/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/proj.py
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revision 758 by jonathan, Tue Apr 29 09:01:12 2003 UTC revision 2708 by bernhard, Sun Sep 24 20:01:23 2006 UTC
# Line 1  Line 1 
1  # Copyright (c) 2001 by Intevation GmbH  # Copyright (c) 2001, 2003, 2006 by Intevation GmbH
2  # Authors:  # Authors:
3  # Bernhard Herzog <[email protected]>  # Bernhard Herzog <[email protected]>
4    # Bernhard Reiter <[email protected]>
5  #  #
6  # This program is free software under the GPL (>=v2)  # This program is free software under the GPL (>=v2)
7  # Read the file COPYING coming with Thuban for details.  # Read the file COPYING coming with Thuban for details.
   
8  __version__ = "$Revision$"  __version__ = "$Revision$"
9    
 from Thuban import _  
   
10  from types import StringTypes  from types import StringTypes
11    import locale
12    
13    from Thuban import _
14    from Thuban.Lib.connector import Publisher
15    
16  import Projection  import Projection
17  BaseProjection = Projection.Projection  BaseProjection = Projection.Projection
18  del Projection  del Projection
19    
20    from messages import PROJECTION_ADDED, PROJECTION_REPLACED, PROJECTION_REMOVED
21    
22    PROJ_UNITS_METERS  = 1
23    PROJ_UNITS_DEGREES = 2
24    
25    def _do_we_have_to_work_around_broken_proj():
26        """ If we have a problematic locale, check if proj results are good. """
27        if locale.localeconv()['decimal_point'] != '.':
28            params = ["proj=latlong", "to_meter=0.01745", "ellps=clrk66"]
29            proj = BaseProjection(params)
30            result1 = proj.Forward(1,1)
31    
32            savedlocale = locale.getlocale(locale.LC_NUMERIC)
33            locale.setlocale(locale.LC_NUMERIC, "C")
34    
35            proj = BaseProjection(params)
36            result2 = proj.Forward(1,1)
37    
38            try:
39                locale.setlocale(locale.LC_NUMERIC, savedlocale)
40            except:
41                # python under some circumstances (observed 2.3.5-2 Debian Sarge)
42                # does not accept savedlocale directly
43                # deviating from the documentation
44                locale.setlocale(locale.LC_NUMERIC, savedlocale[0])
45            if result1 != result2:
46                return True
47        return False
48    
49  class Projection(BaseProjection):  class Projection(BaseProjection):
50        """A proj4 projection object that remembers the parameters.
51    
52        The proj library is not robust against decimal_point != '.' locales.
53        Since python 2.4 calls C extensions with the set locale, it can create
54        a problem.  It seems that calling
55            self.assuregoodlocale()
56            self.assureinitlocale()
57        before BaseProjection.__init__() is enough to work around this.
58    
59        We assuming that the locale stays the same after a projection
60        has been initialised
61        and thus we can return to it in self.assureinitlocale().
62        """
63    
64        def __init__(self, params, name = None, epsg = None):
65            """Initialize the Projection
66    
67      """A proj4 projection object that remembers the parameters"""          Parameters:
68    
69      def __init__(self, params, name = None):          params -- a list of 'parameter=value' strings
70          """Initialize the Projection with a list of  
71          'parameter=value' strings and an optional name. If 'name' is          name -- (optional) The name of the projection. If None or omitted
72          None, the name will be set to 'Unknown' in the local language.                  it defaults to 'Unknown' in the local language.
73    
74            epsg -- (optional) The EPSG code as a string.
75          """          """
76            self.initlocale = locale.getlocale(locale.LC_NUMERIC)
77            self.work_around_broken_proj = _do_we_have_to_work_around_broken_proj()
78    
79            self.assuregoodlocale()
80          BaseProjection.__init__(self, params)          BaseProjection.__init__(self, params)
81            self.assureinitlocale()
82    
83          if name is None:          if name is None:
84              self.name = _("Unknown")              self.name = _("Unknown")
85          elif isinstance(name, StringTypes):          elif isinstance(name, StringTypes):
86              self.name = name              self.name = name
87    
88            self.epsg = epsg
89          self.params = params          self.params = params
90    
91      def ForwardBBox(self, bbox):      def assuregoodlocale(self):
92          """Return the bounding box of the corners of the bounding box bbox          if self.work_around_broken_proj:
93          """              locale.setlocale(locale.LC_NUMERIC, "C")
94    
95        def assureinitlocale(self):
96            if self.work_around_broken_proj:
97                locale.setlocale(locale.LC_NUMERIC, self.initlocale)
98    
99        def _transform_bbox(self, trafo, bbox):
100          # This is not really the correct way to determine the bbox of a          # This is not really the correct way to determine the bbox of a
101          # projected shape, but for now it works well enough          # projected bbox, but for now it works well enough
102          llx, lly, urx, ury = bbox          llx, lly, urx, ury = bbox
103          xs = []; ys = []          xs = []; ys = []
104          x, y = self.Forward(llx, lly)          for x, y in ((llx, lly), (llx, ury), (urx, lly), (urx, ury)):
105          xs.append(x); ys.append(y)              x, y = trafo(x, y)
106          x, y = self.Forward(llx, ury)              xs.append(x); ys.append(y)
         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)  
           
