[postgis-users] trace back

[Andy Colson]

> On 2/19/2013 12:35 PM, Jonatan Malaver wrote:
>> Hello,
>>
>>     Let's say I have 3 parcel centroids with one feature in common. How
>> would I do a trace back to the common feature between those points?
>> Also, how can I do a flood analysis?
>>
>> Thanks,
>>
>> Jonatan Malaver
>>
>> Assistant Engineer of Electrical and Cable Operations
>>
>> Shrewsbury Electric & Cable Operations
>>
>> 100 Maple Avenue
>>
>> Shrewsbury, MA 01545
>>
>> Office: 508.841.1520
>>
>> Mobile: 774.262.0437
>>
>> Fax: 508.842.9267
>>
>> jon.malaver at shrewsburyma.gov <mailto:jon.malaver at shrewsburyma.gov>
>>
>>
>>
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>>
>
>
> That's pretty vague.  So you have parcel points, and not polygons?  In a table called ParcelPoints?
>
> What is this feature?  Is it a column in table ParcelPoints?  Or is it a point in a different table?  Is it a polygon?  Is it in a table or are you hard coding it in wkt?  (like "POINT(42 42)")
>
> -Andy
>

On 2/19/2013 1:12 PM, Jonatan Malaver wrote:> Let me give you more info. 
I'm trying to sync my GIS with our outage management system (small 
electric utility). I would like to trace back an outage call (customer 
points) to a common transformer (point), fuse (point), or station 
(point). All the points are in different tables, and they are all 
intersected by a line (circuit).
 >
 > Thanks,
 >
 > Jonatan Malaver
 > Assistant Engineer of Electrical and Cable Operations
 > Shrewsbury Electric & Cable Operations
 > 100 Maple Avenue
 > Shrewsbury, MA 01545
 > Office: 508.841.1520
 > Mobile: 774.262.0437
 > Fax: 508.842.9267
 > jon.malaver at shrewsburyma.gov
 >
 > -----Original Message-----
 > From: Andy Colson [mailto:andy at squeakycode.net]
 > Sent: Tuesday, February 19, 2013 2:04 PM
 > To: PostGIS Users Discussion
 > Cc: Jonatan Malaver
 > Subject: Re: [postgis-users] trace back
 >


Hum...  As a test, can you do something like:

select *
from circuit
inner join station on ST_Intersects(circut.geom, station.geom)
where circuit.id = 42;

The id = 42 is meant to only pull back one line of the circuit, and the 
join is to see if it'll match all the stations on that line.


-Andy