My impression is that working topologies is slow, especially with large
datasets - lots of computation involved.
How effective would this be with hundreds of thousands or millions or small
polygons?
Just running ST_Union() takes hours to days.
Thanks
Brent Wood
--- On Fri, 10/26/12, Sandro
Hi Rene,
Perhaps something like this?
select region, ST_simplify(ST_buffer(ST_convexhull(ST_collect(geom), n),n/3))
from table group by region;
ST_simplify removes extraneous vertices - increase the n/3 parameter to remove
more vertices, but you'll also need to increase n to ensure all the
Hi,
I'm trying to come up with an approach using Postgis to come up with a polygon
representing the outer bounds of a set of points, ie: a polygon passing through
all the outer points.
Much useful info (as usual - thanks guys!!) at spatialdbadvisor bostongis but
my limited understanding is
Thanks,
All things come to those who wait :-)
My data is 2D at present...
If I can't get thr PL/R solution working I think I'm better off waiting for
GEOS 3.4/Postgis 2.1
Cheers,
Brent
--- On Sat, 9/1/12, Paragon Corporation l...@pcorp.us wrote:
From: Paragon Corporation l...@pcorp.us
Hi James,
I'd do this fairly easily under Linux with a script to iterate through the
tasks. In fact I've done it, we have tracklines recorded for an underwater
cammera. It takes a picture every 15 seconds, so I navigate along the line in
15 second intervals to get the points.
As you describe,
Hi George,
That is not a multi-part polygon (multipolygon). It is a polygon with a hole,
the hole lies outside the polygon boundary so it is going to give weird
results. I'm guessing that what you actually mean to do is not:
psql -d test -c SELECT st_area(ST_GeomFromText('POLYGON((-1 -1, 2
On Thu, Aug 02, 2012 at 05:41:23PM -0400, Jean-Daniel Sylvain wrote:
Hi,
Is it possible to create overviews in postgis to optimise the speed of
display for very big vectorial dataset (10 000 000) ?
The aim is to be able to look quickly the dataset via a GIS tool like
Quantum GIS or GV
You have not just a spatial dataset but a temporal one as well.
You need to define how near the buoy you consider is going past it (a pass)
You could wrap an SQL around this, but if you were to use a script to carry out
the query, the logic would be something like:
1. get the minimum time for
Coming from New Zealand, near 180, I think it is fair to say that a geometry
with
left lon right lon is not wrong. Just that Postgis fails to interpret such
correctly.
A polygon such as POLYGON((179 -45,181 -45,181 -46,179 -46,179 -45))
is obviously crossing the dateline, and is
You could try something like gdal2xyz.py on you raster to create points for
each raster cell which can be imported directly into postgis as point
geometries, like:
psql create table xyz (id serial,x decimal, y decimal, z decimal)
gdal2xyz.py raster file | psql copy xyz (x,y,z) from stdin...
which you can
use as topopolygons or extract as conventional geometries.
--- On Tue, 5/15/12, george wash gws...@hotmail.com
wrote:
thank you pcreso, I had a look at the topology
section
You can work around this problem by using the Postgis topology capability. It
will build polygons (faces) from such lines which you can use as topopolygons
or extract as conventional geometries.
--- On Tue, 5/15/12, george wash gws...@hotmail.com wrote:
From: george wash gws...@hotmail.com
OK,
In my case the linestrings I was constructing polygons from did not have aligned
start/end points (nodes), so I loaded them sequentially snapped nodes to
pre-existing ones, to generate faces in the topology.
I did not use a topogeometry column at all, but extracted the topology faces
It looks like you are missing a quote in your data statement after 'asdf
and my have an extra one at the end?
That might help...
Brent Wood
--- On Sat, 5/12/12, abhishek bansal discover...@gmail.com wrote:
From: abhishek bansal discover...@gmail.com
Subject: [postgis-users] PostGIS Raster
Hey Ben,
How goes it?
Does
http://postgis.refractions.net/documentation/manual-1.5/ST_NumGeometries.html
do what you want?
FYI, I was interested in this post, as a PL/R user it may interest you as
well?
Hi Shaun,
You add a geometry column to the table, then run an update sql to populate it.
eg, assuming your table is called mytable, located in the public schema, you
want to create a two dimensional point with lat/long coordinates (EPSG:4326)
called geom:
select
Hi,
Can anyone explain this message to me whether it indicates anything I should
be concerned about?
