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

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Why use a database when you can have all of your data in javascript/openlayers?

I have a really simple and basic question. First of all, I have to mention that I am pretty new to web applications and GIS. I am working on a web application using Openlayers, Postgresql/postGIS and ...
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11 views

Close linestring to linering in PostGis

is there a function which closes a linestring to a linering? I couldn't found such a function in the documentation. Thanks.
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Comparing and updating two large tables

I'm using CartoDB to sync the status from tables using a common ID on each one. The problem I found it's the tables are too large, over 29k rows. Here is the query I'm using and the gives me an ...
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39 views

Installing TIGER geocoder

I am trying to install the tiger geocoder for postGIS. I am using the 2.1 version of postGIS on Windows 7. I am using this set of instruction to do so. I am confused by what they mean be edit the ...
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Connection trouble GeoExt to Geoserver Layer

I'm so sorry for my english, it's not the best. I'm trying to modify my postgres geographic table with this code: Ext.onReady(function () { OpenLayers.ProxyHost = "proxy.ashx?url="; var ...
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How to convert a raster to lat/lon points

I am working with the tri.txt (terrain ruggedness index) file from this paper: http://diegopuga.org/data/rugged/ I've uploaded the raster data from the file into ArcMAP and now have it as a .tif ...
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73 views

one label for two-lane roads (osm, qgis, postgis)

I labeled my osm-lines-layer (PostGIS) with symbols for primary roads and motorways. While the symbols for the primary roads are well placed - with enough distance between each - the two-lane motorway ...
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44 views

Disconnect QGIS from database without closing the whole program

I'm making PostGIS queries to a GIS database from python and I'm using QGIS to visually check the results of my queries, but every time I want to run a new query I have to close QGIS because it keeps ...
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30 views

How to create a routable network with PGRouting

I have two sets of data Table A: Stations - contains postal code (which I can convert to lat/long), name and code. Table B: Connections - contains a possible list of connections including source, ...
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69 views

Similarity between two or more trajectories

I have the data of trucks (http://www.chorochronos.org/). This data are gps coordinates of multiple trajectories of trucks in Athens. I have to calculate the similarity between the trajetories, in ...
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2answers
57 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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27 views

OpenGeo: GeoExplorer cannot upload shapefiles into PostGIS

I have installed OpenGeo 4.1 on Ubuntu Linux 12.04 following the official instructions. I then followed the tutorial Load your data with GeoExplorer. I was able to zip and upload a few shapefiles. ...
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51 views

Query to get convex hull

Is the below query correct to get a convex hull shape: DATA "the_geom from (select ST_ConvexHull(ST_Collect(the_geom)) As the_geom FROM xyz) as foo using unique id using SRID=XXXX"
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22 views

Error in querying data

I have a mapserver file as below , I get blank page with no map executing this query: NAME var DATA xyz STATUS ON TYPE POINT DUMP TRUE ...
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47 views

Create a Shape file from Sql dump file

I am trying to map data by querying a table called xyz. I need to show the the_geom data on the map. I have below query in my mapserver .map file: DATA "the_geom from xyz using unique id using ...
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1answer
59 views

Order by geometry columns

I am wondering how it really works, I mean "order by" statement when it comes to geometry/geography columns in postgis/postgresql. Besides that really need a way gather rows from a table with a point ...
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21 views

at which location to run psql2shp command in linux [duplicate]

I have linux system which I have connected remotely and I am not able to use $psql2shp command in the command line. I went to /usr/local/pgsql/data to run the command but I was unable to run. I dont ...
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42 views

Rollback error when restoring SQL dump file in postgresql using PSQL console via Pgadmin

I am trying to restore a pg_dump SQL file into my postgresql database using PSQL console , where I typed the below command: \i 'c:/../path/to/sample.sql' when I run this I get an error saying ...
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2answers
66 views

Where to type pgsql2shp command

How to convert post gis database into shapefile, I found that I need to use pgsql2shp command on postgis database query , But how to use it and where to use it. Do I have to use it in the postgre sql ...
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1answer
34 views

How to populate geography point using ST_MakePoint(long, lat)

I have a table called customer_campaign, and there is an empty column geom(geography) in it. So I want to fill it up by using ST_MakePoint(long, lat) in PostGIS, lat and long are two columns in the ...
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35 views

Geoserver ( Java.exe ) cause server to run 100%

Our server runs at 100% CPU when using map services build on geoserver + postgresql I can not find anything in geoserver logs. It is Java.exe takes 100% CPU and because of that server can not do ...
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100 views

How to export streets in a certain area from one shapefile to a new shapefile?

I have a shapefile with the roads from Europe and I want to export in a new shapefile only the roads from Greece. I tried to delete the other roads but there are too many and I have no attribute to ...
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29 views

How can I strip out M values from a MULTIPOLYGON with PostGIS?

The title is self-explanatory. I wonder if there is a simple function like ST_Force2D for the M values?
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2answers
100 views

Split lines at intersection points

I've got some linestrings covering a road network, and need to split them at the crossroads. Does anybody have any idea on how to do it? I'm using QGIS 2.4, with a Postgis 2.1.3.
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34 views

Clustering the WGS84 point features (projection transformation aspects)

My question is quite trivial and was discussed many times before (like here) but in our case it has the confounding extra requirements... The list of sparsely distributed 2d point features is stored ...
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35 views

Performing equivalent of ArcGIS Identity_analysis (line with poly) using PostGIS?

