[Shapelib] Verifying shapefile contents

Eron Lloyd eronlloyd at gmail.com
Wed Aug 30 12:26:27 EDT 2006


I'm doing some prelimenary analysis for a land value tax in Reading, PA, and 
am currently reviewing the property assessment rolls. Unfortunately, like 
many voter lists, I've discovered hundreds of records with invalid data; in 
this case, many records aren't listed as being part of the municipality but 
are, or even the reverse, where land outside the city's border is listed as 
part of the city. I have the city's shapefile, which provides all the parcel 
data, and I was wondering if it would be possible to use shapelib to

1. process the entire list of map pins (each a unique # that identifies a 
parcel in the shapefile, such as 530764436089)

2. verify that each parcel is within the city's taxable jurisdiction (i.e. 
boundary lines) or not (even testing for partial inclusion)

3. manipulate the shapefile to represent visually any invalid, 
unaccounted-for, or otherwise incorrectly designated parcels

I assume the GIS dept. could perhaps help with this, but developing a personal 
tool to do this would be useful and educational. My language of choice is 
Python, and I'd be happy to share the code once I get it working. My basic 
need is a guide to the API and suggestions for how to proceed. I can 
translate the procedure calls into Python.


Eron Lloyd

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