The stations table contains some 47,000 undersea sample sites. The other tables
represent points of observations of various properties such as depth or
temperature.
The query is to return an
Found the answer Thanks list :-)
http://postgis.17.n6.nabble.com/LWGEOM-gist-joinsel-called-with-incorrect-join-type-td3535176.html
--- On Tue, 4/24/12, pcr...@pcreso.com pcr...@pcreso.com wrote:
From: pcr...@pcreso.com pcr...@pcreso.com
Subject: [postgis-users] LWGEOM notice message - what
I'm doing some left outer spatial joins using the operator, which should be
relatively quick.
When I join across 5 tables, the result is fast enough, explain shows index
scans are being applied to the spatial tables. When I add another table,
explain shows a seq scan is used, despite the
Hi Michal,
One suggestion...
There are two ways (at least :-) to do this in a RDBMS. You can have the
spatial relationship implicit in the feature geometries, so a spatial query is
used, for example, to determine the cities within a country:
select * from polygons a, polygons b
where a.type
Are you planning to store multiple versions of these polygons, for zoom layers?
Generally you need a high res version (eg: coastline) when zoomed in (large
scale) and a lower resolution version when zoomed out (you can't see don't
need the detail.
This may or may not have an impact on your
Hi,
The attached script creates a Postgres database, adds Postgis with topology
uses linestring geometries as the underlying data to create topologies, then
extracts the generated faces as simple polygon geometries.
It was a useful learning exercise for me to put this together, with advice
Hi Dave,
I would have thought ST_Simplify() would met your requirements.
If you use it with a buffer distance of zero, then the full resolution is
retained, but any points on a straight boundary segment which are redundant are
removed. This is the minimum number of vertices required to define
Following on from the reply by strk (thanks!!) I'm still working through how to
use topologies.
I have a script which creates a topology, adds 5 linestrings looking like:
| | |
---
| | |
---
| | |
validates the result and then
Thanks again for a prompt reply.
QGIS is showing the results of the inserts polygonise in the attached image.
So, yes, just as you sketched it.
I had assumed Polygonize was constructing polygon TopoGeometries ?? Obviously
I've missed something somewhere.
I can find no info at all on the
I'm after some pointers on how I might use topology in this case:
We regularly undertake random stratified two phase trawl surveys for fisheries
stock assessments.
This requires the survey area to be divided into arbitrary strata, with sample
sites randomly defined for each strata. Generally
Whenever the intersection of two lines is a linestring.
eg:
select astext(ST_intersection(ST_makeline(ST_Makepoint(0,0),
ST_Makepoint(1,1)),ST_Makeline(ST_Makepoint(0.5, 0.5), ST_Makepoint(1.5,1.5;
astext
-
LINESTRING(0.5 0.5,1 1)
(1 row)
Brent
Hi,
No mercator projection can encompass the poles, as they are asymptotic the
latitude values approach infinity.
Because the Mercator projects the poles at infinity, Google Maps cannot
show the poles. Instead it cuts off coverage at 85° north and south.
Brent Wood
--- On Fri, 3/16/12,
Hi Nicolas,
Change your SQL to insert a buffered version of your polygon with a buffer
distance of zero. You should get a topologically correct polygon (in this
particular case anyway), which is a tracing of the perimeter with any duplicate
vertices resolved.
eg:
insert into test_polygon
I forget where I learned that... probably from Regina Obe at Boston GIS.
Also note that from the picture, it should perhaps be a multipolygon, to store
a single feature comprising two polygons sharing a point... rather than a
single polygon.
Cheers,
Brent
--- On Sun, 3/11/12, Puneet
See the tutorials here:
http://www.bostongis.com/PrinterFriendly.aspx?content_name=postgresql_plr_tut01
http://www.bostongis.com/PrinterFriendly.aspx?content_name=postgresql_plr_tut02
http://www.bostongis.com/PrinterFriendly.aspx?content_name=postgresql_plr_tut03
They may be of some help.
ST_Buffer(linestring, distance)
http://www.postgis.org/docs/ST_Buffer.html
Note that if your data is lat/long (such as EPSG:4326) with units in degrees,
then you will get somewhat distorted buffer distances, and a better result by
transforming your linestring to a more suitable projection for
I use a custom equal area projection for some large oceanic regions I work in,
but depending on the extent of your linestrings, it is likely that the UTM
projection for your part of the globe will give a reasonable result, if you are
not too near the poles.
You may even find native lat/long
Does this work?
