CGL - Computational Geography Library

This is a library that consolidates and extends the Python programs developed for the GIS Algorithms book.

Installation

Right now the package can be installed using the setup.py file.

python3 setup.py install

Coming soon: pip install

Usage

There are many uses of the library. Here are examples of using the k-D trees:

>>> from cgl.kdtree import *
>>> from cgl.point import Point
>>> data1 = [ (2,2), (0,5), (8,0), (9,8), (7,14), (13,12), (14,13) ]
>>> points = [Point(d[0], d[1]) for d in data1]
>>> tree = kdtree(points)
>>> print([tree.query_kdtree(p)[0] for p in points])
[(0, 5), (2, 2), (7, 14), (8, 0), (9, 8), (13, 12), (14, 13)]
>>> print('Depth of tree:', tree.depth())
Depth of tree: 2
>>> rect = [ [1, 9], [2, 9] ]
>>> found = tree.range_query_orthogonal(rect)
>>> print(found)
[(2, 2), (9, 8)]
>>> tree.draw()
       ____(8, 0)____         
      /              \        
   (0, 5)         (13, 12)    
   /     \        /      \    
(2, 2) (7, 14) (9, 8) (14, 13)
/    \ /     \ /    \ /      \

Here are examples of using shapex in the util folder (assuming running from the folder where the shapefile is stored):

>>> from cgl.kdtree import *
>>> from cgl.point import Point
>>> from cgl.util.shapex import *
>>> fname = 'uscnty48area.shp'
>>> shp = shapex(fname)
>>> shp
<cgl.util.shapex.shapex object at 0x103d86240>
>>> shp.bounds
(-124.73277020117189, 24.956375330360743, -66.96927114737537, 49.37173035309934)
>>> shp.schema
{'geometry': 'Polygon', 'properties': [('NAME', 'str:32'), ('STATE_NAME', 'str:25'), ('FIPS', 'str:5'), ('UrbanPop', 'float:19.11'), ('Area', 'float:19.10'), ('AreaKM2', 'float:19.10'), ('GEO_ID', 'str:50'), ('PopDensity', 'int:15')]}
>>> len(shp)
3109
>>> feature = shp[10]
>>> feature['properties']
{'NAME': 'Josephine', 'STATE_NAME': 'Oregon', 'FIPS': '41033', 'UrbanPop': 51.68106067, 'Area': 4252338287.86, 'AreaKM2': 4252.33828786, 'GEO_ID': '05000US41033', 'PopDensity': 17}
>>> feature['geometry']['type']
'Polygon'