PostGIS is an extension for the PostgreSQL object-relational database that adds support for geographic objects.

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Total great circle distance along a path of points (PostGIS)

I am looking for an SQL query that sums the distances between a series of points using PostGIS. The situation is as follows: I have 2 tables: tracks and points. Points belong to a track and thus ...
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5answers
9k views

How best to fix a non-noded intersection problem in PostGIS?

I'm using a PL/R function and PostGIS to generate voronoi polygons around a set of points. The function that I am using is defined here. When I use this function on a particular dataset I get the ...
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2answers
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What are hardware requirements for a cloud hosted PostGIS & GeoServer?

I have been playing with a local installation of PostGIS & GeoServer. I would like to move my work online now to share it with several collaborators. The proof of the concept map will consist of ...
12
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2answers
917 views

PostGIS interpolation / triangulation options

I'm looking for an open source workflow to automate DEM construction. We have a series of sites that fall within a LIDAR dataset. We want to create site specific DEM's for each site, and we're ...
11
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2answers
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How to import esri Personal Geodatabase (.mdb) to PostGIS on Linux

We have esri Personal Geodatabases that we need to import into PostGIS. Ultimately, we'd like to allow people to upload an MDB on a web server, and have it import the layers into PostGIS. On ...
11
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3answers
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How to speed up queries for raster databases?

I have a raster database in postgresql/postgis with these columns: (ID, rast, data_of_data). 'rast' is the column that has raster files in WKT format. An example query to find the DN value of a ...
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3answers
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How to populate an undirected graph from PostGIS?

This question is more related to resources that I might not have identified yet, although I've been searching the web for a while. In the project I'm working at the moment I need to run a shortest-...
9
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2answers
746 views

Are there Desktop GIS alternatives to ArcGIS 10.X for topology and vector conflation?

Is there any options other than ArcGIS for Desktop for topological rules and automatic topology integrity enforcing in a Desktop GIS? I am looking for something that will automatically snap features ...
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Is it possible to geocode street intersections using Nominatim?

Is it possible to geocode the location of a street intersection using Nominatim? Example geocode query Commonwealth Ave at Washington Street, Boston, MA Successful Geocode by Google https://maps....
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4answers
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Queries returning very big datasets in PostGIS

I have a PostGIS query that will return several million rows: SELECT t1.id AS id1, t2.id AS id2, ABS(t1.mean_h - t2.mean_h) AS h_diff, ST_Distance(t1.the_geom, t2.the_geom) AS dist FROM ...
7
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1answer
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Output polygon data from postGIS and read it on Google Maps API

So, I have a group of polygons stored in PostGIS. I'm trying to build a web application with Google Base maps (using Google Maps API). Now, How do i output the polygons in the right format so that ...
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3answers
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Point in polygon algorithm for multiple polygons

I've a Google map with bunch of polygons on it. Here is a problem I'm interested in: Given a lat,lng point, what's the best way to determine all the polygons that this point lies in? The obvious way ...
7
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1answer
853 views

PostGIS Intersection and Summarise Attributes

I am usually an ArcGIS desktop user, but keen to start using PostGIS more and I have a really big bit of processing to do. Not sure what functions to use, hopefully someone can help. I have a polygon ...
7
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1answer
1k views

gdalwarp, cutline and postgis

I can not figure out how I directly can read a polygon into gdawarp's -cutline argument. My current approach is: ogr2ogr -f "ESRI Shapefile" mydata.shp PG:"user=myuser dbname=gisdb" -sql "select * ...
6
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2answers
891 views

How to check if points are within a circular sector using PostGIS?

I want to get the stars within the black region as shown above. To find this I have the centre of circle (lat, long), radius and the angle of region (45 degree). I am new to postgres. I worked on ...
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3answers
2k views

In Qgis, Is it possible to edit the datasource of a Postgis layer?

After creating a layer with RT_SQL_Layer plugin, I want to change some details in the query. Is it possible? or I have to aways create a new layer every time I want to change something in the query? ...
5
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1answer
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How to create a routable road network from Ordnance Survey data?