UPDATE gis.gz_2010_48_160_00_500k
SET the_geom_3081 = ST_Transform((ST_Setsrid(the_geom, 4326),3081);
ie:: is the problem finding the srid from geometry_columns or finding it but
ST_Transform() fails even when given the srid?
Even if there is a bug, this
Hi,
Not having tried this, but perhaps:
Use ST_Polygonize() on the linestrings as in the example here:
http://postgis.org/docs/ST_Polygonize.html
You could use ST_Dump() to return the polygons wrap it up in count() for the
where clause, so only linestrings able to generate one or more
Also,
In Postgis you can use the ST_Simplfy() function in mapserver zoom (scale
dependent) layers. So you have one dataset, and as you zoom out you display
features represented by progressively fewer vertices. You don't need every
headland of a global coastline dataset plotted until you until
That is the name you are giving the index. It is good practice for the
name to include the table column(s) the index applies to in the
name you give it.
--- On Wed, 2/15/12, Bistrais, Bob bob.bistr...@maine.gov wrote:
From: Bistrais, Bob bob.bistr...@maine.gov
Subject: Re: [postgis-users]
Nothing obvious that I can see.
psql -d db
\d # should list the tables
\d mytable # should list the structure of the table mytable
select * from mytable; # should list the contents of mytable.
If you can post the outputs from these commands (the text before the #) we
For Linux, it has been available for some years. If you need 64bit support, you
might consider upgrading :-)
Cheers
Brent Wood
--- On Sat, 2/4/12, CARLOS MUÑOZ cjmun...@yahoo.com wrote:
From: CARLOS MUÑOZ cjmun...@yahoo.com
Subject: [postgis-users] Postgis for Postgres 64 bits
To:
When did this become available?
I'm using pgsql2shp from Postgis version 1.5.3 for Linux, which is pretty
current, and that is not a listed command line option.
Cheers,
Brent Wood
--- On Mon, 1/30/12, Richard Greenwood richard.greenw...@gmail.com wrote:
From: Richard Greenwood
Hi Daniel,
The GUI is only available for Windows, which I haven't used much for some years
now. So I can't help with that aspect. I would assume the GUI has some way for
you to enter the same parameters.
As often as not, I find a GUI is an intermediary between me the application I
want to
pgsql2shp -s 4326 -I shapefile mytable | psql -d mydb
where
shapefile is the name of your shapefile, eg: myfile.shp
mytable is the name of the POstgis table to create populate
mydb is the name of od the Postgis database (Postgres with Postgis installed)
-s 4326 tells pgsql to create a table
Hi Daniel,
There are two common ways to do this, using ogr2ogr or shp2pgsql.
I suggest you try shp2pgsql as it has a simpler command line. It is a utility
bundled with Postgis. If you run it with no arguments it provides help with the
syntax.
The default ouput goes to stdout, and comprises a
Hmmm
I believe Ubuntu, Debian, OpenSuse, Fedora, etc all have Postgis in 32 64bit
prepackaged ready to install.
https://wiki.ubuntu.com/UbuntuGIS
http://wiki.debian.org/DebianGis/PackageList
http://fedoraproject.org/wiki/GIS
Hi Daniel,
The docs are a good place to start, but here is the simple version, from the
command line...
If you have got Postgres installed OK, you need to create a new database, then
install Postgis into it, so I'm assuming you have a working Postgres superuser
account you can use. Then:
#
Puneet,
Chopping polygons is pretty simple, with a grid st_intersection(), but you
can certainly generalise polygons to reduce the number of vertices size of
objects to de-toast... beware however that if you do this then you are actually
moving the polygon boundary, therefore a point very
Try this:
Create a table with chopped up polygons derived from your continents table.
Say you have continents (continent_id, name, the_geom)
then you have continents_chopped(chop_id, continent_id, continent_name,
the_geom)
Spatial index on continents_chopped.polygon
SELECT Count(distinct
Hi Steve,
I figure I'll give you the long version :-)
We use SLES 11 at work (NIWA, New Zealand) for several servers running
postgis/mapserver/etc. The public web mapping portal at
http://www.os2020.org.nz has most of it's map layers served from a SLES VM
running postgis/mapserver. (The slow
try something like
select placename from table where ST_Contains(geom,point);
This will return the placename for all polygons (geom) which contain the
specified point.
