/[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 2698 by bernhard, Mon Sep 18 00:56:26 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            locale.setlocale(locale.LC_NUMERIC, savedlocale)
39            if result1 != result2:
40                return True
41        return False
42    
43  class Projection(BaseProjection):  class Projection(BaseProjection):
44        """A proj4 projection object that remembers the parameters.
45    
46        Note: it seems that calling
47            self.assuregoodlocale()
48            self.assureinitlocale()
49        before BaseProjection.__init__() is enough to work around the bug.
50    
51      """A proj4 projection object that remembers the parameters"""      We assuming that the locale stays the same after a projection
52        has been initialised
53        and thus we can return to it in self.assureinitlocale().
54        """
55    
56      def __init__(self, params, name = None):      def __init__(self, params, name = None, epsg = None):
57          """Initialize the Projection with a list of          """Initialize the Projection
58          'parameter=value' strings and an optional name. If 'name' is  
59          None, the name will be set to 'Unknown' in the local language.          Parameters:
60    
61            params -- a list of 'parameter=value' strings
62    
63            name -- (optional) The name of the projection. If None or omitted
64                    it defaults to 'Unknown' in the local language.
65    
66            epsg -- (optional) The EPSG code as a string.
67          """          """
68            self.initlocale = locale.getlocale(locale.LC_NUMERIC)
69            self.work_around_broken_proj = _do_we_have_to_work_around_broken_proj()
70    
71            self.assuregoodlocale()
72          BaseProjection.__init__(self, params)          BaseProjection.__init__(self, params)
73            self.assureinitlocale()
74    
75          if name is None:          if name is None:
76              self.name = _("Unknown")              self.name = _("Unknown")
77          elif isinstance(name, StringTypes):          elif isinstance(name, StringTypes):
78              self.name = name              self.name = name
79    
80            self.epsg = epsg
81          self.params = params          self.params = params
82    
83      def ForwardBBox(self, bbox):      def assuregoodlocale(self):
84          """Return the bounding box of the corners of the bounding box bbox          if self.work_around_broken_proj:
85          """              locale.setlocale(locale.LC_NUMERIC, "C")
86    
87        def assureinitlocale(self):
88            if self.work_around_broken_proj:
89                locale.setlocale(locale.LC_NUMERIC, self.initlocale)
90    
91        def _transform_bbox(self, trafo, bbox):
92          # 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
93          # projected shape, but for now it works well enough          # projected bbox, but for now it works well enough
94          llx, lly, urx, ury = bbox          llx, lly, urx, ury = bbox
95          xs = []; ys = []          xs = []; ys = []
96          x, y = self.Forward(llx, lly)          for x, y in ((llx, lly), (llx, ury), (urx, lly), (urx, ury)):
97          xs.append(x); ys.append(y)              x, y = trafo(x, y)
98          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)  
           
99          return min(xs), min(ys), max(xs), max(ys)          return min(xs), min(ys), max(xs), max(ys)
100    
101        def ForwardBBox(self, bbox):
102            """Return the bounding box of the corners of the bounding box bbox
103            """
104            return self._transform_bbox(self.Forward, bbox)
105    
106        def InverseBBox(self, bbox):
107            return self._transform_bbox(self.Inverse, bbox)
108    
109      def GetName(self):      def GetName(self):
110          """Return the name of the projection."""          """Return the name of the projection."""
111          return self.name          return self.name
112    
113        def Label(self):
114            if self.epsg:
115                return "EPSG % 5s %s" % (self.epsg, self.name)
116            return self.name
117    
118        def EPSGCode(self):
119            """Return the EPSG code as a string or None if there is none"""
120            return self.epsg
121    
122      def GetParameter(self, param):      def GetParameter(self, param):
123          """Return the projection value for the given parameter.          """Return the projection value for the given parameter.
124    
125          If 'param' exists as a valid parameter then the returned          If 'param' exists as a valid parameter return the associated
126          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
127          exist an empty string is returned.          e.g. the 'south' parameter for utm) then the value is the
128            parameter name itself.
129    
130            If the parameter doesn't exist return an empty string.
131          """          """
132    
133          for pair in self.params:          for pair in self.params:
134              p, v = pair.split("=")              if "=" in pair:
135                    p, v = pair.split("=")
136                else:
137                    p = v = pair
138              if p == param:              if p == param:
139                  return v                  return v
140    
# Line 75  class Projection(BaseProjection): Line 144  class Projection(BaseProjection):
144          """Return list of 'parameter=value' strings"""          """Return list of 'parameter=value' strings"""
145          return self.params          return self.params
146    
147        def GetProjectedUnits(self):
148            if self.GetParameter("proj") in [ 'latlong', 'longlat' ]:
149                return PROJ_UNITS_DEGREES
150            else:
151                return PROJ_UNITS_METERS
152    
153      def __repr__(self):      def __repr__(self):
154          return self.name + ": " + repr(self.params)          return self.name + ": " + repr(self.params)
155    
156  class ProjFile:  
157    class ProjFile(Publisher):
158    
159      def __init__(self, filename):      def __init__(self, filename):
160          """Intialize the ProjFile.          """Intialize the ProjFile.
# Line 89  class ProjFile: Line 165  class ProjFile:
165          self.__projs = []          self.__projs = []
166    
167          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.  
         """  
168    
169          try:      def Add(self, proj):
170              #          """Add the projection to the end of the file."""
171              # see if the projection already exists.          self.__projs.append(proj)
172              # 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)  
173    
174      def Remove(self, proj):      def Remove(self, proj):
175          """Remove the object proj from the projection file.          """Remove the object proj from the projection file.
176    
177          Raises a ValueError is proj is not found.          Raises a ValueError is proj is not found.
178          """          """
   
179          self.__projs.remove(proj)          self.__projs.remove(proj)
180            self.issue(PROJECTION_REMOVED, proj)
181    
182      def Replace(self, oldproj, newproj):      def Replace(self, oldproj, newproj):
183          """Replace the object 'oldproj' with 'newproj'.          """Replace the object 'oldproj' with 'newproj'.
184            
185          Raises ValueError if oldproj is not in the file.          Raises ValueError if oldproj is not in the file.
186          """          """
   
         #  
         # see if the projection already exists.  
         # this only works if Projection doesn't override __eq__  
         #  
187          self.__projs[self.__projs.index(oldproj)] = newproj          self.__projs[self.__projs.index(oldproj)] = newproj
188            self.issue(PROJECTION_REPLACED, oldproj, newproj)
189    
190      def GetFilename(self):      def GetFilename(self):
191          """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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