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

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Installing postgis on postgresql 9.1 not working

I'm trying to install Postgis 2.0 on a perfectly functionig postgresql 9.1.10 database. I installed the package via: richard@srv1:/$ sudo apt-get install postgresql-9.1-postgis postgis Reading ...
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1answer
1k views

PostGIS Dissolve/Union close polygons

I have approximately 1 million polygons that have been split by lines. However, this has caused one half of a polygon to be separated by approximately 50cm from its other half. After doing a lot of ...
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1answer
721 views

Importing grib, grib2, netcdf to PostGIS

According to grib2 to raster? (grib2 -> raster2pgsql -> PostGIS 2.0 -> GeoServer), it seems like that grib2 can be treated as raster directly. Is it the so called "standard" way? How about ...
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3answers
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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 ...
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1answer
1k views

How to find polygons inside polygon with PostGIS 2.0

I have a relation representing all the counties in my country and the other one containing all the districts - e. g. each and every county is composed of several districts. How do I select them with ...
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2answers
393 views

small difference in projection between tilemill and postgis

I would like to create a world map with interaction on continents created directly from a postgis database. For the moment, I have a POSTgis database with the data. I created a background with ...
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2answers
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Select Duplicate Points PostGIS

I have a table made of merged point datasets in PostGIS. I want to select all of the features where two or more points have identical geom values. At present I just want to select so I can review ...
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1answer
4k views

How to filter features in a layer?

I am trying to display certain features in a shapefile-based layer using QGIS. I have found the subset function in the properties panel, which does exactly what i want, but is too tedious given that I ...
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1answer
3k views

How to get the coordinate system from a PostGIS database?

My question is probably amazinlgy stupid, but I can't find the answer myself. I would like to extract from a database the latitude and longitude of points. For now, I'm getting x(the_geom) and ...
2
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1answer
195 views

PostgreSQL default values in QGIS 2.8.1

I have a problem with default values the are set in a PostgreSQL table. When I work on them in QGIS 2.8.1 and I save the layer, the default values were not computed, so the constraints block me. With ...
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1answer
303 views

postgis: cluster/group points based on distance

We have a set of thousands of points and want to group all of those which are within 100m distance from each other (to get the centroid from each group). A first idea was to build 100m buffers around ...
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1answer
67 views

Coloring multilinestringzm M values in QGIS

I have output from a geophysical technique that produces X,Y,Z and scalar value for millions of points, which have been stitched together appropriately (by networkx if it matters) into ...
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Geoserver : create a rasterized polygon / dynamic fill for polygons with features from database

I decided to post here because I couldn't find any answer to my problems on the internet. So I am using geoserver 2.7-SNAPSHOT, everything is working fine but I need to implement a new function or ...
2
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1answer
92 views

PostGIS GML round trip confusion

I've investigated the issue of coordinate order in GML and each time I think I've got it but I find my self confused once again. I think some of my confusion may be to do with PostGIS. Doing a ...
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1answer
83 views

QGIS select reversed geometries

I have a road network and a geometry for each road direction. One Geometry from A->B and another Geometry from B->A. This geometries are covering each other. Is there a tool available in QGIS to ...
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77 views

Rebuilding a Polygon from the points within it, in PostGIS

This question is an update on the problem formulated here. I wanted to redefine the border of a set of polygons, in order to "smooth it". My first approach (described in the former question) was to ...
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1answer
76 views

Redefining the border of a polygon in Postgis

I have a PostGIS algorithm that writes a table with "pixelated" polygons, that I will call "clusters". My idea is to smooth the edges of these clusters using concave hulls (ST_ConcaveHull). To do ...
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1answer
117 views

Databases supporting intersection of multipolygons and a set of points

Currently we use PostGIS to store thousands of MULTIPOLYGONs and we can then use ST_Intersects to return any that rows contain any point in an input collection of points. Are there any other open ...
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1answer
123 views

PostGIS - How do I create a line that directly connects two earth points without travelling over a geodesic?

