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

[Ed McNierney]

Folks -

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.

Unfortunately, the standard for such applications is pretty high.  Accidentally omitting people from a list used for sending out legal notices can be a nightmare for the municipality, so the answers need to be quite accurate, and not "close enough".

Steve, you need to get out East more often <g>.  Parcels outside of the Public Land Survey System states are anything BUT regular in shape!

Buffering seems to be the only way to go.....

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 

-----Original Message-----
From: Lowell Filak [mailto:lfilak at medinaco.org]
Sent: Tuesday, November 19, 2002 11:52 AM
To: Daniel Morissette; kevin at peoplegis.com
Cc: mapserver-users
Subject: Re: [mapserver-users] Creating an abutter's list (was:
Accessing Vertices of a Shape - PHP MapScript)


That's the best idea/work-a-round I've heard yet.
Lowell F.

The following message was sent by Daniel Morissette <morissette at dmsolutions.ca> on Tue, 19 Nov 2002 10:19:51 -0500.

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