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

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Loading raster from PostGIS DB into QGIS: succeeded yesterday, fails now [closed]

I have a PostgreSQL(v.9.2)/Postgis(v.2.0.3) database which includes raster layers (added through raster2pgsql). To open them in QGIS (v.1.8.0-Lisboa), the "Add Postgis layer" menu will not work; ...
3
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1answer
2k views

convert list of points to line or polygon

I have a list of Points in a PostGIS table. The rows can be grouped by a date something like: myTable id INT date DATE lat NUMBER lng NUMBER geom GEOMETRY(POINT) now I need a table where all ...
3
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2answers
626 views

Merging polygons that intersect by more than a specified amount

I am working with a dataset that contains a subset of property boundaries in a local government area, thus my dataset is made up of several thousand properties but not all are touching. Since it is a ...
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3answers
3k views

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 ( ...
3
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1answer
2k views

PostGIS Error: type “geography” does not exist

I just upgraded my development machine to Windows 7 and am therefore reinstalling PostgreSQL and PostGIS. I used the Postgres Plus installer, as recommended on the Postgres website, and followed this ...
2
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1answer
58 views

PostGIS Raster: Outputting raster into GDAL supported file?

I have import a raster into my postGIS database via raster2pgsql. My raster tiled to 100x100. Now I'm trying to export (output) the raster to GDAL supported file (for example: PNG). Following the ...
2
votes
1answer
410 views

Having trouble connecting QGIS with postgres database with postgis extension

I am working on Ubuntu Precise with postgresql version 9.3 and postgis 2.0. After initially starting my postgres database and eventually getting permission errors that would prevent postgres from ...
2
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1answer
80 views

How to split polygons with another polygon and inheritage data?

Let's say that we have two tables with polygons representing areas. Table A and Table B. Geometries from table A represents both the valid and invalid areas. And the geometries in table B represents ...
2
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1answer
47 views

Nearest neighbour for every row

I'm relatively new to PostGIS and postgresql . I'm trying to build a simple query containing two relations as follows : I've two relations R1 and R2 both of which contains geometries(Points) . I ...
2
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1answer
1k views

Transforming from SRID 900913 to 4326 with PostGis

I have two Postgres tables with different SRIDs, 4326, and 900913. I want to convert the latter to 4236. I first changed the SRID using: Select UpdateGeometrySRID('table', 'geomcolumn', 4326). I ...
2
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1answer
47 views

Compare features in PostGIS with updating attributes

I have two polygonal layers: "existing" and "modified". Attribute table of "existing" and "modified" layers have same column "feature_id" - number of feature. Please help me create query which write ...
2
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2answers
737 views

What Spatial Reference System do I store Google Map's Lat/Lng in

I am new to PostGIS, Spatial Reference Systems and projections and want to store lat/lng coordinates retrieved from Google Maps and Openstreetmap and its services like the Geocoder/Nominatim. I'm ...
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2answers
403 views

Create CMS system using Cartaro

The main objective for our project is to create a portal website in Drupal. On this website, people must be able to upload their geographical datasets (mostly shape files, but also xml files that ...
2
votes
2answers
345 views

How fill length and feature count in PostGIS table for each polygons

I'am new to PostGIS/PostgreSql. I have a database which containts two shape-files : polygonal layer towns and linear layer of roads To calculate the length and feature count of 'Streets' inside ...
2
votes
1answer
419 views

How to debug 'Layer is not valid error' from Python plugin?

I'm trying to understand what goes wrong with a QGIS python plugin. Basically I'm trying to render a series of POINT. The query works fine, at least giving it by hand from inside PostGIS DB: "SELECT ...
2
votes
1answer
245 views

Hyperlinking to PostGIS Layers and Zip files with QGIS Actions

I previously asked a question about hyperlinking data in QGIS that gets loaded into QGIS (see post: Hyperlinking in QGIS - Add Data to current window). A user provided me with the code, which works ...
2
votes
1answer
631 views

Access PostGIS Raster layer through mapserver

I am trying to use a cgi script calling mapserver to display a raster layer that is stored in a PostGIS database. However, only a blank white image is returned and I don't know where the problem is. ...
2
votes
1answer
454 views

How can I get the corners of a polygon in latitude and longitude?