In PostGIS 2.1.1, I've noticed that if I create two distant earth points with equal altitude and then create a line connecting them, as I gather interpolated Z coordinate data along the line my Z ...
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1answer
107 views

SDO_Inside equivalent in PostGIS for 3D objects

I am looking for a solution for querying a point whether it is located inside a 3D object or not. If the point is located on the surface of 3D, I could use ST_3DIntersects or ST_3DIntersection. But, ...
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1answer
190 views

Spatial joining syntax

A standard PostGIS point-in-polygon query might look like this. (example tutorial) SELECT p.*,b.polyname FROM points p, shapes s WHERE ST_Within(p.the_geom,s.the_geom) Imagine this was not a ...
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1answer
329 views

How to calculate the shortest distance for multiple source and targets using PgRouting?

I have a table with points and a road network which includes driveways (where you enter the highway). I want to find the point which is closest to a driveway. So I was thinking I can calculate the ...
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1answer
306 views

How to generate pgrouting source and target with OSM?

Is there anyone here can explain me more details for pgrouting's source and target? I'm wondering how to generate with the given lonlat in OSM PostGIS entities. In pgrouting's website, they are ...
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1answer
333 views

Empty geometries in GEOMETRYCOLLECTION

I just noticed some strange behavior in PostGIS, with respect to WKT parsing. A GeometryCollection containing 1 or more empty geometries postgis_test=# SELECT ...
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2answers
172 views

Does PostGIS have separate implementation of GiST index from PostgreSQL?

I want to know if PostGIS has a separate implementation of GIST index or it reuses the GIST index implementation provided by Postgresql?
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1answer
234 views

Why is the QGIS 2.2 database tab missing?

I have recently installed QGIS-2.2.0 but the Database tab in the top-menu bar is missing. It looks the main reason is missing libgdal1h library. But when I am installing it, it's removing ...
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1answer
669 views

PostgreSQL : finding all lines intersecting with a polygon

I am totally new in the world of GIS but as a student surveyor I am working on a project using postgreSQL and PostGIS. I have one database with all the roads of my country (lines), and one database ...
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1answer
171 views

When would a PostGIS geometry compare using ~= return true when ST_Equals returns false?

I have a couple of featureclasses in a 10.2 geodatabase/PostgreSQL 9.2.2 database and I've been struggling with the FeatureCompare tool--it is telling me geometries are different on some features ...
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4answers
194 views

Linking up GPS points taken from rail network

Bit of a newbie here, trying to work out whether any PostGIS functions can help with my task. Apologies in advance if my use of GIS terminology is not up to scratch yet. I have a large database of ...
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1answer
87 views

PostGIS: How to understand ST_RasterToWorldCoord() right? (PostGIS 2.0)

After putting raster in to postGIS by this Thank @Sorin for helping me out! Now, I want to output raster tile, then view it on QGIS. But the problem is the output of ST_RasterToWorldCoord(raster ...
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1answer
139 views

How to change table name of command raster2pgsql

I am completely newbie with GIS and PostGIS as well I'm trying to load raster into postgreSQL with raster2pgsql. It runs well. However, the table name of the raster is generated automatically. For ...
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1answer
439 views

GeoWebCache seed task dies immediately after being submitted

The data comes from Geofabrik's Brazil slice: http://download.geofabrik.de/south-america/brazil.html Imported into a PostGIS DB with osm2pgsql. GeoServer is 2.4.0, running on latest Tomcat 7.0.x, on ...
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2answers
382 views

ST_ShortestLine gives different results for 4326 and 900913 projections. Which is correct?

I'm trying to get my head around how ST_ShortestLine (and ST_Distance and ST_LineLocatePoint) work with different projections. The result for the shortest line differs depending on which projection I ...
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1answer
1k views

GeoTools and PostGIS with ESPG:3857

I'm trying to use both PostGIS and GeoTools with the same ESPG:3857 projection, however, it looks like the projections in PostGIS and GeoTools differ. This is what I have in PostGIS: PROJCS["WGS 84 ...
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3answers
913 views

Why can't I open postgis layers in QGIS?

