[OpenMap Users] Custom shp/dbf handling

From: Brian M Dube <brian.dube_at_gmail.com>
Date: Sun, 23 Aug 2009 14:04:55 -0700

Greetings,

I see in the OpenMap FAQ that a generic system to handle the
associations between a shape file and its attribute table has not been
implemented. I'm working on a custom implementation, and I'm stuck.

I'm working with r2054 from the svn repository. One of the shape files
I want to use is a Census TIGER/Line file that describes all edges at
the county level (roads, water features, railways, etc.) and is quite
a large file. I was running out of heap space in
DbfInputStream.readData() because of the size of the file, and
readData() is called directly from DbfInputStream.<init> (the constructor).

So I copied DbfInputStream to my project and, with some modifications,
made a small tool to populate HSQLDB tables with the records in the
dbf file passed to the tool. This worked really well.

This is where I'm stuck. I don't know which OpenMap component to
customize to use the attributes that are now in the HSQLDB tables. Is
it ShapeLayer? or a new DbfHandler that reads from the database?

The goal is to use SQL queries on the attribute table to limit what
geometry is drawn from the shape file. Highways and streets, for
example.

Thanks,
Brian

-- 
Brian M. Dube
Aircraft Owners and Pilots Association, Member 05135381
Experimental Aircraft Association, Member 1002851
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Received on Sun Aug 23 2009 - 17:07:24 EDT

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