/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/resource.py
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revision 1161 by jonathan, Thu Jun 12 12:41:01 2003 UTC revision 1816 by bh, Mon Oct 13 15:53:56 2003 UTC
# Line 5  Line 5 
5  # This program is free software under the GPL (>=v2)  # This program is free software under the GPL (>=v2)
6  # Read the file COPYING coming with Thuban for details.  # Read the file COPYING coming with Thuban for details.
7    
8    """Handle resources loaded from files such as projections"""
9    
10    __version__ = "$Revision$"
11    # $Source$
12    # $Id$
13    
14    
15  import os  import os
16  import os.path  import os.path
17    
# Line 21  from xml.sax import SAXParseException Line 28  from xml.sax import SAXParseException
28  projdir = \  projdir = \
29          os.path.join(Thuban.__path__[0], os.pardir, "Resources", "Projections")          os.path.join(Thuban.__path__[0], os.pardir, "Resources", "Projections")
30    
 usrdir  = get_application_dir()  
31    
32  PROJ_EXT = ".proj"  PROJ_EXT = ".proj"
33    
34  has_gdal_support = lambda: False  has_gdal_support = lambda: False
35  try:  try:
36        # first try to see if our extension module is there. if it
37        # wasn't even compiled, we obviously don't have gdal support.
38        import gdalwarp
39    
40        # now try to import the python extension. if this doesn't
41        # exist then we can't do anything.
42      import gdal      import gdal
43    
44      """Return True if the gdal library is available."""      """Return True if the gdal library is available."""
45      has_gdal_support = lambda: True      has_gdal_support = lambda: True
46  except ImportError:  except ImportError:
47      pass      pass
48    
49  def read_proj_file(filename):  def read_proj_file(filename):
50      """Read a single .proj file and return a ProjFile object.      """Read a .proj file and return a ProjFile object and warnings
51        
52      Raises IOError if the file cannot be opened.      The return value is a tuple with the ProjFile object and a list of
53      Raises OSError if the file cannot be read.      strings with warnings messages that might have been generated by the
54      Raises SAXParseException if the file is not valid XML.      proj ifle parser.
     """  
55    
56        Raises IOError if the file cannot be opened, OSError if the file
57        cannot be read and SAXParseException if the file is not valid XML.
58        """
59      handler = ProjFileReader()      handler = ProjFileReader()
60      handler.read(filename)      handler.read(filename)
61      return handler.GetProjFile()      return handler.GetProjFile(), handler.GetWarnings()
62    
63  def write_proj_file(pf):  def write_proj_file(pf):
64      """Write a single .proj file      """Write a single .proj file
# Line 54  def write_proj_file(pf): Line 69  def write_proj_file(pf):
69      saver = ProjFileSaver(pf)      saver = ProjFileSaver(pf)
70      saver.write(pf.GetFilename())      saver.write(pf.GetFilename())
71    
 def get_proj_files(dir):  
     """Read all .proj files in the given directory and  
     return a list of ProjFile objects.  
     """  
72    
73      list = []  def get_system_proj_file():
74      try:      """Return the standard projections and a list with warnings
75          dirlist = os.listdir(dir)  
76      except OSError:      The projections read from the default thuban projection file
77          pass # if we can't get a directory listing just return []      (usually in Resources/Projections/defaults.proj). The return value
78      else:      is a tuple with the projections in a ProjFile object and a list of
79          for file in filter(lambda s: s.endswith(PROJ_EXT), dirlist):      strings with warning messages. The warnings list is usually empty
80              try:      but may contain messages about ignored errors.
                 filename = os.path.join(dir, file)  
                 list.append(ReadProjFile(filename))  
             except (OSError, IOError, SAXParseException):  
                 pass # just move onto the next file  
   
     return list  
   
 def get_system_proj_files():  
     """Return a list of ProjFile objects from files that are  
     supplied by Thuban.  
81    
82      If no files could not be opened return a list with one      If the file could could not be opened return an empty projection
83      empty projection file set to store data in the default file.      file object set to store data in the default file.
84      """      """
85      filename = os.path.join(projdir, "defaults.proj")      filename = os.path.join(projdir, "defaults.proj")
86      try:      try:
87          return [ReadProjFile(filename)]          return read_proj_file(filename)
88      except (OSError, IOError, SAXParseException):      except (OSError, IOError, SAXParseException), val:
89          return [ProjFile(filename)]          msg = _('Could not read "%s": %s') % (filename, str(val))
90            return ProjFile(filename), [msg]
91  def get_user_proj_files():  
92      """Return a list of ProjFile objects from files that are user-defined.  def get_user_proj_file():
93        """Return the user's projections and a list with warnings
94    
95        The projections read from the user's thuban projection file (usually
96        in ~/.thuban/user.proj). The return value is a tuple with the
97        projections in a ProjFile object and a list of strings with warning
98        messages. The warnings list is usually empty but may contain
99        messages about ignored errors.
