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

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572 views

How can I GROUP BY linear spatial clusters with PostGIS?

I have a series of points in a horizontal line, arranged into discrete spatial clusters by the underlying data pattern. Here's an example of what they look like: How can I use PostGIS to group them ...
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1answer
47 views

Does the psql prompt have a working directory in the file system?

I am learning postgis. This tutorial says "Navigate to where you downloaded the shapefile." Does that mean navigate to this location in the #psql prompt or navigate to this location with the $propmt? ...
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32 views

PostgreSQL : Question about dropping tables inside funtions

I am writing a PostgreSQL code where I have a function wich is used multiple times in a single query with different input values. Inside the function I create some tables and use them. What is the ...
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2answers
132 views

ST_NumInteriorRings not returns zero, is a bug?

I am using PostGIS v2.0.3, the guide say that ST_NumInteriorRings "will work with both POLYGON and MULTIPOLYGON types but only looks at the first polygon. Return NULL if there is no polygon in the ...
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1answer
658 views

PostGIS Type Modifier Error

I'm trying to work an example from the "PostGIS Cookbook" and I'm getting an error I don't understand. I'm running the example using Postgres.app on a MacBook. Postgres.app is running PostgreSQL 9.1....
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1answer
432 views

PostGIS create read only user for QGIS

I am having issues reading spatial tables in QGIS with a select-only "reader" user. I can create the reader user to access regular postgres tables like this: GRANT USAGE ON SCHEMA test TO reader; ...
4
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2answers
466 views

How to speed up a query for nearest linestring to point data

I have processed a Strahler stream order layer with a lot of river linestrings (type: Multilinestring) and their corresponding strahler number (see information here). Besides I have a point layer. I ...
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0answers
109 views

Do ArcGIS clients that direct-connect to postgresql/postgis databases override configuration settings?

I went in to modify some settings on a Postgresql database via the PGAdmin config editor and some of the settings don't have their default values and they are higher because they've been overridden (e....
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1answer
130 views

Osm2pgsql crashed on import. Can I continue with what has been imported so far?

I recently imported the osm planet file using osm2pgsql. The process crashed (hung my whole box) when creating the geometry indices and other indices on the tables. Scouring through the source code, ...
2
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1answer
298 views

PostGIS : I want to use ST_OffsetCurve with MultiLineStrings

I need to use the function ST_OffsetCurve for a multilinestring, but PostgreSQL gives me the error that the function is only for Linestrings. Is there a way arround? I want to use the function ...
3
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1answer
389 views

polygon from exterior points

How to convert points data to polygon, so as to form polygon from exterior point as shown above
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2answers
868 views

pgAdmin vs psql

I have downloaded postgreSQl 9.3 and Postgis 2.1 recently as an educational adventure and have been working with both through the pgAdminIII interface. I haven't used psql yet when working with my ...
2
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1answer
326 views

Update postgres/postgis point data attribute from another enclosed polygon shapefile in QGIS

I have a placename point table in postgis with 'district' column. a districts polygon shapefile with district name in 'Name' column. See the image below. I would like to update the 'district' ...
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1answer
101 views

Polygon feature in PostGIS

I have uploaded a feature to the PostGIS db and visualize it by mapguide. Now I would like to know how can I update (add) features from database directly. Can I add a new row from the web form ...
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1answer
745 views

Converting lat-lon from degrees and decimal minutes to decimal degrees in PostGIS [duplicate]

Creating a geometry in Postgis is fairly simple: ST_SetSRID(ST_MakePoint(longitude,latitude),4326); These lat/lon should be in decimal degrees format like 33.02505 -96.70668 Is there a way/...
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2answers
712 views

GeoServer create layer from PostGIS (data type point)

(Several days ago a user on gis stackexchange suggest that I should use OpenGeo (I was using geojson before). I succeed at what I was doing at that time, but now I have a different problem.) I was ...
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0answers
468 views

Broken PostGIS support GDAL

I'm having some problems with Postgres/PostGIS after rebuilding my GDAL library:( I wanted to add MrSID support in GDAL so rebuilt it with the MrSID SDK. Everything compiled ok and I am now able to ...
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1answer
314 views

Connecting to PostGIS (LATIN1) from Microsoft Access 2010 - Encoding problem?