How can I get the corners of a polygon -a square/rectangle, to be precise- in latitude-longitude format by using its geom value -or some other way, perhaps-? Thanks.
2
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1answer
792 views

geoserver wfs insert error

I keep getting an insert error from geoserver when trying to save a point, poly etc etc to my postgis table. any ideas, my code is below var Projection = new OpenLayers.Projection("EPSG:4326"); ...
2
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1answer
609 views

Routing Application in Windows

I am making an routing web application similar to Google Maps 'Get Direction' feature. But because of the limited control and data on GMaps, I decided to use OpenStreetMap instead. This also made me ...
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0answers
194 views

Cannot add the PostGIS raster layer with QGIS

I've imported some raster data in PostGIS database with the following command: raster2pgsql -s 31468 -I -C -M -t 50x50 /home/stefan/Quantum\ GIS/Neumarkt/NM_NW.tif public.demelevation | psql -U ...
1
vote
1answer
185 views

Polygon to fill gap

Using postgis I want to fill a gap between other polygons. Can you help with some directions what functions to use ? Thank you and sorry if the question is rather noobish. Image to explain from ...
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5answers
2k views

Unable to install the PostGIS extension to PostgreSQL on Ubuntu 12.04 LTS

I just installed Linux Ubuntu 12.04 LTS (on a virtual machine). I then successfully installed the PostgreSQL 8.4 database management system. I am now trying to install PostGIS, which is an extension ...
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1answer
315 views

From a trajectory of GPS points to a multiline segment

Given a trajectory as a sequence of GPS points I would like to create a smooth linestring representing a path where a car drove. The data is stored in postgresql: the input trajectory in a table, ...
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vote
2answers
866 views

mulitlinestring to linestring

I am using postgres with postgis and I have a set of points which I would like to interpolate with a set of lines. Now my problem is that the set of lines are of type multilinestring. Is there a ...
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1answer
184 views

Howto setup osm2psql

I'm following these instructions to setup osm2psql . I need it to import osm data file inside a PostGIS DB. The following steps worked fine: createdb -E UTF8 -O user mydb createlang plpgsql mydb I ...
8
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2answers
1k views

PostGIS raster value of a lat/lon point

I have a tiff raster in my PostGIS 2.0 database. I want to get the value of the raster at a specified lat/lon point. I have: postgresql-9.1 postgis-2.0-svn with raster support a raster imported ...
6
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1answer
294 views

Clarification of the “25D” option in ogr2ogr

[EDIT: In my original post, I had received an error that was based on a typo, so I scrapped that part of the question, but left the questions that still apply.] In the ogr2ogr docs it says: -nlt ...
6
votes
1answer
835 views

QGIS WKT Raster Plugin error, what does this mean?

I have been playing with the WKT Raster plugin. I have installed the WKT Raster experimental binaries in PostGIS successfully and followed the instructions in the read me to the letter. When i am in ...
5
votes
1answer
133 views

How to achieve equivalent to Dissolve from ArcGIS for Desktop using ST_Union?

I am trying to achieve an equivalent to the Dissolve tool from ArcGIS for Desktop using ST_Union from PostGIS but it seems I am not getting expected result. I have one table which has certain ...
5
votes
1answer
307 views

How to interpolate polyline or line from points?

We have a lot of points, but with no timestamps to create ways. For now, I've created a sample of the way the points traverse. It's in here, this way can be compared with a Google one. I haven't ...
5
votes
1answer
753 views

Why do TIF loaded into PostGIS lose their colormap?

I have successfully loaded a TIF image (using raster2pgsql) into my PostGIS 2.0.1 database. I can load the raster image into QGIS and it displays in the correct space. However, it has lost all colour ...
5
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1answer
317 views

How to filter points based on proximity while inserting into PostGIS?

I have a large amount of locations that need to be inserted to a PostGIS database. However, I'd like to aggregate these points so that if there's already a location, say nearer than a kilometer, then ...
5
votes
1answer
606 views

How to get GeoNetwork to search through PostGIS fields via GeoServer WMS

I can't seem to get GeoNetwork to search through my PostGIS fields via GeoServer WMS. According to the GeoNetwork Documentation: it should loop over datasets served by the service and produce ...
4
votes
1answer
77 views

Why does only one of the following queries throw an error?