100    
101      If no files could not be opened return a list with one      If the file could could not be opened return an empty projection
102      empty projection file set to store data in the default file.      file object set to store data in the default file.
103      """      """
104        usrdir  = get_application_dir()
105      filename = os.path.join(usrdir, "user.proj")      filename = os.path.join(usrdir, "user.proj")
106      try:      try:
107          return [ReadProjFile(filename)]          return read_proj_file(filename)
108      except (OSError, IOError, SAXParseException):      except (OSError, IOError, SAXParseException), val:
109          return [ProjFile(filename)]          msg = _('Could not read "%s": %s') % (filename, str(val))
110            return ProjFile(filename), [msg]
111    
112    
113  class ProjFileReader(XMLReader):  class ProjFileReader(XMLReader):
114    
115      def __init__(self):      def __init__(self):
116          XMLReader.__init__(self)          XMLReader.__init__(self)
117          self.__pf = ProjFile("")          self.projfile = ProjFile("")
118            self.warnings = []
119    
120          XMLReader.AddDispatchers(self,          XMLReader.AddDispatchers(self,
121              {'projection': ("start_projection", "end_projection"),              {'projection': ("start_projection", "end_projection"),
122               'parameter':  ("start_parameter", None)})               'parameter':  ("start_parameter", None)})
123                
124      def read(self, file_or_filename):      def read(self, file_or_filename):
125          XMLReader.read(self, file_or_filename)          XMLReader.read(self, file_or_filename)
126    
127          self.__pf.SetFilename(XMLReader.GetFilename(self))          self.projfile.SetFilename(XMLReader.GetFilename(self))
128            
129      def start_projection(self, name, qname, attrs):      def start_projection(self, name, qname, attrs):
130          self.params = []          self.params = []
131          self.name = self.encode(attrs.get((None, 'name'), _("Unknown")))          name = self.encode(attrs.get((None, 'name')))
132            if name is None:
133                name = _("Unknown")
134            self.name = name
135            self.epsg = self.encode(attrs.get((None, 'epsg')))
136    
137      def end_projection(self, name, qname):      def end_projection(self, name, qname):
138          self.__pf.Add(Projection(self.params, self.name))          try:
139                proj = Projection(self.params, self.name, epsg = self.epsg)
140            except IOError, val:
141                self.warnings.append(_('Error in projection "%s": %s')
142                                     % (self.name, str(val)))
143            else:
144                self.projfile.Add(proj)
145    
146      def start_parameter(self, name, qname, attrs):      def start_parameter(self, name, qname, attrs):
147          s = attrs.get((None, 'value'))          s = attrs.get((None, 'value'))
# Line 128  class ProjFileReader(XMLReader): Line 149  class ProjFileReader(XMLReader):
149          self.params.append(s)          self.params.append(s)
150    
151      def GetProjFile(self):      def GetProjFile(self):
152          return self.__pf          return self.projfile
153    
154        def GetWarnings(self):
155            """Return the list of warning messages that may have been produced"""
156            return self.warnings
157    
158    
159  class ProjFileSaver(XMLWriter):  class ProjFileSaver(XMLWriter):
160    
# Line 139  class ProjFileSaver(XMLWriter): Line 165  class ProjFileSaver(XMLWriter):
165      def write(self, file_or_filename):      def write(self, file_or_filename):
166          XMLWriter.write(self, file_or_filename)          XMLWriter.write(self, file_or_filename)
167    
168          self.write_header("projfile", "projfile.dtd")          self.write_header("projectionlist", "projfile.dtd")
169          self.write_projfile(self.__pf)          self.write_projfile(self.__pf)
170          self.close()          self.close()
171    
# Line 148  class ProjFileSaver(XMLWriter): Line 174  class ProjFileSaver(XMLWriter):
174          self.open_element("projectionlist")          self.open_element("projectionlist")
175    
176          for p in pf.GetProjections():          for p in pf.GetProjections():
177              self.open_element("projection", {"name": p.GetName()})              attrs = {"name": p.GetName()}
178                if p.EPSGCode():
179                    attrs["epsg"] = p.EPSGCode()
180                self.open_element("projection", attrs)
181    
182              for param in p.GetAllParameters():              for param in p.GetAllParameters():
183                  self.write_element("parameter", {"value": param})                  self.write_element("parameter", {"value": param})
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