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# Copyright (c) 2001, 2002 by Intevation GmbH |
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# Authors: |
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# Bernhard Herzog <[email protected]> |
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# Jonathan Coles <[email protected]> |
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# |
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# This program is free software under the GPL (>=v2) |
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# Read the file COPYING coming with Thuban for details. |
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|
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__version__ = "$Revision$" |
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|
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import os |
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from math import log, ceil |
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|
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from Thuban import _ |
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|
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import shapelib, shptree |
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|
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from messages import LAYER_PROJECTION_CHANGED, LAYER_LEGEND_CHANGED, \ |
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LAYER_VISIBILITY_CHANGED |
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|
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from color import Color |
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|
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import classification |
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|
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from table import Table |
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|
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from base import TitledObject, Modifiable |
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|
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class Shape: |
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|
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"""Represent one shape""" |
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|
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def __init__(self, points): |
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self.points = points |
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#self.compute_bbox() |
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|
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def compute_bbox(self): |
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xs = [] |
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ys = [] |
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for x, y in self.points: |
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xs.append(x) |
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ys.append(y) |
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self.llx = min(xs) |
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self.lly = min(ys) |
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self.urx = max(xs) |
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self.ury = max(ys) |
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|
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def Points(self): |
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return self.points |
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|
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|
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|
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# Shape type constants |
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SHAPETYPE_POLYGON = "polygon" |
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SHAPETYPE_ARC = "arc" |
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SHAPETYPE_POINT = "point" |
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|
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# mapping from shapelib shapetype constants to our constants |
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shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON, |
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shapelib.SHPT_ARC: SHAPETYPE_ARC, |
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shapelib.SHPT_POINT: SHAPETYPE_POINT} |
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|
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shapetype_names = {SHAPETYPE_POINT: "Point", |
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SHAPETYPE_ARC: "Arc", |
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SHAPETYPE_POLYGON: "Polygon"} |
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|
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class BaseLayer(TitledObject, Modifiable): |
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|
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"""Base class for the layers.""" |
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|
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def __init__(self, title, visible = 1): |
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"""Initialize the layer. |
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|
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title -- the title |
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visible -- boolean. If true the layer is visible. |
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""" |
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TitledObject.__init__(self, title) |
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Modifiable.__init__(self) |
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self.visible = visible |
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|
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def Visible(self): |
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"""Return true if layer is visible""" |
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return self.visible |
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|
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def SetVisible(self, visible): |
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"""Set the layer's visibility.""" |
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self.visible = visible |
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self.issue(LAYER_VISIBILITY_CHANGED, self) |
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|
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|
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class Layer(BaseLayer): |
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"""Represent the information of one geodata file (currently a shapefile) |
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All children of the layer have the same type. |
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|
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A layer has fill and stroke colors. Colors should be instances of |
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Color. They can also be None, indicating no fill or no stroke. |
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|
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The layer objects send the following events, all of which have the |
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layer object as parameter: |
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|
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TITLE_CHANGED -- The title has changed. |
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LAYER_PROJECTION_CHANGED -- the projection has changed. |
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LAYER_LEGEND_CHANGED -- the fill or stroke attributes have changed |
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|
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""" |
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|
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def __init__(self, title, filename, projection = None, |
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fill = Color.None, |
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stroke = Color.Black, |
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stroke_width = 1, |
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visible = 1): |
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"""Initialize the layer. |
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|
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title -- the title |
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filename -- the name of the shapefile |
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projection -- the projection object. Its Inverse method is |
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assumed to map the layer's coordinates to lat/long |
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coordinates |
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fill -- the fill color or None if the shapes are not filled |
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stroke -- the stroke color or None if the shapes are not stroked |
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visible -- boolean. If true the layer is visible. |
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|
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colors are expected to be instances of Color class |
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""" |
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BaseLayer.__init__(self, title, visible = visible) |
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|
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# Make the filename absolute. The filename will be |
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# interpreted relative to that anyway, but when saving a |
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# session we need to compare absolute paths and it's usually |
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# safer to always work with absolute paths. |
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self.filename = os.path.abspath(filename) |
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|
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self.projection = projection |
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self.shapefile = None |
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self.shapetree = None |
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self.open_shapefile() |
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# shapetable is the table associated with the shapefile, while |
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# table is the default table used to look up attributes for |
