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

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2
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1answer
823 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
559 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
450 views

PostGIS: ST_Transform function conversion problem

I'm inserting map data from a GML file with srid EPSG:27700 into a PostGIS database table with srid EPSG:4326. I'm using the ST_Transform function as in this snippet: ...
2
votes
1answer
907 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
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1answer
640 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 ...
1
vote
1answer
185 views

Configuring SFCGAL to PostGIS Db

I was using PostgreSQL with PostGIS and Pgrouting. Recently I needed to install SFCGAL for some extra functions for my PostGIS db. After installing SFCGAL, now I don't know how to update my PostGIS db ...
1
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1answer
88 views

How to compute a line intersection point in a street layer in postgis 1.4?

I have a street layer downloaded from osm. I need to calculated intersection point as we do in qgis from vector menu -> Analysis tool -> Line intersections. I am new to postgis/postgres. any how i ...
1
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1answer
190 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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0answers
191 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 ...
1
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1answer
143 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 ...
1
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2answers
1k 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 ...
1
vote
1answer
755 views

How to improve poor performance times for PostGIS 2.1 Tiger Geocoder?

I've recently upgraded my PostGIS DB from 2.0 to 2.1. I initially followed the instructions from Waiting for PostGIS 2.1 - Install PostGIS Tiger Geocoder as an Extension and 2.7. Installing, ...
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3answers
137 views

Query to find the Intersection coordinates of multiple Polyon

I am using the below Query to find out the intersection coordinates of 2 Polygon and its working fine,but how to use or modify the query to find the intersection area coordinates for multiple(or N ...
1
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 ...
1
vote
1answer
602 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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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 ...
1
vote
1answer
266 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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2answers
2k views

How to offset point perpendicular to line direction in PostGIS

I have a postgis table of points, that are sitting on road centerlines (I've linear referenced them). And the second table with road centerlines themselves. The point table also has a field roadid and ...
1
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0answers
558 views

How to add ECW support to GDAL bundled with PostGIS Windows

I'm currently trying the new raster functionalities of PostGIS 2.0 and I successfully imported some GeoTIFF file into PostGIS (although it only find one band so it's all black and white for some ...
0
votes
1answer
44 views

Find nearest node function

I am trying to get work the next function but i don't know if it is incomplete because the query SELECT * FROM pgr_nearest_node1('jaen',-3.75,37.779); does not provide any results. Here is the ...
0
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1answer
136 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 ...
9
votes
2answers
2k 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
2answers
397 views

Find start of river

Edit: Follow-up question here (= Find headwater polygons). How can I determine the start of a river in PostGIS? I have a river network (Multiline) and want to find the startpoints of the rivers. ...
6
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2answers
1k views

GeoServer: Shapefile or PostGIS?

I'm going to build a web application, which will render around ten maps using GeoServer. I will be also changing the attribute data in the application for some layers. So, what is the recommended ...
6
votes
2answers
365 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
925 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
1answer
275 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
3k 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
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1answer
456 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
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1answer
1k 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
1answer
963 views

Raster data on PostGIS

I need to publish raster and vector data through GeoServer WMS service and I have already chosen PostGIS as datasource to keep vector data. Now I would like to know what is the best practice to work ...
5
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4answers
2k 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
366 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
684 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
670 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
2answers
3k views

What is the unit used in ST_Distance()?

I wonder what the unit is of the float being returned from ST_Distance. In the documentation it says: ...cartesian minimum distance (based on spatial ref) between two geometries in projected ...
4
votes
1answer
92 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
496 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
3answers
492 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 ...
4
votes
2answers
2k views

How can I get the geometry length in meters?

The ST_length() function returns the length of a linestring but not in meters. Is there a function like ST_Length() but in meters?. Thanks!
4
votes
1answer
225 views

Update PostGIS after updating GDAL?

I am using PostGIS 2.0 and I want to use the raster functionality through mapserver. It seems as if the latest official GDAL release 1.9.1 has an unstable PostGIS raster driver, as pointed out in a ...
4
votes
1answer
905 views

How to save a newly created shapefile in PostGIS?

I am creating shapefile using shapefile.py and my database has records more that 65k which is the limit of the shapefile. How can I create shapefiles then? Is it possible that somehow I am able to ...
4
votes
1answer
349 views

Self-intersecting polygon using extreme values

I have this polygon POLYGON((1.2E-15 1.1E-15,1.31E-15 1.21E-15,-180 -90,180 90,1.2E-15 1.1E-15)) It uses an extreme coordinates like (1.2E-15 1.1E-15) and (180 90) When I call ST_isValidReason, ...
4
votes
1answer
2k views

Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database

This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc. I have tried the ...
4
votes
2answers
709 views

Indian Latitude Longitude values

I am in need of around 10000 and odd Indian latitude and longitude values for my openlayers project. I have to load them in a postgis db. so a sql file or atleast text file would be better than a ...
3
votes
2answers
293 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 ...
3
votes
2answers
378 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 ...
3
votes
1answer
608 views

Importing grib, grib2, netcdf to PostGIS

According to grib2 to raster? (grib2 -> raster2pgsql -> PostGIS 2.0 -> GeoServer), it seems like that grib2 can be treated as raster directly. Is it the so called "standard" way? How about ...
3
votes
3answers
643 views

Create a point x meters from origin using st_translate in postgis

How do I create a point 1000 meters away from a reference point? The ST_Translate only supports geometry type. I also tried using ST_GeomFromText but that returns a unit and not in meters. Here is ...