[postgis-users] Expand odd shapes

[Andy Colson]

Hi all.

I have buffer selection problem.  My site can drop a point, then find 
all the parcels within 100 feet of that point.  No problem.

One client however would like to select a parcel (maybe its a square, 
maybe its a triangle, or any other odd shape), and find all other 
parcels within 100 feet of any point within the source parcel.

100 is optional.  They could choose 50, or 150.

I'm not sure how to do something like this.  I found ST_Expand, but 
that'll create a bounding box around the triangle.

ST_TransScale could scale it, but I'm not sure what the scale is.  The 
user might type in 50 feet or 150 feet, I'm not sure how to calculate a 
deltaX and deltaY scale for that.

Any hints on how I might go about this?  I'm a bit stuck.

Thanks,

-Andy