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# display |
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self.shapetable = Table(filename) |
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self.table = self.shapetable |
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|
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self.__classification = classification.Classification(self) |
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self.__classification.SetDefaultStroke(stroke) |
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self.__classification.SetDefaultStrokeWidth(stroke_width) |
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self.__classification.SetDefaultFill(fill) |
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|
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self.UnsetModified() |
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|
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def open_shapefile(self): |
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if self.shapefile is None: |
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self.shapefile = shapelib.ShapeFile(self.filename) |
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numshapes, shapetype, mins, maxs = self.shapefile.info() |
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self.numshapes = numshapes |
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self.shapetype = shapelib_shapetypes[shapetype] |
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|
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# if there are shapes, set the bbox accordinly. Otherwise |
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# set it to None. |
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if self.numshapes: |
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self.bbox = mins[:2] + maxs[:2] |
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else: |
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self.bbox = None |
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|
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# estimate a good depth for the quad tree. Each depth |
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# multiplies the number of nodes by four, therefore we |
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# basically take the base 4 logarithm of the number of |
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# shapes. |
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if self.numshapes < 4: |
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maxdepth = 1 |
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else: |
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maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4))) |
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|
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self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2, |
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maxdepth) |
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|
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def Destroy(self): |
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BaseLayer.Destroy(self) |
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if self.shapefile is not None: |
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self.shapefile.close() |
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self.shapefile = None |
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self.shapetree = None |
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self.table.Destroy() |
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|
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def BoundingBox(self): |
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"""Return the layer's bounding box in the intrinsic coordinate system. |
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If the layer has no shapes, return None. |
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""" |
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# The bbox will be set by open_shapefile just as we need it |
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# here. |
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self.open_shapefile() |
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return self.bbox |
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|
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def LatLongBoundingBox(self): |
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"""Return the layer's bounding box in lat/long coordinates. |
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Return None, if the layer doesn't contain any shapes. |
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""" |
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bbox = self.BoundingBox() |
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if bbox is not None: |
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llx, lly, urx, ury = bbox |
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if self.projection is not None: |
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llx, lly = self.projection.Inverse(llx, lly) |
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urx, ury = self.projection.Inverse(urx, ury) |
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return llx, lly, urx, ury |
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else: |
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return None |
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|
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def NumShapes(self): |
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"""Return the number of shapes in the layer""" |
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self.open_shapefile() |
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return self.numshapes |
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|
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def ShapeType(self): |
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"""Return the type of the shapes in the layer. |
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This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON. |
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""" |
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self.open_shapefile() |
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return self.shapetype |
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|
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def Shape(self, index): |
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"""Return the shape with index index""" |
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self.open_shapefile() |
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shape = self.shapefile.read_object(index) |
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|
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if self.shapetype == SHAPETYPE_POINT: |
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points = shape.vertices() |
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else: |
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#for poly in shape.vertices(): |
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poly = shape.vertices()[0] |
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points = [] |
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for x, y in poly: |
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points.append((x, y)) |
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return Shape(points) |
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|
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def ShapesInRegion(self, box): |
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"""Return the ids of the shapes that overlap the box. |
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Box is a tuple (left, bottom, right, top) in the coordinate |
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system used by the layer's shapefile. |
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""" |
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left, bottom, right, top = box |
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return self.shapetree.find_shapes((left, bottom), (right, top)) |
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|
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def SetProjection(self, projection): |
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"""Set the layer's projection""" |
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self.projection = projection |
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self.changed(LAYER_PROJECTION_CHANGED, self) |
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|
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def GetClassification(self): |
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return self.__classification |
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|
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def SetClassification(self, clazz): |
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self.__classification = clazz |
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self.changed(LAYER_LEGEND_CHANGED, self) |
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|
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def TreeInfo(self): |
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items = [] |
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|
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if self.Visible(): |
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items.append(_("Shown")) |
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else: |
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items.append(_("Hidden")) |
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items.append(_("Shapes: %d") % self.NumShapes()) |
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|
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bbox = self.LatLongBoundingBox() |
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if bbox is not None: |
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items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox) |
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else: |
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items.append(_("Extent (lat-lon):")) |
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items.append(_("Shapetype: %s") % shapetype_names[self.ShapeType()]) |
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|
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items.append(self.__classification) |
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|
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return (_("Layer '%s'") % self.Title(), items) |
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