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

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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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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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342 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 ...
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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 ...
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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 ...
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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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Support for PostgreSQL / PostGIS Inherited Tables in MapInfo/QGIS

Does anyone know if MapInfo and QGIS will support inheritance in a PostgreSQL/PostGIS database? I would like to make use of inheritance but need to make sure the software I use will work with them. ...
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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: ...
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grib2 to raster? (grib2 -> raster2pgsql -> PostGIS 2.0 -> GeoServer)

I'm looking to implement import of US National Weather Service data for doing various sorts of models (www.soils.wisc.edu/uwex_agwx if you're curious about what we're doing with the data). The ...
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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, ...
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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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622 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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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 ...
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4answers
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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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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 ...
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QGIS, Postgis: Geometry type does not match column type

I'm trying to import some polygon shapefiles to Postgis in QGIS via SPIT. One of them can't be imported and returns this error: ERROR: Geometry type (Polygon) does not match column type ...
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480 views

How to query OSM for all beaches facing west? - QGIS preferred

I want to identify all beaches on this planet (or a given subset of it) that are facing westwards (+/- 20-30 degrees). My idea is to use OSM as the data source. Extracting all polygons that have the ...
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Creating spatial tables with PostGIS

In the PostGIS documentation it says that there are two steps to creating a spatial table with SQL: Create a normal non-spatial table. Add a spatial column to the table using the OpenGIS ...
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GUI tools for PostgreSQL/PostGIS?

as a cartographer I work with TileMill to visualize geodata. I installed a local PostgreSQL server with PostGIS and osm2pgsql. Everything works fine. Anyhow, I am new to working with servers and the ...
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Are there any tricks to using a schema other than public in PostGIS?

I'm currently setting up a fresh install of PostGIS 2.0.2 and PostgreSQL 9.1.6 on Ubuntu. I've recently come across some information indicating that using the public schema to store all data is not a ...
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How do you protect your PostGIS credentials when using QGIS 1.7?

I'm fairly certain this should be a community wiki, but I don't know how to make it one. So if an admin sees this please change if appropriate. So.....How do you protect your PostGIS database data ...
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How to visualize measure values along linestrings in QGIS?

I have a series of LineStringM geometries. The measure value represents slope (or stream gradient) at each point in the geometry. I love QGIS's robust styling options, but I can't find a way to render ...
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How to view a 155 MB raster stored in PostGIS?

I am using the following command to load a raster into a postgres database: raster2pgsql -I -C -e -Y -F -s 3086 -I -C -M myraster.tif myraster -F -t 30x30 | psql -U postgres -d database -h localhost ...
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Postgis - Converting 'geometry_dump' data type to a 'geometry' type

I am working with a dataset of property boundaries that has had ST_Union() run on it, thus all the polygons appear as a multi polygon in one row of a table. I would like to separate these out so I get ...
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899 views

How to Simplify a Line Network Preserving Topology?

I have a Shapefile (consisting of European major roads) with about 250.000 Segments which I have to simplify for pgrouting. But I can't seem to find a way to do that properly. This is what it looks ...
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Beginner PostGIS question: getting geometry from multiple tables

I am very new to PostGIS, PostgreSQL, and SQL in general. I have 44 tables in my PostGIS database, and each one represents a different layer of vector data. Each was loaded from a separate shapefile, ...
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Find headwater polygons

This is a follow up question to this question. I have a river network (multiline) and some drainage polygons (see picture below). My goal is to select only the headwater polygons (green). With ...
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2answers
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Using ArcGIS and QGIS together in multi-user editing environment?

We have a GIS staff of 7, and another group of about 14 who "use GIS" from time to time. We really, really want multi-user editing. Mostly of a large point file, and we're almost never in the same ...
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600 views

How do I calculate Manhattan distance with PostGIS?

I am using the ST_Distance function to calculate the distance between two geometries (a train station and a building) Since I know that all buildings and all train stations are in Chicago, which has ...
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1answer
949 views

Performance in calculating raster statistics in PostGIS

I'm trying to calculate raster statistics (min, max, mean) for each polygon in a vector layer using PostgreSQL/PostGIS. This GIS.SE answer describes how to do this, by calculating the intersection ...
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PostGIS select by lat/long bounding box

I have a minLat, minLong, maxLat and maxLong from a box drawn on a map. Right now, my query to get all the points in the box looks like this: SELECT * FROM geomTable WHERE (longitude BETWEEN minLon ...
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How to add vertices to existing linestrings?

