method lets you juggle both the
geometry and dbf attributes at the
Here’s a simple usage example followed by a detailed explanation and a few other posts where I use this method without much explanation.
Let’s say you have a simple point-location address shapefile named “addr.shp” with the following structure:
|[-89.522996, 34.363596]||7018 South 8th||Oxford||MS||38655|
|[-89.520695, 34.360863]||1199 South 11th||Oxford||MS||38655|
|[-89.520927, 34.362924]||8005 Fillmore Ave||Oxford||MS||38655|
You could then use the shapeRecords method like this:
>>> import shapefile >>> r = shapefile.Reader(“addr”) >>> sr = r.shapeRecords() >>> # get the first shaperecord >>> sr_test = sr >>> # Look at the geometry of the shape >>> sr_test.shape.points [[-89.522996, 34.363596]] >>> # Look at the attributes of the dbf record >>> sr_test.record [‘7018 South 8’,’Oxford’,’MS’,’38655’] >>> # Now let’s iterate through all of them >>> for sr in r.shapeRecords(): ... print “x: “, sr.points ... print “y: “, sr.points ... # Output just the address field ... print “Address: “, sr.record x: -89.522996 y: 34.363596 Address: 7018 South 8th x: -89.520695 y: 34.360863 Address: 1195 South 11th x: -89.520927 y: 34.362924 Address: 805 Fillmore Ave
Here’s how it works.
The shapeRecords() method returns a list.
Each entry in that list is a _ShapeRecord object instance.
A _ShapeRecord object has two attributes: shape, record
_ShapeRecord.record contains a simple list of the attributes.
_ShapeRecord.shape contains a _Shape object instance.
A _Shape object has, at a minimum, two attributes: shapeType, points
If the _Shape instance contains a polygon a “parts” attribute will appear. This attribute contains the index in the point list of the beginning of a “part”. Parts let you store multiple shapes in a single record.
The shapeType attribute provides a number telling you if the shapefile is a point, polygon, line, etc. file. These constants are listed in the shapefile spec document as well as near the top of the source code.
The points is just a list containing lists of the point coordinates. Two things to note: If the geometry has multiple parts, such as multiple polygons, the points for all parts are just lumped together. You must separate them by referencing the parts index list. Some shape types allow for z and m values which may appear in addition to the x,y pairs.
This method is really just a clumsy convenience method that basically zips up the results of the shapes() and records() methods you are already using.
I have a few blog posts where I call this method as well:
http://geospatialpython.com/2010/12/dot-density-maps-with-python-and-ogr.html (in the comments)