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

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Get the lines between all points of a polygon in PostGis : avoid nested loop?

I am trying to get all the lines between the points of a polygon, by writing PostGreSQL functions. I have written the two following functions that do the job fine : the first function to get all the ...
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1answer
329 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 ...
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1answer
2k views

Extract lat, lon Points from Polygon

I have PostGIS database, and want to extract lat, lon pairs sequence from Polygons (and MultiPolygons). As a very fresh PostGIS user, I'm able to just extract the Polygons: SELECT st_astext("GEOMETRY"...
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700 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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677 views

overlay my shapefiles stored in database to the web/browser [duplicate]

I am very much strrugling on how to display my shapefiles stored in postgis database to the browser or to the web.. is there anyone there knows how to do it.? I am using geodjango framework in python,....
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Growing a PostGIS geometry by a percentage

I'm looking for a way to add a buffer around a PostGIS geometry, but the size of the buffer should depend on size of the geometry. That is, I want each geometry to be enlargened by, say, 5%. The idea ...
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3answers
2k views

getting dxf files out of PostgreSQL

I've successfully loaded a bunch of shapefiles into a PostGIS database. I would like to be able to retrieve specific geometry and layers as dxf files based on SQL queries. I'm using PostGIS, GDAL, ...
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2k views

What is difference between ST_DWithin and ST_Distance for proximity search in PostGIS?

I have records stored in a table with latitude/longitude coordinates stored in a geometry field. I want to find all records nearby a user supplied reference point. Note "nearby" probably means less ...
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5k views

PostGIS ST_Buffer Radius Help

I am trying to find all points within a five-mile radius of a given point. I have a query like this: SELECT * FROM table WHERE ST_Contains(ST_Buffer(geomFromText('POINT(0 0)', 4326), ?), latlon) I ...
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850 views

How to replicate ArcGIS Intersect in PostGIS

I'm trying to replicate this ArcGIS process in PostGIS: http://blogs.esri.com/esri/arcgis/2012/11/13/spaghetti_and_meatballs/. This describes how to break buffered points down into polygons based on ...
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3answers
4k views

When should I use ST_Buffer?

I would like to know what is the sense of using st_buffer operation. In PostGIS reference guide there is only the syntax and a short description of this operation. Could you give some examples to ...
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3k views

How do I perform a proximity search with Postgis?

OK, so I downloaded the Geonames database (cities1000) and wrote a small Ruby program to import them into my table (geo_cities). I then added geography column called geog. So after all of that, I ...
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2answers
12k views

How to connect OpenLayers to PostGIS data?

I have read in OpenLayers how to load KML, GeoJSON etc. vector files in OpenLayers. But how can I connect to PostGIS data. If not, why should I upload my data to PostGIS then instead of directly ...
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2answers
9k views

Exporting shapefile to PostGIS database in QGIS

How do I export a vector shapefile to PostGIS database? I am asking what format I have to export it.
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2answers
5k views

How to add Geoserver WFS to Leaflet JS Application

I have a PostGIS database and have successfully consumed a table into GeoServer and published a WFS. Are there REST endpoints available for these WFS' akin to ESRI's feature services? How are ...
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1answer
1k views

Split edges at intersections in PostGIS

I'm attempting to do a walking distance analysis using OpenStreetMap data (osm2pgrouting) and PostGIS and following underdark's blog posts, however I need to exclude residential and service roads that ...
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1answer
286 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 ...
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3answers
1k views

Convert KML to shapefile without losing attribute data

So I want to convert KML files to SHP shapefiles to load it onto PostGIS. Currently I'm using ogr2ogr to do the conversion for me, but it wipes out all the attribute data. How do i preserve this ...
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1answer
349 views

Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
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2answers
496 views

Extract PostGIS line features to GPX

I have a request to provide GPX files of certain trails (around 100) that are present in OpenStreetMap. Given a local PostGIS install with OSM data, I think the process would be something like: ...
3
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1answer
521 views

ST_Equals Postgis problems

I am trying to find overlapping lines using ST_EQUALS on two tables This query returns 0 rows: SELECT * FROM geom1 c, geom2 h WHERE st_equals(c.simple_geom, h.simple_geom); This query runs ...
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1answer
1k views

How to split line layer at polygons' boundary of a polygon layer?

I have a line layer and a polygon layer in PostgreSQL 9.2, PostGIS 2.0. How can I split every line each time it crosses a polygon's boundary?
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1answer
3k views

Why does ST_Transform fail?

I got a postGIS error like this, ERROR: transform: couldn't project point (100.496 13.7118 0): latitude or longitude exceeded limits (-14) SELECT ST_Length(ST_Transform(ST_GeomFromText(E'LINESTRING(...
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2answers
255 views

How to create more networking osm

Using localhost page generated by osm2po roteamente noticed that the link is made to link even disabling snapping. Logically thought to create more nodes in the network, but how can I do this ...
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234 views

How to union polygons and add attribute values of combined output features

I have a layer containing 10 polygons all overlapping at various locations. Each polygon has a value of '1' in a column called "value" How do I Union the polygons (rows) together such that the ...
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427 views

Help defining custom CRS in QGIS 2.2

I'm trying to use EPSG:4479 in QGIS. 1) If I search for EPSG:4479, it returns a "Imported from GDAL" EPSG:4479, but it does not work. At the console, the following message is displayed: ERROR 6: ...
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846 views

take from multilinestring the start & end points

I have to use the A* algorithm and my geometry is in multilinestring and i want to take stratpoint(x1,y1) and endpoint(x2,y2) . I use this queries but the colums after the execute is still empty ...
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575 views

Automatic bulk snapping with FOSS

I'm looking for a tool that would be able to automatically snap features closer than a given distance. Is there such a tool/plugin for QGIS/GRASS/OpenJump? Would it be possible to achieve that with ...
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602 views

In what situations would SpatiaLite be selected over PostGIS, and vice versa?