I've been following the "Beginners Guide to pgRouting" in an attempt to create an in-house application that provides drive-time isochrones. I have a server, postgreSQL and PostGIS and pgRouting - no ...
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4answers
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Calculate min distance between points in PostGIS

I have point layer in PostGIS database. Help please with query which add for each points in layer distance in attribute table between this point and another nearest point. Thanks! Update Calculate ...
4
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3answers
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How to add a polygon from PostGIS ST_AsGeoJSON into Leaflet?

I try to use the following function to add polygons to my Leaflet map. function polygon(geojson) { alert(geojson); // alert for testing layer = L.geoJson(geojson); layer.addTo(map); } ...
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3answers
1k views

Offline Map Service with Mapnik and Leaflet

I'm relatively new to GIS, so I hope my asking doesn't appear to be ignorant in any way. I currently work on an offline map service solution for usage in areas without internet connection. For that ...
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3answers
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How to route between lat/lon pairs in pgRouting?

I have set up Postgresql, PostGIS and pgrouting on Ubuntu. I have imported an osm for wales using the following command: ./osm2pgrouting -file wales.osm \ -conf mapconfig....
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2answers
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How can I calculate the bearing between two points in PostGIS?

How can I find the bearing between two points in PostGIS? Please specify in your answer whether or not the method producing a bearing on the spheroid, or a planar bearing.
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6answers
911 views

PostGIS: Assign ID of point in layer A to closest point in Layer B

This should have been an obvious precursor (that I didn't ask) to my other question: PostGIS function to create spider diagrams? If I do not know the relationship between a point in layer A (stores) ...
13
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6answers
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How to use ST_Intersection?

Here's a quick summary about what I'm trying to do: I have 3 tables in Postgres, 'a' and 'b', each have a Polygon column, and 'c' has a Point column. What I'm trying to do here is to get the ...
12
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2answers
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How to Export Feature GeoJSON from PostGIS

I'd like to do a GeoJSON dump of a PostGIS table, but I want to export features (the geometry and the properties) not just the geometry. I've been digging into the ST_AsGeoJSON function but it looks ...
11
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3answers
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Web mapping software for a huge raster time series?

I'm an ArcGIS Desktop user who is stepping into the world of web mapping for the first time. Following advice I found here on GIS.SE, I started with the free tutorials from OpenGeo. However, I ...
11
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4answers
6k views

How to install PostGIS on Windows?

I want to create an application platform based on PostGIS data. I read the documentation where I saw the prerequisite to install GEOS, GDAL and Proj4. The main problem is I am using windows platform. ...
11
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4answers
813 views

How to add offsets to the route?

Edited: I want to ilustrate my question. Suppose that you're in "Point A" and want to go to "Point B". This points wouldn't be in "at_2po_4pgr" table cause aren't source/targets nodes. Then, I ...
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2answers
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How to preserve topology while editing polygons in OpenLayers?

I’m facing this issue: I have a chloropleth map based on a set of polygons with some data. Using WFS-T (postgis, geoserver, openlayers) I am able to edit the geometry of the polygons. This works fine. ...
9
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2answers
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Storing GML surface in PostGIS

I'm using PostGIS 2.0.0 and would like to store a GML Surface in a way that allows calculating intersections between that surface and various points and lines. In my case, the Surface will have one ...
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1answer
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How to add features to a PostGIS layer using Quantum GIS?

I am using Quantum GIS and the PostGIS dbms. I am able to call the PostGIS layer into QGIS but i am unable to add feature to it. I am using the method of adding features to a Shapefile but still it is ...
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1answer
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PostGIS - Calculate progressive distance between points on a GPX path

I am attempting to build an elevation profile using PostGIS-PostgreSQL only. I have imported GPX data in my PostGis database, so now I have a table full of the GPS coordinates of the track and the ...
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2answers
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Search functionality in Openlayers/Geoserver

