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

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3answers
896 views

How to speed up Postgis raster layer display in QGIS?

i've been importing some digital orthophoto geotif files into postgis 2.0.1 via raster2pgsql tool (i also made 3 levels of an overview table - pyramid). Then i tried to import the layer into qgis via ...
3
votes
1answer
2k views

convert list of points to line or polygon

I have a list of Points in a PostGIS table. The rows can be grouped by a date something like: myTable id INT date DATE lat NUMBER lng NUMBER geom GEOMETRY(POINT) now I need a table where all ...
3
votes
2answers
724 views

Merging polygons that intersect by more than a specified amount

I am working with a dataset that contains a subset of property boundaries in a local government area, thus my dataset is made up of several thousand properties but not all are touching. Since it is a ...
3
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1answer
2k views

PostGIS Error: type “geography” does not exist

I just upgraded my development machine to Windows 7 and am therefore reinstalling PostgreSQL and PostGIS. I used the Postgres Plus installer, as recommended on the Postgres website, and followed this ...
2
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1answer
205 views

Mapnik + OpenStreetMap + Shapefile with Raster Images + Mod Tile + PostGIS

I am new to GIS. I have a Shapefile (.shp, .shx and .pbf). The .pbf file contains path to PNG files located on my machine only. I was able to save the Shp data to PostGis via Shape2Gis tool. Now ...
2
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0answers
136 views

TileMill Exports Failing

I'm having trouble exporting my map in TileMill (v0.10.1). I'm using OSM Bright with a PostGIS database connection to import OpenStreetMap data. When exporting an SVG or PDF through the user interface ...
2
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1answer
97 views

PostGIS Raster: Outputting raster into GDAL supported file?

I have import a raster into my postGIS database via raster2pgsql. My raster tiled to 100x100. Now I'm trying to export (output) the raster to GDAL supported file (for example: PNG). Following the ...
2
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2answers
779 views

Install PostGIS and TIGER Data in Ubuntu 12.04

Could someone write a brief albeit dumbed down idiot's guide to installing postgis and loading national Tiger data on ubuntu? I've tried a few guides, namely, ...
2
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1answer
97 views

How to split polygons with another polygon and inheritage data?

Let's say that we have two tables with polygons representing areas. Table A and Table B. Geometries from table A represents both the valid and invalid areas. And the geometries in table B represents ...
2
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2answers
2k 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.
2
votes
1answer
56 views

Compare features in PostGIS with updating attributes

I have two polygonal layers: "existing" and "modified". Attribute table of "existing" and "modified" layers have same column "feature_id" - number of feature. Please help me create query which write ...
2
votes
1answer
304 views

How to merge connected lines with same direction (PostGis)

I am looking for a way to join all lines that are connected, have the same direction, i.e. start point of one is end point of the other, and share some common attributes. In fact, I want to connect ...
2
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1answer
352 views

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 ...
2
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2answers
1k views

What Spatial Reference System do I store Google Map's Lat/Lng in

I am new to PostGIS, Spatial Reference Systems and projections and want to store lat/lng coordinates retrieved from Google Maps and Openstreetmap and its services like the Geocoder/Nominatim. I'm ...
2
votes
2answers
526 views

Create CMS system using Cartaro

The main objective for our project is to create a portal website in Drupal. On this website, people must be able to upload their geographical datasets (mostly shape files, but also xml files that ...
2
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2answers
414 views

How fill length and feature count in PostGIS table for each polygons

I'am new to PostGIS/PostgreSql. I have a database which containts two shape-files : polygonal layer towns and linear layer of roads To calculate the length and feature count of 'Streets' inside ...
2
votes
1answer
564 views

How to debug 'Layer is not valid error' from Python plugin?

I'm trying to understand what goes wrong with a QGIS python plugin. Basically I'm trying to render a series of POINT. The query works fine, at least giving it by hand from inside PostGIS DB: "SELECT ...
2
votes
1answer
743 views

Access PostGIS Raster layer through mapserver

I am trying to use a cgi script calling mapserver to display a raster layer that is stored in a PostGIS database. However, only a blank white image is returned and I don't know where the problem is. ...
2
votes
1answer
521 views

How can I get the corners of a polygon in latitude and longitude?

How can I get the corners of a polygon -a square/rectangle, to be precise- in latitude-longitude format by using its geom value -or some other way, perhaps-? Thanks.
2
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1answer
858 views

geoserver wfs insert error

I keep getting an insert error from geoserver when trying to save a point, poly etc etc to my postgis table. any ideas, my code is below var Projection = new OpenLayers.Projection("EPSG:4326"); ...
2
votes
1answer
631 views

Routing Application in Windows

I am making an routing web application similar to Google Maps 'Get Direction' feature. But because of the limited control and data on GMaps, I decided to use OpenStreetMap instead. This also made me ...
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vote
1answer
92 views

Get a single cluster from cloud of points with specified maximum diameter in postgis

I have on the order of 2M Geometry Collections with N (median: 2, stddev: 6.6, 75th: 6, 95th: 21) Point objects (repeated points allowed and important) in a PostGIS table. I want to identify clusters ...
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1answer
101 views

Problem with using a circle as polygon for querying PostGIS

I'm trying to query PostGIS and find some object features that intersect with a circular buffer created by the user using OpenLayers, JavaScript and PHP. I use the following code for creating the ...
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vote
2answers
945 views

Attempting to use ST_DWithin to locate objects within a given distance of meters using SRID 4326

I'm a Rails developer with minimal GIS experience, working with PostGIS and the RGeo gem. I'd like to find all of the cows within 500 meters of my current location. So, I'll create a model for my ...
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vote
1answer
849 views