I've got a section of arcpy code that I need to port PostGIS: Identity_analysis with the in_features being a line featureclass and the identity_features being a polygon featureclass. I'm primarily ...
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39 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
45 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
50 views

Positons from GPS lanes inside a polygon

i have a lot of lanes like the orange lanes at the below picture (latitude and longitude values). Now i need all values from each lane inside the red polygon. What is the easiest way to realize ...
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24 views

A Tool for Mapping Metropolitan Statistical Areas (MSAs) to Addresses

My and team and I ran a series of zip codes from addresses within our data set against MSA to Zip Code data found on The Census' website here. We found that a relatively high number of the addresses ...
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62 views

All map services display pink tiles

I have implemented mapserver in Ubuntu 14.04 with postgresql 9.3, postgis and imposm using GitHub tutorial. After completing the tutorial all map services display pink tiles not map info. i was not ...
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16 views

ArcGIS dissolve analysis output issues in geoserver wfs/ PostGIS

I have an ArcGIS dissolve analysis output (parcel data) that needs to be loaded on PostGIS and published as a wfs from geoserver. The issue is that the ArcGIS dissolve output shapefile, although can ...
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57 views

Intersection of a vector linestring and underlying DEM

Following is an screen-shot where ASTER DEM raster layer has been overlaid by a road linestring vector layer. I want to extract those DEM pixels which are lying exactly beneath the linestrings. I want ...
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37 views

A* pgRouting issue with x1,y1 and x2,y2 values

I am trying to use the A* algorithm in a topology I have made in PostgreSQL. I can fill the x1,y1 and x2,y2 the latitude/longitude, but I have read that the same version has problems with ...
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43 views

Bounding box of a set of MULTILINESTRINGs PostGIS

I have a PostGIS table with a geometry column (geom) and a type column. The geom column contains only MULTILINESTRINGs and the type column contains tags that tell me what each MULTILINESTRING ...
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35 views

How to get the tripoint of three or more polygons in PostGIS?

Assume that I have a column containing polygons. What is the SQL statement to get the list of points that three or more polygons touch with each other?
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70 views

QGIS WFS Error - Could not commit changes to layer

I have a PostGIS database being served by Geoserver. I can load the layers I want into QGIS no worries; however whenever I try to edit the layer I get this error message: Could not commit changes to ...
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10 views

Get a geometry point along a line from another point with distance using OGC SFSQL

I am wondering is that any quick OGC SFSQL function (or any other spatial query) which return a geometry point that: The point is x distance along a line from its A-End ? ps: I am using postgis 2.x
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47 views

Extract longitude latitude and radius from POSTGIS column

I have entered the circle in the Geometry type column (name=shape) in my POSTGIS as following: ST_Buffer(ST_MakePoint($longitude, $latitude)::geography, $radius)::geometry Then I extracted the ...
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202 views

Can PostGIS and QGIS provide dependable multi-user editing?

After considering a few options, I'm trying to give my 15-20 QGIS 2.2 users the ability to concurrently view/edit one or two basic point PostGIS layers, largest one has just 16,000 records. I've ...
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37 views

QGIS There isn't entry in geometry_columns!

In PostgreSQL v9.3 with PostGIS v2.1 extensions I created a view from two tables (sites & visits). The site table contained a point geometry column (the_geom), which was included in the created ...
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29 views

Find correct SRID

I'm learning PostGIS raster, and importing GeoTiff with raster2pgsql. This command line tool states: -s <srid> Set the raster's SRID. Defaults to 0. If SRID not provided or is 0, ...
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Point sampling along a pole-wrapping coastline with PostGIS

I am working on a task that requires me to get sample points every 1000KM along coastlines, and have run into a problem with Antarctica. From what I can tell, it seems to be an issue with the use of ...
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1answer
42 views

Why does the earth drop off faster than expected over a geodesic when converting from lat/lon to cartesian coordinates?

In PostGIS 2.1.1, I've been plotting elevations from a raster over distances, but noticed that beyond 1km, the earth's curvature seems to be greatly exaggerated. In this example over a 40km geodesic ...
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50 views

Building web application to get PostGIS query from user and view result map using GeoServer via OpenLayers?

I'm a newbie in web-map application area. I just found the small application in this tutorial interesting I am a bit confused, because when i publish a map using geoserver and openlayer, I have to ...
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1answer
51 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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33 views

Ubuntu QGIS 2.4.0 SSL connection to remote PostGIS fails b/c can't specify certificates

I can connect with SSL in PGAdmin to my remote server, but it requires specifying the filepaths for certificate files due to my having different certs for different servers. However, when connecting ...
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2answers
352 views

Using ArcGIS and QGIS together in multi-user editing environment?

We have a GIS staff of 7, and another group of about 14 who "use GIS" from time to time. We really, really want multi-user editing. Mostly of a large point file, and we're almost never in the same ...
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72 views

How can I extract all distinct values from a PostGIS Raster?

I am working with an integer raster in PostGIS 2.1 and I would like to extract all distinct values in that raster. I was hoping to be able to do something along the lines of the following query, but I ...
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List of vector to one raster in PostGIS

Hi PostGIS developers! I need to rasterize a part of OSM map by coordinates. I found rather good algorithm, but can’t finish it. I have problems in STEP 3. I described all algorithm here – may be ...