HTH,
Brent Wood
--- On Mon, 11/7/11, Torsten Mohr tm...@s.netic.de wrote:
From: Torsten Mohr tm...@s.netic.de
Subject:
I have converted such grids to XYZ points using GDAL stored them as Postgis
points, but ensure you are clear about your pixel vs grid registration (are the
XY coords at cell origin or centre?)
I'll leave it to you to determine whether upgrading to a version supporting
PGRASTER is viable or
Hi Phil,
If your view is large, you will get sluggish performance with QGIS. One
solution is a materialised view, which is not directly supported in Postgres,
but can be made to work. This does create a physical table representing the
view, which can have appropriate indexes applied.
The
The issue is that you are trying to install an old version of postgis into the
new database.
My normal approach (yet to fail - for me at least):
create the new database
install the appropriate/current version of Postgis in that db (this may require
plpgsql as well as running postgis.sql
Welcome to maritime GIS around New Zealand :-)
The standard problem!
Work in a 0-360 space instead of +-180. EPSG4326 supports both extents
(according to EPSG anyway). The problem is the lack of a flag to specify which
you want.
Improvements in the geography datatype will help in this area.
Not quite.
You need to reproject the lat long coords to 29101 before writing them to your
table.
Your first SQL creating the column is fine, the second update needs changing.
UPDATE tablename SET geom_col =
st_transform(st_setsrid(makepoint(long_dd,lat_dd),4326),29101);
this:
creates a point
Hi,
Yes you can, you use the case statement.
Here is an example:
create table ttt (id serial primary key,
geocode varchar(12),
lat int,
lon int);
insert into ttt values (default, '1234/5678', null, null);
insert into ttt values (default,
Glad it helped.
You can do that, but that is simply using Postgres columns, you do not require
Postgis geometry capabilities to do that. I recommend you avoid upper case
characters in table column names, otherwise you'll need to quote them.
alter table tablename add column lat_dms int;
Instead of storing lat long columns of numbers, create a point geometry with
Postgis, you can still select the lat long values as shown below.
select addgeometrycolumn('','tablename','geom',4326,'POINT',2);
To run this change 'tablename' to the name of the table with the geocode
column.
Hi Paolo,
A quick reply, I don't think this is the place for a long discussion :-)
Have a look at the cartographic capabilities of GMT. Framed, annotated borders;
legend composer; A0 poster size, etc; rotated extents, 3D perspective views;
global projected maps; etc. I can send you plenty of
Yep, someone thinks QGIS can clip better than Arc, so can Postgis AFAIK. That
doesn't make either more powerful than ArcGIS.
I've been using QGIS in a production environment, since v0.2, Postgis since
v0.7, GMT since 2.x (I think). I work in what is largely an ESRI house for
GIS purposes,
Hi,
Assuming your cities are point features and you have some column to aggregate
on (like name?) try something like this:
select setsrid(makepoint(avg(x(geom)),avg(y(geom))),4326) as geom,
sum(pop_1990) as pop_1990,
name
from cities
group by name
ORDER BY pop_1990 DESC LIMIT
Use ST_buffer, as below:
create table mline (gid serial primary key, name varchar(10));
select addgeometrycolumn('','mline','geom',4326,'MULTILINE',2);
insert into mline (name,geom ) values
('one',setsrid(geometryfromtext((174 -45,175 -44),(174 -44,175 -45)),4326));
insert into mline (name,geom
I'm not conversant with geoserver but have used mapserver to do this sort of
thing often enough.
I assume your data is in PostGIS, which means your mapserver DATA statement can
be an embedded SQL query or a PostGIS view.
You can create a view on your table, along the lines of:
create view
Hi James,
I suggest you avoid upper case letters in table column names if you can. It
makes a few things easier
The syntax in both SQL statements is wrong. Try:
select
ST_CreateGeometryColumn('public','CLEANEDCAMDENGPS','geom',4326,'POINT',2);
the fields are (in order):
schema where
Hi Mike,
Look at case in your SQL, might meet your needs if the
ST_contains()/ST_covers() function reuslt is cached in a select statement,
which I think it is now, will be reasonably effective.
http://www.postgresql.org/docs/9.0/interactive/plpgsql-control-structures.html
select case when
This query from
http://postgis.refractions.net/pipermail/postgis-users/2009-April/023265.html
should give you an idea of how to do this.
The radius is an arbitrary value to avoid a full table scan.
If you already know which feature is closest just want the
closest vertex from that feature,
I foubd this an unfortunately ambiguous name.
it doesn't populate geometry columns so much as update the geometry_columns
table.
