Mark,
> I've had a go at this using constraints and plpgsql, which seems more
> intuitive to me:
>
> alter table rbasin_point add constraint contained_within_basin CHECK
> (assertContains(the_geom, 'containing_table', 'containing_geom_column'));
Not a big expert on PostgreSQL but this (being able
I've had a go at this using constraints and plpgsql, which seems more
intuitive to me:
alter table rbasin_point add constraint contained_within_basin CHECK
(assertContains(the_geom, 'containing_table', 'containing_geom_column'));
Where assertContains is:
CREATE OR REPLACE FUNCTION assertContains
Joao,
There is no spatial declarative referential integrity in PostgreSQL/PostGIS
through which what you want to do can be done.
SQL92 Assertions goes closest to what you want to do. For example:
CREATE ASSERTION building_is_within_parcel
CHECK (EXISTS (SELECT 1
FROM parcel p,
building b
Hi Blake,
I have done this sort of thing pretty often... I find PostGIS makes it pretty
easy.
My approach is to generate an arbitrary equal area projection which reasonably
robustly covers the area of interest. (Let me know if you need a hand with this)
The buffering query then transforms the
Bruce,
Ok thanks.. that explains a lot. So really my only course of action is
to transform to UTM, do my buffer, then transform back to WGS84?
Blake
Bruce Rindahl wrote:
A nautical mile is 1 minute measured along a great circle on a sphere
(such as the equator or a longitude line). Thus you
>From Wikipedia http://en.wikipedia.org/wiki/Nautical_mile
A nautical mile or sea mile is a unit of length. It corresponds
approximately to one minute of latitude along any meridian. It is a
non-SI unit used especially by navigators in the shipping and
aviation industries.[1] It is
Nautical miles are roughly based on 1 minute of longitude, but that only
equals (approximately) one minute of latitude at the equator, so you won't
really have a 2NM radius circle if you use WSG84. You should probably use a
meter-based projection and create the circle based on a nautical mile being
A nautical mile is 1 minute measured along a great circle on a sphere
(such as the equator or a longitude line). Thus your query will not
work- it will be too short in the x direction. If you are using UTM a
nautical mile is about 1852 meters.
Bruce
Blake Crosby wrote:
I'm trying to create
Kevin,
This query works like a champ. Thank you very much for your help!
Doug
On Sep 11, 2008, at 2:49 PM, Kevin Neufeld wrote:
Ok, yikes. This is suddenly getting much more complicated than I
originally thought.
Yes, obviously the boundary approach does not take into account if
the po
I'm trying to create "circles" by using the buffer function around a point.
The radius values i'm working with are in nautical miles. The definition
of a nautical mile is 1 minute of 1 degree.
Since this unit of measurement is based on a degree, and WSG84 is based
on degrees of lat/long (and
Thanks Regina that is it, I didn't have the right projection to begin with.
I needed NAD_1983_StatePlane_Nevada_East_FIPS_2701_Feet
and I was using NAD83 / Nevada East
The projection I needed wasn't in the default spatial_ref_sys? I assumed all
of the srid's would be in there, I guess not? I
RH,
I'm not aware of an easy way to tell if its in range (I think you can
from the proj4text lon a b blah blah blah args) defined in
spatial_ref_sys, but I'm not that technically savvy.
If you get something like all the same long lat when you project back
to 4326 (WGS 84), or you get weird numb
Ok, yikes. This is suddenly getting much more complicated than I
originally thought.
Yes, obviously the boundary approach does not take into account if the
point is inside a country polygon.
Also, the problem with your second attempt was that you were grabbing
only the first polygon out of
My version is 1.1.6. Can I upgrade just the PostGIS version without
upgrading PostgreSQL? I am running PostgreSQL 8.2. David
Mark Cave-Ayland wrote:
I have a PostGIS database that is frequently thowing this error. My
guess is that it is related to the GIS index and the number of NULL
geometries
> I have a PostGIS database that is frequently thowing this error. My
> guess is that it is related to the GIS index and the number of NULL
> geometries in the table. Because of how I am using Hibernate, I insert
> the record with a NULL geometry and then update the record with the
> geometry. Has
I have a PostGIS database that is frequently thowing this error. My
guess is that it is related to the GIS index and the number of NULL
geometries in the table. Because of how I am using Hibernate, I insert
the record with a NULL geometry and then update the record with the
geometry. Has anyone
Hi!
I am currently doing research on UML modeling of cadastre and land
administration data. On a Object Diagram, there is a situation where a check
should be done on the projected straights of a building outline (original
building to be depicted in 3D), in order to see if it is contained within
Thanks for the Help Regina, below are some of the points I attempted.
setsrid(MakePoint(834934.2263,26712690.6089, 32107)
setsrid(MakePoint(834533.210694,26712881.1962, 32107)
setsrid(MakePoint(834224.086891,26712318.3331, 32107)
Is there a way to check if it is in the range of the projection
Kevin,
I have played with these functions and created a query however it
does not seem to be producing the correct results.
What I have done is the following (just so you understand the data
that I am working with).
I have downloaded the World shapefile from http://www.cipotato.org/
diva
Hi Mike,
Try ST_Simplify() - the postgis implementation of the Douglas-Peuker algorithm
for point reduction, it is probably closest to what you mention.
HTH,
Brent Wood
--- On Fri, 9/12/08, Elstermann, Mike <[EMAIL PROTECTED]> wrote:
> From: Elstermann, Mike <[EMAIL PROTECTED]>
> Subject:
Hi,
who has a Idea?
You know the "CLEAN"-Statemant in ARCINFO to reduce the number of Nodes within
a tolrance.
I'm looking for the same with PostGIS. I can't find it in the documentation.
Thanks mikeE.
-Ursprüngliche Nachricht-
Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag
Kevin Neufeld wrote:
Yeah, it looks like things got a little jumbled with the new
documentation shuffle.
I've reinstated the link on the documentation webpage to an older pdf I
found (version 1.3.2). (http://postgis.refractions.net/docs/postgis.pdf
). In my spare time, I'll work to update t
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