):
130	jonathan	758	"""Remove the object proj from the projection file.
131	jonathan	726
132	jonathan	738	Raises a ValueError is proj is not found.
133			"""
134	jonathan	695
135	jonathan	738	self.__projs.remove(proj)
136	jonathan	695
137	jonathan	758	def Replace(self, oldproj, newproj):
138			"""Replace the object 'oldproj' with 'newproj'.
139
140			Raises ValueError if oldproj is not in the file.
141			"""
142
143			#
144			# see if the projection already exists.
145			# this only works if Projection doesn't override __eq__
146			#
147			self.__projs[self.__projs.index(oldproj)] = newproj
148
149	jonathan	738	def GetFilename(self):
150			"""Return the filename where the ProjFile was read or will be
151			written to.
152			"""
153
154			return self.__filename
155
156			def SetFilename(self, filename):
157			"""Set the filename where the ProjFile will be written to."""
158			self.__filename = filename
159
160	jonathan	695	def GetProjections(self):
161	jonathan	738	"""Return a list of the projections in the order they were read
162			from the file or will be written.
163
164			This is not a deep copy list, so any modifications made to the
165			Projection objects will be written to the file.
166			"""
167
168			return self.__projs
169
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svn:keywords	Author Date Id Revision