I want to connect to a PostGIS table Using MS Access. The table has been created using the PostGIS Shapefile loader in pgAdmin. It has been encoded at LATIN1 (it wouldn't load with UTF-8 default). I ...
2
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1answer
251 views

Problem with matching a buffer in Openlayers and the same buffer in PostGIS query

I am using a buffer tool to create a buffer on my base map in Openlayers. In addition to creating and visualizing this buffer, I pass the center point and radius to a query. The query collects all ...
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1answer
151 views

How to define Z dimension on table with PostGIS for import in TileMill?

I'm trying to reproduce the idea behind this blogpost from Mapbox, but with other data, for example the ne_10m_populated_places_simple dataset from Natural Earth. By adding a z-dimension to the data (...
2
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1answer
205 views

ST_ZMax() does not exist in PostGIS

I'm trying to follow this example on Mapbox blog, about using 3D shapes in PostGIS. The database-query is this: DROP TABLE tilemill_buildings; CREATE TABLE tilemill_buildings AS SELECT ogc_fid, CAST(...
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2answers
173 views

Suggest an algorithm to measure how a node is connected to road network

I try to measure how well a node is connected to the rest of the network. If a city has a distant suburb connected with one sole road, it's connectedness is, say 1. If it's connected by 2 roads, it's ...
3
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1answer
650 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 ...
4
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1answer
626 views

How to create a buffer on a linestring with varying or increasing/decreasing width

I want to buffer rivers/streams for a topographic map. I'm using a PostgreSQL/PostGIS database. Usually, I create buffer with ST_Buffer with a constant width. For example, the width of a river buffer ...
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0answers
86 views

How to SELECT one day's scene (Landsat 8 scenes)

I have a huge dataset of raster in PostGIS. Each scene is divided into tiles (tile-size 500x500). I was trying to SELECT rast FROM landsat8 WHERE ST_Intersects(rast, polygon). It runs very slow, ...
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1answer
202 views

OpenLayers WFS no FID being passed from TinyOWS

I have a webapp - OpenLayers<->tinyows<->postgis. With 1 layer I have a problem. On localhost all works well - here is a snip of the XML I get back: <gml:featureMember> <tows:trad ...
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1answer
3k views

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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1answer
577 views

QGIS loads PostGIS layers but DBManager can't connect

DB Manager can't connect to PostgreSQL, but "Add PostGIS Layer" can. My eventual goal is to save created layers to PostGIS. I assume I can do this using the DBManager Tool. I can alternatively use ...
2
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2answers
461 views

Export to Mapbox (TileMill) from PSD (or SVG/PNG)

Newbie question: I designed a map (not Earth-related) in Photoshop and I want to use something like Mapbox to serve the map and make it dynamic (bounding boxes, zoom in/out, etc). How can I go from an ...
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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53 views

Using PostGIS to find airplanes flying on the same routes over the sea [duplicate]

I need to answer the following questions: 1-Given a database of all flights,including flight ID and the airplanes location (lat/long etc) taken at timestamps of constant 1 minute intervals, find all ...
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193 views

Adding GIS feature into an existing postgis table using django 1.6

i am using Django 1.6 on my web map. the problem i got is that i cannot import shapefile with features about 200. . the console has given me this traceback. . Saved: 162-05-0001-005-31 Saved: 162-05-...
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2answers
57 views

How can I determine which polygons contain other polygons?

