Re: [Geotools-gt2-users] Getting Started with Point in Polygon

[Jody G. <jod...@gm...>]

Some good news; whatever platform you use you are going to end up coming 
down to the same code. The JTS Topology Suite point-in-polygon code is 
great; well tested etc.  If you did you work in QGIS you would end up 
using the GEOS implementation of this code (GEOS is a port of JTS to C++).

Here is some writing on the topic:
- 
http://lin-ear-th-inking.blogspot.com/2007/07/ultimate-point-in-polygon.html

Have a look here at the PointInRing classes:
- 
http://www.vividsolutions.com/Jts/javadoc/com/vividsolutions/jts/algorithm/package-summary.html

In GeoTools I would go through your polygons and build up an 
STRtreePointInRing for each one (keeping them in a 
Map<String,STRtreePointInRing>) and then go through your points; testing 
each point ...

Cheers,
Jody

Dave Everson wrote:
>
> Hello,
>
> I am very new to geocoding.  My experience to date has been using 
> algorithms to determine long/lat for an address and returning all 
> addresses within a radius around a zip code.
>
> I am now working with a youth sports organization that is dealing with 
> multiple city entities to allocate field space for participants.  We 
> are in the middle of a metropolitan area and the cities allocate field 
> usage based on the percentage of participants living within their city 
> limits. Zip code alone does not address this require because a zip 
> code may fall into multiple cities and/or school districts.
>
> We have all our participants geocoded with long/lat. We can get 
> shapefile from either our state government 
> (http://www.gis.leg.mn/html/download.html) or from TIGER. I have used 
> Quantam GIS to load the shapefile and then overlay with our 
> participants.  This looks cool, but we are dealing with 5000+ addresses.
>
> We would like to produce a report for our 5000+ addresses with the 
> city limits and school district they fall within.  This way we can 
> summarize the information for the city administrators we are dealing 
> with.
>
> I think the "point in polygon" algorithms is the approach we need to 
> take (could be wrong).  I have taken a look at some various APIs, but 
> have been left confused and uncertain about the direction to go.
> Can anyone provide some direction on how we can get started with using 
> the GeoTools API to load a shapefile form TIGER and then programically 
> determine the city of residence and school district for each participant?
>
> Thanks!
> Dave
>
>  
>
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