I know that SpatiaLite is a lightweight solution. Would it be a problem if I put it on a 5K pageview/day site? Is PostGIS too resources-consuming for such usage? The dataset is something like < ...
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3answers
744 views

Import shapefiles on my postgis table using R

Using R, I would like to import shapefiles that are in a directory on a geometric table i have on postgresql / postgis. What is the instruction that allows me to do it? EDIT: here is my code to ...
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3answers
2k 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 ...
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397 views

Calculating path sinuosity in postgis

Sinuosity is a fairly straightforward concept. How can this be calculated in postgis given a series of linestrings that represent the path?
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SQL Syntax to extract (convert) Strings with Degrees Minutes to Decimal Degrees

I have a PostgreSQL/PostGIS database with a two string fields containing Lat and Long coordinates in degrees and decimal minutes, like this 45° 24.5' N 3° 43.01' E. How can I convert them into ...
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1answer
7k 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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3answers
562 views

How to efficiently find points within an elliptical area?

Using PostGIS 2.0.0 I need to filter the results of a function, which returns many POINTs, to find the ones that lie within an elliptical area defined by two points and a distance (all parameters ...
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739 views

How can I properly add PostGIS data into MapGuide Maestro?

I am having trouble connecting a PostGIS database to MapGuide Maestro. Actually, I have added the PostGIS data into Maestro, but when I click to validate the layer it shows an error message: ...
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1answer
960 views

Visualising a raster PostgreSQL table in QGIS

I have imported a raster tif image into PostgreSQL with this command: raster2pgsql -s 32643 -I -M filepath.tif -F -t 100x100 public.databassename > filepath.sql And imported the output SQL file ...
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1answer
140 views

Create common vertexes between shared polygon boundaries in PostGis?

Given two polygon tables L1 (blue) and L2 (red) that share a common boundary but different amount of vertexes, how can one make the shared boundary identical (they should share the same vertexes) ? ...
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694 views

Editing PostGIS data in ArcGIS Desktop?

Quick question regarding editing PostGIS data in ArcMap 10.0. Far as I can tell, this can only be accomplished through third-party plugins like GISSquirrel or ST-Links. Does anyone know of an ...
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2answers
690 views

How to enable SFCGAL in PostGIS?

I have the problem with the enabling extension SFCGAL. CREATE EXTENSION postgis_sfcgal; doesn't work for me even I have the PostGIS v2.2. When I do that, it throws an error ERROR: could not ...
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3answers
230 views

How can I draw squares in PostGIS layers at different angles?

I am trying to draw two squares on a 45-degree angle and then merge them using PostGIS to edit. QGIS can draw squares but only on a perpendicular plane (eg, 0, 90, 180), and I need to be able to draw ...
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2answers
4k views

Postgis installation error

I am using fedora machine. I want to install postgis on my system. So this is what I have done Installed Postgresql and supporting packages using YUM. Created directory /sources to put all the ...
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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 ...
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1answer
524 views

How do I get the closest point on a road to a point when I have imported OSM data using osm2pgsql?

I have been trying to use OSM data to find the closest point to a road for a given point. I imported the OSM data into postgis using osm2pgsql, and I am getting results back, but they are at the ...
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2answers
1k views

DatabaseError: Coordinate values are out of range [-180 -90, 180 90] for GEOGRAHY type

I am using Django 1.3, PostGIS 2.0 , Postgresql 9.0 and GeoDjango. I had a database with a table for places. This table had latitude and longitude for places in the US. I enabled this database with ...
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1answer
214 views

Automated correction of parcel geometry based on area measure?

i have a set of parcels in DWG file and i have the areas that should be in these parcels in an excel file, so i have to modify each parcel to match the area specified in the excel file with a moving ...
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88 views

QGIS does not display all Features of Layer and behaves weird instead

I have a weird problem with QGIS trying to load a Layer from a Postgis Database When I open the Layer from Postsgis I have two choices: Method one: Either, I use the Panel "Browser", where I can ...
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1answer
404 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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2answers
94 views

Separating Overlapping DMAs by State using PostGIS?

I have two shapefiles. One is the DMA and another of states I know that some DMAs, such as Chicago will overlap between multiple states, for instance the Denver DMA overlaps states outside of CO and ...
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1answer
1k views

Why does my PostGIS query fail with “current transaction is aborted”

I'm trying to create a vector layer in a QGIS project using a PostGIS query. QGIS is returning the following error: Query failed 1 cursor states lost. SQL: CLOSE qgisf1 Result: 7 (ERROR: ...