If I have Linestring(1 2, 1 5, 1 9) and a Point(1 3) Is there any function that can merge linestring and point preserving the order so output would be: Linestring(1 2, 1 3, 1 5, 1 9)
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Ring Self-Intersections in PostGIS

This is a follow on from previous question. You will see I am a new PostGIS user. I have looked at the validity of the topology in my data and find around 1700 topology issues in the landcover ...
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4answers
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Looking for a basic PostGIS viewer to use as basis for own application

I'm looking for a rather basic PostGIS viewer. It should be possible to pan, zoom and retrieve coordinate information on mouse click. No need to support coordinate transformations. It should introduce ...
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1answer
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How do I optimise performance on a local QGIS + PostGIS installation?

I'm learning how to manage a local PostGIS (ver 2.1) database, with spatial indexing enabled on the shapefiles that I've imported (using the PostGIS Shapefile Import/Export Manager). I have imported a ...
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How to extract POINT from a [LINE|MULTILINE]STRING

I'd like to create a vectorLayer in QGIS to display all the points that form a LINESTRING or a MULTILINESTRING stored in a PostGIS DB. I think that I need to transform all points of LINESTRING (or ...
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1answer
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Why do simplify polygon results differ between ArcGIS for Desktop and PostGIS?

I am mainly interested in why and how the Simplify Polygons tool in ArcGIS for Desktop handles the simplification process, including preventing and resolving topological errors better than the ...
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2answers
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How to run two PostGIS versions in parallel on Windows?

I'm trying to understand how to install PostGIS2.0 on Windows7. The PostGIS site has the following suggestions: PostGIS Experimental Binaries PostGIS 2.0.0SVN Binaries with Raster, Topology ...
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Performance Gain Through GIST Index for Point in Polygon Query

I have two tables: locations(id,region_id,the_geom) and regions(id,the_geom). For each location point I want to determine the region it is located in: UPDATE locations SET region_id = (SELECT id ...
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1answer
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Configuring Geoserver to use a specific postgis geometry column as the default

I have a PostGIS table with two geometry columns, both multipolygon but one with SRID 4326, the other 3857. When publishing the table in Geoserver, I realize that Geoserver defaults to using the first ...
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What is the easiest one click install method for PostGIS and it's entire dependencies?

For someone new to database servers and their dependencies, what is the easiest assured way of installing PostGIS on a machine with no other software beyond what comes with its operating system? I'd ...
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How to fix performance problem in PostGIS ST_Intersects?

I'm a newbie in postgis and I have a problem in query performance. This my query: SELECT DISTINCT ON (userid) userid ,ST_AsText(position), timestamp FROM table1 WHERE ST_Intersects ( ...
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1answer
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How to measure length of line accurately?

In postgis 1.5 for the below given query the answer is 1540651.62674101 meters , SELECT ST_Length(ST_GeomFromText('LINESTRING(77.83042478941326 9.98463896136159,78.03469506809812 23.90398909552571 ...
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Is the Fourth Dimension used in GIS?

Whilst working with OGR, I came across the following field used define a geographic dataset: COORD_DIMENSION The spatial dimension (2, 3 or 4 dimensional) of the column. Whilst I've used 2D and 3D ...
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Postgis 2.1 error after update

After a usual update progress - "apt-get upgrade" - I can not connect with qGIS to my PostGIS DB anymore. Error in the qGIS logfile: Your database has no working PostGIS support. Erroneous query: ...
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What's the fastest way to do a bounding box query in PostGIS

I have a Postgres table, with almost 2 million rows, with a long-lat coordinates field in the form POINT(-73.4938 33.2405). Supposing there's a geospatial index on that field, what's the most ...
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How to detect duplicates and keep only one?

I've got a table with lots of points (200.000). Some of them are duplicates (not exactly but e.g. a metro station has eight entrances) and I want to keep only one of these metro entrances. I am able ...
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Rasterize a vector layer in PostGIS

Related to this question asked here on gis.se and this thread on postgis-user, has anyone worked out a good solution for in-database rasterization of a vector layer using PostGIS? It sounds like the ...
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1answer
125 views

Invalid GeoJSON when inserting data to a CartoDB (PostGIS) table from Leaflet

I've been following along to this tutorial from CartoDB. I create the GeoJSON using: var drawing = "'"+JSON.stringify(layer.toGeoJSON())+"'"; and then inserting using a custom SQL function ...
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1answer
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Where to find shp2pgsql windows binaries?

Is there anywhere available shp2pgsql binaries for windows without installing the whole PostGIS? I particularity need the command line version of that import tool. I would like to share a batch ...