I am using only free, open source tools. I have two shape files: a shape file of voting precincts and a shape file of census tracts. I want to know: which voting precincts fit inside which census ...
3
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1answer
257 views

PostgreSQL : total length of roads in polygon

I have 2 tables : wgo (lines) and wbn (polygons) With this code, I can display the length of each road inside a polygon. If I have a polygon with 2 roads in it, as a result I get 2 rows with the 2 ...
2
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1answer
343 views

Area of polygon split by a line

I need a query that return the area of two polygons that have been split by a line. This is what I did so far: SELECT ST_Area(ST_Split(surface.geom, limite_a.geom)) from surface, limite_a where ...
2
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1answer
1k 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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2answers
232 views

Help with postgis on mapserver

just set up my mapserver on Ubuntu - all good. Downloaded this tutorial and it works fine: http://download.osgeo.org/mapserver/docs/mapserver-tutorial.zip I've tried adding a PostGIS layer to the map,...
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2answers
268 views

How to count points once with overlappying polygons?

All, We're using parcel data (polygon) to count student locations (point) based on parcel type. We're doing this using SQL and the ST_Intersects function. It works great, except the City and County ...
5
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2answers
830 views

Postgres Log Error

I am using Geoserver + GeoWebCache + Postgres for an application. On the application side there is no bugs but on postgres I am getting this log. Please explain and help me to solve this 2014-03-...
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2answers
206 views

PostGIS: ST_Clip() throws non-noded intersection between LINESTRING

I have a polygon and a set of rasters. I'm trying to clip raster with polygon. As you see, my rasters is divided into tiles. Any tiles that is contained by the polygon has ST_Overlaps(polygon, ...
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1answer
300 views

using postgis function in pyqgis

I'd use Postgis function in Pyqgis script. This code: qsql="(select gid, id, St_Buffer(the_geom,200) as geom from archi)" uri = QgsDataSourceURI() uri.setConnection("ip", "port", "x", "x", "x") uri....
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0answers
332 views

PyQGIS Dialog Plugin not resetting

I have written a PostGIS search plugin that works pretty well, except two things that I just cannot figure out a solution 1) When the dialog closes and then is reopened the previous query is still in ...
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3answers
254 views

Geometry vs geography for line-to-polygon intersection

I have two WGS84 NAD83 shapefiles, one polygonal, the other containing lines: Geometry: Polygon Feature Count: 1294 Extent: (-79.761059, 44.991143) - (-57.105486, 62.582865) Layer SRS WKT: GEOGCS["...
6
votes
3answers
4k views

PostGIS: parse geometry wkb with OGR

I'm trying to pull a LineString geometry out of PostGIS and parse it with OGR (python bindinds). from osgeo import ogr import psycopg2 connection = psycopg2.connect("...") cursor = connection.cursor(...
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2answers
292 views

How to obtain timestamp and user id from .osm file in PostGIS enabled Postgres database

At present, osm2pgsql seems to ignore the timestamp and user id of the elements, a serious drawback for some applications. According to a bug report this is not solved by the addition of the --extra-...
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0answers
456 views

How do I catch PostGIS/PostgreSQL RAISE messages in QGIS?

I have a trigger set up in PostGIS/PostgreSQL which will show a RAISE WARNING when an inserted or updated polygon is within a certain distance of some predefined planning constraints. I want this ...
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2answers
418 views

Switch coordinates in linestring

I made a silly mistake: when creating linestrings in my PostGis database i inverted the lon and lat values. Which isn't a problem for postgis itself, but for my visualization and intersections. ;) Of ...
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0answers
315 views

django---error in displaying data and displaying it on the map

. i am trying to display a feature queried from postgis. . i also designed a user input field to enter the id of the desired feature to be displayed. . i have already queried the attributes first ...
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1answer
198 views

PostGIS: ST_Clip() raster in SRID:32617 with a polygon

I'm trying to ST_Clip() raster in `SRID:32617' with a polygon. What I did ST_Transform(polygon, 32617): It fails, couldn't project point() exceeded limit (-14) ST_Transform(rast, 4326, '...
4
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1answer
833 views

PostGIS ST_Intersection of polygons can return lines

When clipping the polygons of one table with polygons in another, ST_Intersection can return a set of results that can be handled with ST_Dump. The returned multiple geometries are not necessarily ...