PostGIS, create line from points

I have a PostGIS table with position data of numerous vehicles and want to create lines from these points. Data can be selected by vehicle id and ordered by timestamp but how to create lines from the ...
1
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1answer
258 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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vote
5answers
2k views

Unable to install the PostGIS extension to PostgreSQL on Ubuntu 12.04 LTS

I just installed Linux Ubuntu 12.04 LTS (on a virtual machine). I then successfully installed the PostgreSQL 8.4 database management system. I am now trying to install PostGIS, which is an extension ...
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vote
1answer
482 views

From a trajectory of GPS points to a multiline segment

Given a trajectory as a sequence of GPS points I would like to create a smooth linestring representing a path where a car drove. The data is stored in postgresql: the input trajectory in a table, ...
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vote
1answer
682 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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2answers
2k views

mulitlinestring to linestring

I am using postgres with postgis and I have a set of points which I would like to interpolate with a set of lines. Now my problem is that the set of lines are of type multilinestring. Is there a ...
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2answers
1k views

How to find the nearest line from a point?

I have a table of Roads in PostGIS which geometry is "geometry(MultiLineString,4326)". Its attribute are gid osm_id name ref type oneway bridge maxspeed geom Now i want to know ...
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1answer
243 views

Howto setup osm2psql

I'm following these instructions to setup osm2psql . I need it to import osm data file inside a PostGIS DB. The following steps worked fine: createdb -E UTF8 -O user mydb createlang plpgsql mydb I ...
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1answer
97 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 ...
8
votes
2answers
1k views

PostGIS raster value of a lat/lon point

I have a tiff raster in my PostGIS 2.0 database. I want to get the value of the raster at a specified lat/lon point. I have: postgresql-9.1 postgis-2.0-svn with raster support a raster imported ...
6
votes
5answers
5k views

How to load Shapefiles into a remote PostGIS db using command line?

Can we import a Shapefile from a system which doesn't have PostgreSQL installed (client machine) into a system having PostGIS installed? I am getting problem with 'shp2pgsql' and 'psql' since both ...
6
votes
2answers
341 views

Clarification of the “25D” option in ogr2ogr

[EDIT: In my original post, I had received an error that was based on a typo, so I scrapped that part of the question, but left the questions that still apply.] In the ogr2ogr docs it says: -nlt ...
6
votes
1answer
881 views

QGIS WKT Raster Plugin error, what does this mean?

I have been playing with the WKT Raster plugin. I have installed the WKT Raster experimental binaries in PostGIS successfully and followed the instructions in the read me to the letter. When i am in ...
5
votes
2answers
106 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 ...
5
votes
1answer
211 views

How to achieve equivalent to Dissolve from ArcGIS for Desktop using ST_Union?

I am trying to achieve an equivalent to the Dissolve tool from ArcGIS for Desktop using ST_Union from PostGIS but it seems I am not getting expected result. I have one table which has certain ...
5
votes
4answers
2k views

How to convert multipoint layer to point

I have a Spatialite layer which is multipoint (following a QGIS Save As from shapefile). I need it to be PostGIS and POINT. I have tried ogr2ogr -nlt POINT and got 'new row for relation "xxx" violates ...
5
votes
1answer
401 views

How to interpolate polyline or line from points?

We have a lot of points, but with no timestamps to create ways. For now, I've created a sample of the way the points traverse. It's in here, this way can be compared with a Google one. I haven't ...
5
votes
1answer
931 views

Why do TIF loaded into PostGIS lose their colormap?

I have successfully loaded a TIF image (using raster2pgsql) into my PostGIS 2.0.1 database. I can load the raster image into QGIS and it displays in the correct space. However, it has lost all colour ...
5
votes
4answers
1k views

OSM To Postgis & WGS84 problems

I’m trying to import OpenStreetMap (OSM) data into postGIS it doesn’t appear to be working in that features do not appear to be in the correct place.. Using the QGIS OSM add in and a coastal shape ...
5
votes
1answer
352 views

How to filter points based on proximity while inserting into PostGIS?

I have a large amount of locations that need to be inserted to a PostGIS database. However, I'd like to aggregate these points so that if there's already a location, say nearer than a kilometer, then ...
5
votes
1answer
650 views

How to get GeoNetwork to search through PostGIS fields via GeoServer WMS

I can't seem to get GeoNetwork to search through my PostGIS fields via GeoServer WMS. According to the GeoNetwork Documentation: it should loop over datasets served by the service and produce ...
4
votes
3answers
411 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 ...
4
votes
1answer
83 views

Why does only one of the following queries throw an error?

There are 2 SQL queries: SELECT wkb_geometry FROM building_polygon WHERE ST_Contains(wkb_geometry, ST_GeomFromText('POINT (29.4 60.1)')); SELECT wkb_geometry FROM building_polygon WHERE ...
4
votes
2answers
458 views

QGIS saving analysis output as Postgis table

i am using QGIS and Postgis together. I can load data in Postgis and than i import it to QGIS. But i am trying to save an analysis output (example: buffer analysis, voronoi polygon or SEXTANTE ...
4
votes
2answers
353 views

How to find out what features /tags are included in an .osm or .pbf file?

I would like to load osm data into a postgis (postgresql) database. In How to load OSM data into PostGIS preserving all Tags? there has been a solution posted: Download the OSM files (in .osm ...
4
votes
2answers
2k views

How to select segment of linestring using PostGIS?

i have PostgreSQL+PostGIS. I have a linestring: "LINESTRING(60.7014631515719 56.8441322356241,60.7023117507097 56.8445673405349,60.702948200063 56.8447993944193,60.703902874093 ...