But irrespective of the name, it is nice to have :-)
Cheers
Brent Wood
--- On Thu, 5/19/11, Ben Madin li...@remoteinformation.com.au wrote:
From: Ben Madin
I'm not sure if is just the email doing it or if your CONNECTION string is
entirely on one line or not. You might try having a single line if it is
wrapped.
You can enable DEBUG in the mapfile see any error messages.
http://mapserver.org/optimization/debugging.html
eg:
MAP
...
CONFIG
Hi Aren,
If I understand the question, then off the top of my head, untested without
getting into calculating spheroidal distances instead of cartesian ones :-) ...
given a table loc_table with columns:
ref_mark_id
location (point geometry)
something like:
select ref_mark_id,
I'd try a different approach to loading your data into the table.
Try loading your lat/lon values using copy. This will be fastest (specify the
field delimiter char): eg: cat file | psql -d db -c copy table from
STDIN with delimiter '?';
Then add your geometry column to the table.
select
It is likely to be the fastest waty to initially populate the table as a bulk
insert. There is nothing stopping you adding rows later however you like. I
have populated tables with 250,000,000+ rows like this.
The advantage is that once the data is loaded without constraints, you can run
02c worth strictly from a user's perspective:
New users will generally start with current latest versions. So they should be
fine.
Old users who have difficulty upgrading. (Oft times me :-) my call. If I need
Postgis to work with 8.3, I use v1.5, if I need later Postgis functionailty, I
Concatenation of strings geomfromtext or cast to numeric makepoint, I'm not
sure which would be faster, but both will work.
So (as below)
update mytable set the_geom=ST_GeometryFromText('POINT(' || long || ' ' || lat
|| ')',4326)
or
update mytable set
Hi Oscar,
Unless I'm missing something here...
Can you
open the array up in a query/view so the elements become columns for the
web service? While an array is convenient within Postgres, it is a
non-standard not widely supported capability, as is the user
defined composite data type.
It
Hi Robert,
Can you do turbines as WFS with one of the fields the URL for the image, so the
client has the image URL readily available? Or if you stick with WMS, you can
still query the feature to get the URL of the image, see how to set up a query
layer via your WMS server application.
Brent
Hi Peter,
It sounds like you are wanting to tile your polygons. Not really ideal, as each
polygon is rendered via tiles, so you need to render them without borders to
hide the tiles, then often plot the border as well, which still has all the
vertices. Lots more work.
You might look at
Hi Colin,
Given your definition of adjacent, you are probably better off with a script
using sqls to retrieve data/write result the script to implement the logic,
iterating through the polygons:
foreach polygon (a)
foreach different polygon (b)
foreach a.vertex
foreach
Would it not be simpler to use ST_Distance?
Unless I'm missing something, the tolerance is the minimum distance between two
polygons, so:
select a.id as poly_a,
b.id as poly_b
from mypolys a, mypolys b
where a.id != b.id
and ST_Distance(a.geom, b.geom) = tolerance;
to add some
Hi Ravi,
Sounds like you are dealing with point features, with a single coordinate pair.
So if that is case this should help.
If you know the coordinate system they are in, you can tell Postgis to use that
transform the points to a lat/long geometry, as below. Posdtgis cannot detect
a
Hi,
You can use simple SQL to extract core values which you manipulate analyse in
PHP/Javascript, or you can do more of the work in SQL. Given your skills, it
seems likely that you would find it easier to use simple SQL more script
based processing.
One initial point to note:
If you are
Hi Ben,
I'm interested in what an authoritative answer is to this :-)
I know that several years ( Postgis/Postgres versions) ago running a query on
this setup, then dropping the original column vacuuming re-running the
query didn't make a significant difference, coz I tried it, but this was
Hi Aren,
for start end points you can use ST_StartPoint ST_EndPoint, should be
faster than 0 100% values.
It may also be useful to optimise your working data, by pre ordering the points
so that the startpoint is always the southern or western one, so your algorithm
does not need to check
Hi,
You need to have your points already in a table, then you can run a single
query to identify the county each lies within.
SELECT p.point, c.county_nam
FROM county c,
points p
WHERE ST_Within(p.the_geom, c.the_geom);
You can also wrap this in an update statement to have a
Hi Aren,
In this sort of case I usually prefer to keep my source data as a reference, as
well as an indexed reprojected (working) version of the geometry. Instead of
doing it as you have done, and create a new table, I add a new geometry column
of the appropriate type SRID to the original
Hey Ben...