I am using Openlayers,Geoserver & Postgis.... My postgis tables are having columns as id, name, POINT/POLYGON/LINE. Each table corresponds to a layer that I am showing in layerswitcher in OL. I ...
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1answer
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PostGIS 3D in Action

I was wondering if there is a website that showcases Openlayers and PostGIS 3D in Action
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1answer
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Import shp to Postgis using Python and ogr

I just export a Postgis Table to shp using this tips but I'm not able to import a shp to Postgis using the same library(ogr). Any idea? Thanks a lot f.
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2answers
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memory issue when trying to buffer/union large dataset using postgis

I am trying to generated a dissolved buffer of a large point dataset (Ideally 29 million points - Address data in Great-Britain, but I receive the data by chunks of 1 million points, so these could be ...
6
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2answers
2k views

How to locate PostGIS AMIs on Amazon EC2?

There are nearly 7000 AMIs on EC2, but I'm having a difficult time figuring out which ones have what I'm looking for--in this case PostGIS on Linux. No specific version/configuation--I want to check ...
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2answers
535 views

How to use interacting PostgreSQL/PostGIS triggers in QGIS to create multiple labels on polygons?

EDIT: The trigger functions posted are well done but there are still a few issues. I've uploaded two screen recordings: http://workupload.com/file/ygRnYtp9 http://workupload.com/file/OBY7i9Fh I ...
6
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1answer
353 views

Maritime route prediction avoiding land masses

I am working on a project where the following functions have to be implemented: Predicting the locations of the ships (in maritime environment) at a future time. (Can be done with Kalman filter, IMM ...
6
votes
2answers
1k views

Split lines at intersection points

I've got some linestrings covering a road network, and need to split them at the crossroads. Does anybody have any idea on how to do it? I'm using QGIS 2.4, with a Postgis 2.1.3.
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3answers
163 views

What is the PostGIS 2.x equivalent of the pre-PostGIS 1.5 ~= operator?

Stemming from my other question: When would a PostGIS geometry compare using ~= return true when ST_Equals returns false?, what is the PostGIS 2.x equivalent of the pre-PostGIS 1.5 ~= operator? It ...
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1answer
190 views

How to install a patch in PostGIS

Can anybody tell me how to install this patch in PostGIS? http://trac.osgeo.org/postgis/ticket/413 http://trac.osgeo.org/postgis/changeset/7534 I need to use the ST_OffsetCurve function. but it ...
5
votes
1answer
1k views

How to route over (partial) edges in pgrouting?

I have made a route planning system (based on shortest path using A*) like the Google directions service using pgrouting and google maps. It includes clicking on the map to generate waypoints, ...
5
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3answers
2k views

How to create random points in a polygon in PostGIS

I have a polygon layer, and would like to generate random points in each polygon. An initial searching in Google resulted this website which presents a function for this purpose: http://trac.osgeo....
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1answer
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PostGIS, create line from points

I have a PostGIS table with position data of numerous vehicles and want to create lines from these points. Data can be selected by vehicle id and ordered by timestamp but how to create lines from the ...
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4answers
10k views

Return all results within a 30km radius of a specific lat/long point?

I have a table with a column the_geom which contains data similar to: ...
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3answers
2k views

Writing a plugin for Qgis using python to access PostGIS and write geometries

Sorry about the strange title didn't really know how to word it. I currently use MapInfo to do most of my GIS work however I have recently installed PostGIS 1.5 and am really liking it so far. A ...
3
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1answer
635 views

PostGIS - when I add a polygon, delete overlapping areas in other layers

I'm starting to work with PostGIS and I'd like to solve the following problem: In my database, I have multiple land use class layers, for example: "residential", "industrial", "commercial". The ...
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4answers
257 views

How can I find features that do not touch any other feature?

How can I find features that do not touch any other feature? I have about 4000 pipeline elements and I want to know which of them are separated from the network. I tried with: SELECT h1.gid FROM ...
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1answer
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Create closest point on multilinestring to use in shortest_path()

I am working a routing based application where I need to create a route between two points of interest. The problem which I am facing occurs after calculating network topology using assign_vertex_id()....