point within polygon

[Dylan Beaudette]

Thanks Steve, this was exactly what I was looking for.

Next question in a new thread...

Cheers,

Dylan


On Monday 22 August 2005 12:41 pm, Steve Lime wrote:
> MapServer has that capability within MapScript. shapeObj's have a contains
> method that will tell you if a point is contained in a polygon. E.g.:
>
>   $status = $polygon->contains($point);
>
> The behaviour of the MapServer point-in-polygon algorithm is indeterminent
> if the point lies exactly on the edge of the polygon. The return value is
> consistent though. I guess the point is that contains really means
> contains.
>
> Steve
>
> >>> Dylan Beaudette <dylan at IICI.NO-IP.ORG> 08/22/05 1:59 PM >>>
>
> Greetings,
>
> I am currently looking for a way to test if a point is within a polygon,
> without using PostGIS. The first method I have tried, and which works but
> not well, is with a simple comparison within MySQL:
>
> point at x,y
>
> polygon extent: min_x,min_y,max_x,max_y
>
> if x >= min_x and x <= max_x and y >= min_y and y <= max_y then OK
>
> however, most of my polygons are not rectangular, and thus many point may
> seemingly be in multiple polygons when rectangular extents overlap...
>
> is there a better way to do this within mapserver, or phpmapscript?
>
> or is there a postGIS-like patch for MySQL ?
>
> thanks in advance!

-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341