Seasons greetings!!
You have a couple of options:
ST_Translate() is the simplest, but if your lines are horizontal you may want a
Y shift as well?
http://postgis.refractions.net/documentation/manual-svn/ST_Translate.html
Having done this, I suggest you also use ST_reverse() to
On ubuntu, some issues as postgres 9 required postgis 1.5.2, which when I
installed it had to be built from source as a package was not available.
I followed ( corrected) these instructions
Hi Kevin,
I'm increasingly impressed with the analytical capability of Postgis, and with
how fast it is increasing. I can do ( have done) pretty substantial analytical
processing totally within the db, and have tools like QGIS to visualise the
results GMT for publication quality cartography.
Hi Sébastien ,
One way I clustered points in the (distant) past for a zoom-layer mapping
solution was to create multiple geometries, by reducing the number of decimal
points in the X Y coords and grouping by these locations. Simplistic not
especially statistical, but given a random point
Hi Vinicius,
If SuSE created a Postgis enabled template, you could use that as the basis for
your new database, so it will already have Postgis installed.
Otherwise use the usual commands to install Postgis in a Postgres database:
createlang plpgsql new db (not needed with Postgres v9.0+)
Hi Sébastien,
Sounds like an interesting situation :-)
You might look at the newish (v8.4+ ?) RECURSIVE/WITH capabilities of Postgres.
Given Postgis allows you to create arbitrary buffer zones around your points,
the RECURSIVE query capability allows you to write an SQL that will recursively
Which version of PostGIS is on each box?
One q'n'd approach which works for me is to create the target db manually,
install Postgis into this manually, then use pg_dump src db params | psql
target db params
Brent Wood
--- On Tue, 12/7/10, Vinicius vinicius...@gmail.com wrote:
From: Vinicius
If you simply want to reduce the number of features to load in each iteration,
why do you need to use a spatial predicate, you can determine the count of
records (~130,000) then use:
select ... limit offset ;
Iterate through until done. Your features will not be spatially grouped,
Hi David,
You can use PL/R to access R functionality from a Postgres SQL command line, or
you can use rgdal to read Postgis data into R.
So it depends on whether you want to work in the DB add R capabilities, or
work in R access Postgis data.
See:
Hi,
If I understand the question correctly, you want to identify polygons which are
outside of a polygon (including inside the hole of another polygon) but within
the outer polygon perimeter.
You can do this with a self relation (join a table to itself). Something like:
select t1.name from
Paul
I suggest you chaeck the XY coords in your data, it looks like you have
mislabeled lat lon, your lat values are 90 180.
If you have loaded these into Postgis with the coords reversed, then they will
not be in the correct location, which could be why ST_contains fails
Brent Wood
---
Hi,
I have a set of 155,000,000 points on a regular grid. I need to convert these
to a set of square polygons covering the area represented by the points.
Can anyone suggest how this could be done in Postgis?
Thanks,
Brent Wood
___
postgis-users
Or look at using GMT (Generic Mapping Tools) to render your maps.
Pretty easy to script up something like:
for dataset in table ; do
get data (ogr2ogr)
render map
done
GMT is perhaps the most powerful Open Source cartographic tool available, but
does not integrate particularly well with
Hi Luis,
With option 2, all the errors are about a failure to create objects (postgis
functions spatial_ref_sys entries I assume).
Why is this a problem for you? They already exist so do not need to be
reinstalled, the rest of your database should be installed, so you should have
a fully
V 8.4 of postgres supports recursive (heirarchical) queries, which may be able
to do something useful in this area.
Cheers,
Brent Wood
--- On Thu, 7/8/10, Birgit Laggner birgit.lagg...@vti.bund.de wrote:
From: Birgit Laggner birgit.lagg...@vti.bund.de
Subject: Re: [postgis-users] ESRI
This is also an issue for geometries, but I'm looking for a geography solution
here.
How can I create a geography that goes from -90 to 90 crosses the dateline vs
one that goes the other way around the globe crosses the 0 degree meridian?
Either/both is defined by:
POLYGON((-90 10, -90
Hi,
We use an application much like this for generating random sample points for
2-phase random stratified trawl biomass surveys. Specify polygon name, number
of points, minimum distance from the boundary, minimum distance between points
in a file, then iterate through the file.
The code has
1 - 100 of 158 matches
Mail list logo
