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

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2answers
119 views

What is wrong with how I am using ST_Within?

I am learning postgis 2.1. I created a postgis table from a shapefile and imported it into the DB. It made a table like this: db=# \d districts ... geog | ...
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2answers
180 views

can't geocode with PostGIS 2.1.1

I don't know where's the mistake... I am using the process from the PostGIS documentation (http://postgis.net/docs/manual-2.1/postgis_installation.html#loading_extras_tiger_geocoder) . I created a ...
3
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2answers
184 views

ESRI projection to SRID?

I am looking at MapX and MapY coordinates. The docs say they are "truncated State Plane coordinates: NAD 1983 State Plane Louisiana South FIPS 1702 (US Feet)." I am trying to reproject into a common ...
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0answers
34 views

Double version of PostGIS installed on my server

For some reason I messed up an installation of Postgis on my PostgreSQL 9.2.8 server. I had version 2.0.3 installed and when I tried to upgrade to 2.1 it did so. The problem comes when I dump the ...
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0answers
257 views

PostGIS 2.1 error install with shared object (rtpostgis-2.1.so") Linux Mint

I've Installed Linux Mint 16 mate and install PostGIS with PostGreSQL (I've tried many ways in the Internet from original source to some suggestion) but all is too error: " ERROR: could not load ...
2
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0answers
58 views

PostGIS does not export shortest path to Shapefile

I am trying to draw a bunch of lines overlaying the globe map in a WGS84 projection. To this effect I have created a PostGIS DB with a table that has one column containing linestring data. My problem ...
0
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2answers
926 views

How to install PostGIS and OpenLayers plugins?

I am new to QGIS and have installed the QGIS v 2.2.0. For adding google map as a base layer I need to install OpenLayers plugin. I also need to add the PostGIS plugin for DB management purpose. Can ...
2
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1answer
188 views

POSTGIS: function st_collect(geography) does not exist

I am trying to use some Geography functions, but I am getting an error that (all) functions are not existing. I have checked other Stackexchange posts (e.g. this one), but the solutions did not work ...
3
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2answers
80 views

How <-> operator work?

I'm doing a search to find links close to a point. The problem is if i limit to 20 result i found the closer link at 6mts but if i limit to 10 result that link doesnt appear and the closest link is ...
2
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1answer
66 views

Can you do ST_Transform on geographies?

I am brand new to postgis. I just learned that geometries model simple cartesian objects and that geographies model shapes on the surface of the earth. I have a bunch of data in columns X and Y of a ...
3
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2answers
286 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 ...
1
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1answer
30 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? ...
2
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0answers
31 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 ...
0
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2answers
69 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 ...
1
vote
1answer
181 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 ...
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0answers
32 views

PostGIS : check if 2 lines are at contrary sides of third line

I am looking for a workflow to select a line on the condition that it is located on the contrary side of a middle line. So there are 3 lines (2 are given, 1 I want to select). I don't need you guys ...
3
votes
1answer
76 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
169 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
67 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 ...
1
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1answer
64 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
votes
1answer
119 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
100 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
112 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
108 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' ...
0
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1answer
67 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 ...
1
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1answer
219 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 ...
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2answers
227 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
109 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 ...
0
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1answer
80 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
votes
1answer
103 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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0answers
51 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
53 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, ...
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2answers
84 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
votes
1answer
160 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 ...
3
votes
1answer
190 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
32 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, ...
1
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1answer
78 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 ...
1
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1answer
411 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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30 views

Multiple Centroids within a dataset based on distance

Is there a way that we can find out the centroids of clusters within a dataset while differentiating one cluster from other based on distance not on any attribute value. The dataset is present in ...
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0answers
84 views

Postgis performance: st_dwithin vs static buffer and st_contains

I have a table with a polyline column. I need to find which of those polylines are within 20 meters from a bunch of moving points. I can do this no problem with st_dwithin(). What I would like to know ...
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0answers
271 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
votes
2answers
196 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 ...
4
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3answers
327 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: ...
0
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0answers
84 views

QGIS - Loading data by SQL-window in the DB-Manager is not working?

I have problems to add a subset from a PostGIS-table to QGIS by using 'load as new layer' in the SQL-window of the DB-Manager (QGIS-Version 2.2.0-Valmiera). I defined both the 'column with integer ...
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0answers
51 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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0answers
76 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: ...
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2answers
47 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 ...
2
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1answer
93 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
votes
1answer
104 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
264 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 ...