There are 2 SQL queries: SELECT wkb_geometry FROM building_polygon WHERE ST_Contains(wkb_geometry, ST_GeomFromText('POINT (29.4 60.1)')); SELECT wkb_geometry FROM building_polygon WHERE ...
4
votes
2answers
375 views

QGIS saving analysis output as Postgis table

i am using QGIS and Postgis together. I can load data in Postgis and than i import it to QGIS. But i am trying to save an analysis output (example: buffer analysis, voronoi polygon or SEXTANTE ...
4
votes
2answers
202 views

How to find out what features /tags are included in an .osm or .pbf file?

I would like to load osm data into a postgis (postgresql) database. In How to load OSM data into PostGIS preserving all Tags? there has been a solution posted: Download the OSM files (in .osm ...
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votes
2answers
1k views

How to select segment of linestring using PostGIS?

i have PostgreSQL+PostGIS. I have a linestring: "LINESTRING(60.7014631515719 56.8441322356241,60.7023117507097 56.8445673405349,60.702948200063 56.8447993944193,60.703902874093 ...
4
votes
1answer
185 views

Update PostGIS after updating GDAL?

I am using PostGIS 2.0 and I want to use the raster functionality through mapserver. It seems as if the latest official GDAL release 1.9.1 has an unstable PostGIS raster driver, as pointed out in a ...
4
votes
1answer
710 views

Raster data on PostGIS

I need to publish raster and vector data through GeoServer WMS service and I have already chosen PostGIS as datasource to keep vector data. Now I would like to know what is the best practice to work ...
4
votes
1answer
290 views

Self-intersecting polygon using extreme values

I have this polygon POLYGON((1.2E-15 1.1E-15,1.31E-15 1.21E-15,-180 -90,180 90,1.2E-15 1.1E-15)) It uses an extreme coordinates like (1.2E-15 1.1E-15) and (180 90) When I call ST_isValidReason, ...
4
votes
1answer
1k views

Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database

This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc. I have tried the ...
4
votes
4answers
1k views

OSM To Postgis & WGS84 problems

I’m trying to import OpenStreetMap (OSM) data into postGIS it doesn’t appear to be working in that features do not appear to be in the correct place.. Using the QGIS OSM add in and a coastal shape ...
4
votes
3answers
477 views

WFS Caching / Back button

I'm using WFS protocol on Vector layer / GeoServer / PostGIS Currently the map is refreshing and calling new requests whenever i do anything like searching or drawing and when i move back to a part ...
4
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2answers
2k views

Bounding box for PostGIS table

Is there an easy way to get the bounding box for an entire table in PostGIS? Thanks
4
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2answers
586 views

Indian Latitude Longitude values

I am in need of around 10000 and odd Indian latitude and longitude values for my openlayers project. I have to load them in a postgis db. so a sql file or atleast text file would be better than a ...
3
votes
3answers
175 views

Best choice for building static maps: PostGIS, SpatiaLite or Shapefile?

I usually build static topographic maps, which are mostly printed. I'm often using OSM and rasterfiles (mainly different DEMs). The areas I'm mapping seldom exceeds 20.000 km². I'm using exclusively ...
3
votes
1answer
78 views

How to transform a set of street-segments into city-blocks, with PostGIS2?

Theoretically is possible to obtain the polygons of city blocks (urban blocks) from streets, when streets are represented by street axis (LineStrings). The urban blocks are bounded by streets, so ...
3
votes
4answers
1k views

How to convert multipoint layer to point

I have a Spatialite layer which is multipoint (following a QGIS Save As from shapefile). I need it to be PostGIS and POINT. I have tried ogr2ogr -nlt POINT and got 'new row for relation "xxx" violates ...
3
votes
3answers
359 views

Create a point x meters from origin using st_translate in postgis

How do I create a point 1000 meters away from a reference point? The ST_Translate only supports geometry type. I also tried using ST_GeomFromText but that returns a unit and not in meters. Here is ...