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

[Daniel Morissette]

Kevin Flanders wrote:
> 
> Is there a way of exploiting this functionality to create an abutter's list
> function for municipal applications?  If we can create a new shape that
> mimics an existing/selected parcel, then can't we use that shape like we
> would a user-defined query rectangle to intersect parcel features?
> 
> I know there has been talk about abutters list before, but it doesn't seem
> like there has been any resolution....
> 


If I understand well, the idea is to select all parcels that are
adjacent to a selected parcel.  It may not be possible to use
QueryByShape for this because it looks for shapes that intersect or are
located inside the shape you use for the query... so non-intersecting
neighbors won't be selected.

The best would be if we could create a new shape that is the parcel of
interest with a buffer added around it and use that buffered parcel in a
queryByShape().  Unfortunately for you there is no way to create such a
vector buffer in MapServer.

Another trick could be to sample points every few meters along the
border of the parcel of interest and do a point query at every step with
a tolerance of half the distance between the sampled points.  You would
compile a list of the returned parcel ids as you walk around the parcel
and this would give you your list of abutters.

I'll CC: to the list where others may have better suggestions.

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