107          return min(xs), min(ys), max(xs), max(ys)          return min(xs), min(ys), max(xs), max(ys)
108    
109        def ForwardBBox(self, bbox):
110            """Return the bounding box of the corners of the bounding box bbox
111            """
112            return self._transform_bbox(self.Forward, bbox)
113    
114        def InverseBBox(self, bbox):
115            return self._transform_bbox(self.Inverse, bbox)
116    
117      def GetName(self):      def GetName(self):
118          """Return the name of the projection."""          """Return the name of the projection."""
119          return self.name          return self.name
120    
121        def Label(self):
122            if self.epsg:
123                return "EPSG % 5s %s" % (self.epsg, self.name)
124            return self.name
125    
126        def EPSGCode(self):
127            """Return the EPSG code as a string or None if there is none"""
128            return self.epsg
129    
130      def GetParameter(self, param):      def GetParameter(self, param):
131          """Return the projection value for the given parameter.          """Return the projection value for the given parameter.
132    
133          If 'param' exists as a valid parameter then the returned          If 'param' exists as a valid parameter return the associated
134          value is a string with that value. If the parameter doesn't          value as a string. If the parameter does not have a value (like
135          exist an empty string is returned.          e.g. the 'south' parameter for utm) then the value is the
136            parameter name itself.
137    
138            If the parameter doesn't exist return an empty string.
139          """          """
140    
141          for pair in self.params:          for pair in self.params:
142              p, v = pair.split("=")              if "=" in pair:
143                    p, v = pair.split("=")
144                else:
145                    p = v = pair
146              if p == param:              if p == param:
147                  return v                  return v
148    
# Line 75  class Projection(BaseProjection): Line 152  class Projection(BaseProjection):
152          """Return list of 'parameter=value' strings"""          """Return list of 'parameter=value' strings"""
153          return self.params          return self.params
154    
155        def GetProjectedUnits(self):
156            if self.GetParameter("proj") in [ 'latlong', 'longlat' ]:
157                return PROJ_UNITS_DEGREES
158            else:
159                return PROJ_UNITS_METERS
160    
161      def __repr__(self):      def __repr__(self):
162          return self.name + ": " + repr(self.params)          return self.name + ": " + repr(self.params)
163    
164  class ProjFile:  
165    class ProjFile(Publisher):
166    
167      def __init__(self, filename):      def __init__(self, filename):
168          """Intialize the ProjFile.          """Intialize the ProjFile.
# Line 89  class ProjFile: Line 173  class ProjFile:
173          self.__projs = []          self.__projs = []
174    
175          self.SetFilename(filename)          self.SetFilename(filename)
       
     def Add(self, proj):  
         """Add the given projection to the end of the file. If 'proj'  
         already exists, it is replaced in the same location as the  
         original projection.  
         """  
176    
177          try:      def Add(self, proj):
178              #          """Add the projection to the end of the file."""
179              # see if the projection already exists.          self.__projs.append(proj)
180              # this only works if Projection doesn't override __eq__          self.issue(PROJECTION_ADDED, proj)
             #  
             self.__projs[self.__projs.index(proj)] = proj  
         except ValueError:  
             self.__projs.append(proj)  
181    
182      def Remove(self, proj):      def Remove(self, proj):
183          """Remove the object proj from the projection file.          """Remove the object proj from the projection file.
184    
185          Raises a ValueError is proj is not found.          Raises a ValueError is proj is not found.
186          """          """
   
187          self.__projs.remove(proj)          self.__projs.remove(proj)
188            self.issue(PROJECTION_REMOVED, proj)
189    
190      def Replace(self, oldproj, newproj):      def Replace(self, oldproj, newproj):
191          """Replace the object 'oldproj' with 'newproj'.          """Replace the object 'oldproj' with 'newproj'.
192            
193          Raises ValueError if oldproj is not in the file.          Raises ValueError if oldproj is not in the file.
194          """          """
   
         #  
         # see if the projection already exists.  
         # this only works if Projection doesn't override __eq__  
         #  
195          self.__projs[self.__projs.index(oldproj)] = newproj          self.__projs[self.__projs.index(oldproj)] = newproj
196            self.issue(PROJECTION_REPLACED, oldproj, newproj)
197    
198      def GetFilename(self):      def GetFilename(self):
199          """Return the filename where the ProjFile was read or will be          """Return the filename where the ProjFile was read or will be
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