[mapserver-users] Creating an abutter's list (was: Accessing Vertices of a Shape - PHP MapScript)

[Daniel Morissette]

Ed McNierney wrote:
> 
> Daniel's proposal is for ADJACENT parcels, which tend to not be what's required in municipal applications.  The typical "abutters list" requires all parcels that have any point within them lying within some distance (say, 300 feet) of any point within the subject parcel.  In densely subdivided areas, this may include parcels that are several parcels away from the subject parcel.
> 

Agreed that real buffering is the best solution.  Steve's suggestion to
honor the tolerance with the shape query would work too.

As an interim solution, you could set the tolerance to 300 feet and then
do your query using MS_MULTIPLE (in MapScript) and it will return you
any parcel within 300 feet.  You would still have to walk along the edge
of the parcel of interest with a fairly small step value (a few feet
max), and you should calculate a search tolerance (a little over 300
feet) to match the step value and make sure you catch *any* polygon
within 300 feet.

I agree that this would still return an approximation, but you should
not miss any parcel if your step and search radius are set properly.  In
the worst cases you may end up with extra parcels that you would have to
filter out.

Daniel
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 Daniel Morissette               morissette at dmsolutions.ca
 DM Solutions Group              http://www.dmsolutions.ca/
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