I've set up a table in PostGIS using OSM data (converted using osm2pgsql). I know this database is good, because I'm able to import it and work with it in TileMill, but whenever I try to interact with ...
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1answer
391 views

Raster Tile Merge Performance of PostGIS 2.0

I'm attempting to intersect Australian Census boundary polygons with the 1" SRTM DEM (10.5bn points across Australia), and output the result as a single raster image on the fly. The DEM is stored in ...
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2answers
477 views

Can Geoserver return the raster value of a lat/lon point

I have a GeoTIFF published by Geoserver 2.2 and being used by Leaflet via WMS. How can I get Geoserver to return the raster value at a lat/long point? I'm guessing it has to do with using WCS, but ...
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2answers
1k views

KML from EPSG:4326 to EPSG:900913

im trying to create KML files manually (XML format) by extracting data from a postGIS database with "geography" values in a column. But i belive i need to transform the projection of each row in the ...
2
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1answer
744 views

Getting points within a range from a postgres database?

ok so this is query i'm making which returns no result: SELECT building.gid FROM building WHERE ST_Dwithin(building.geom, ST_GeomFromText('POINT(long lat)',4326), 400) If I run this ...
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0answers
679 views

why preview image is blank for ImageMosaicJDBC (postgis raster) layer?

I follow http://docs.geotools.org/latest/userguide/library/coverage/pgraster.html to publish a ImageMosaicJDBC layer in geoserver. the layer seems published ok and saved, but the preview of this layer ...
2
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1answer
960 views

How can I fix QGIS PostGIS Manager error 'shp2pgsql' is not recognized?

I have QGIS 1.8.0 installed via OSGeo Installer and work on win 7. All I need is to upload the shapefile to the database via this plugin. Unfortunately I am receiving an error: Something's wrong: ...
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0answers
294 views

From pgRouting shortest_path back to osm node id

I'm successfully performing path finding queries like shortest_path on data imported with osm2pgrouting. The tables I have inside my pgrouting DB are the following: List of relations ...
2
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1answer
500 views

Querying PostGIS Raster with MultiPoint

For one of my projects using PostGIS 2 I have a table with GPS tracks (igc_files). It holds records including a MULTIPOINT() column that has about 1,000 points for each record and a column that has an ...
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3answers
1k views

adding non spatial attributes using geoserver

I am using Openlayers + geoext to perform transaction operations in postgis database using geoserver . i can insert spatial data into postgis but cannot insert other data like road name, road type in ...
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1answer
577 views

Accessing PostGIS raster data using Query Layer in ArcGIS Desktop?

I tried to load raster file (jpg) into post gis using the syntax provided here "C:\Program Files (x86)\PostgreSQL\9.1\bin>raster2pgsql -I -C -e -Y -F -s 102003 -t 300x300 ras_test.tif ras_test1 | psql ...
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2answers
3k views

Problem when calculating longitude and latitude for points

I have a PostGIS database with SRID=900913 (Google Mercator) and I would like to know the latitude and longitude of points. I use this command: ST_X(ST_TRANSFORM(the_geom,4283)) Following what is ...
2
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1answer
567 views

The minimum bounding circle of geometry that crosses the 180th meridian

Background: I've been given a task where I have to calculate the minimum bounding circle of Alaska (for the purpose of running a Roeck test). I'm using the Census' state level geometries available ...
2
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1answer
3k views

Basic MapServer query of PostgreSQL/PostGIS database

I've just installed MapServer on a linux server and I am trying to understand how to display a basic map using a PostGIS database. I have displayed a shapefile in the browser, so I know that the ...
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2answers
494 views

unable to call shp2pgsql using python

I am unable to call shp2pgsql using python as I have to pass various options like (-s -a -i) and I am not getting the required output .. Method I am using is p1 = subprocess.Popen(["cmd", "/C", ...
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1answer
1k views

GeoServer converting PostGIS timestamp with time zone

In a PostGIS view i have a field of data type "timestamp with time zone". In GeoServer this field is show with datatype "Timestamp" My problem is that i want the Timestamp to be show in my ...