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

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Complexity of A-star algorithm using pgRouting in a graph

I'm using the A-star algorithm in pgRouting. It uses the Manhattan distance as a heuristics ((|dx|+|dy|)/2). What would be the time complexity in a standard route network? Based on Why is the ...
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168 views

Write Nominatim-like geocode query using only PostGIS functions?

I'm new to PostGIS and was anticipating being able to write geocode queries using only the functions provided by PostGIS. However, once I loaded my database using osm2pgsql and discovered tables like ...
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136 views

identify subgraphs within planet_osm_line table

I want to identify subgraphs within the planet_osm_line table of the osm2pgsql-schema. those subgraphs are classified by certain tags i want to check. My first attempt was to do this recursively with ...
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154 views

pgRouting results to LINESTRING geometry type

I am doing some routing queries, using pgRouting's second version of pgr_trsp function. What I can't do effectively yet is storing the results. That is, I want to able to store in a table: either ...
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128 views

Merging contour lines along tile boundaries

I am working with the CANVEC data set. The data in canvec is broken up in to mapsheets. eg. 116B04. I have data covering the entire province of the Yukon. I have merged all the data in to one ...
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100 views

Upgrading Postgres database to Postgis 2.1.1

I executed the postgres 9.1.6 with Postgis 1.5.8 dump from a remote server on Linux pg_dump -h localhost -p 5432 -U postgres -Fc -b -v -f "/somepath/tumidb9.1geom1.5.8.backup" tumidb9 So I have a ...
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60 views

Problems with versioning

I have 5 PostgreSQL_PostGIS database in my company and i conneting on them through ArcSDE. Four of database work correctly, only with one i have i realy big problem. When i make two versions of ...
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75 views

How to get from GeoServer a KML of the external boundary of several areas

I have a GeoServer with PostGis database. PostGis database has a table with small geographic areas (English LSOAs and output areas, to be precise), with codes and shapes. I want to submit to ...
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51 views

Selecting a rectangle box from a raster tiled table in PostGis 2.1

I am new to PostGIS as well as SQL queries for rasters. I have imported a raster .tif file into PostGIS with tiles. I would need to select a bounded rectangle from within this raster using SQL ...
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115 views

SQL procedure(s) to convert GPS traces to an ordered set of junctions in a network

I have three datasets that I have loaded into a geodatabase (spatialite or PostGIS): A set of GPS points collected from individual trips through urban areas. Points have a unique point id, a group ...
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45 views

Upgrade Postgres/Postgis

I have Postgres 8.4 and postgis 1.5.3 installed on centos6. Now I need to upgrade both to postgres 9.x and postgis 2.x. Is there somewhere a good tutorial how to upgrade without removing the old ...
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369 views

Using PostGIS with Postgres.app (9.3)

I'm trying to run CREATE EXTENSION postgis; on a fresh 9.3 Postgres.app install. I get this as a return: ERROR: cannot change return type of existing function HINT: Use DROP FUNCTION ...
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103 views

Use bbox in geoserver sql view

I'm doing this sql query using geoservers sql views: SELECT kmeans, count(*), ST_BUFFER(ST_CENTROID(ST_Collect(geom)), qrt(count(*))*1000 ) AS geom FROM ( SELECT ...
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23 views

Overview effect on postgis polygon table

Is There a Way, with postgis and qgis, to reproduce the overview effect of tiff Raster on a polygon table in order to increase speed? What if we could create simplified versions of this table,gathered ...
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196 views

GeoTools example for Shapefile export to already existing PostGIS table

I'm a newbie to GeoTool API, and I'm looking for a way to export the specific shapefile to the specific already existing PostGIS table with GeoTools (the underlying problem I face is that PostGIS ...
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30 views

PostGIS. Obtain the rotation between two equal Geometries

I've got two features with the same drawing (poliline) but one is rotated relative to the other. I would like no know in PostGIS the rotation between the two geometries to apply this rotation to a ...
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73 views

Is there tutorial available for PostGIS setup in ArcSDE 10.1 geodatabase on Linux?

Is there any tutorial for Set up PostGIS in an ArcSDE 10.1 geodatabase on Linux? There is one in tutorial arcgis 9 for ArcGIS version 9, but I couldn't find any for ArcGIS 10.1.
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101 views

PostGis search query on hstore tags

I am writing a search client, to query postgis db. The search query will be, SELECT tags->'name' AS name,ST_Transform(way,4326) AS pt_lonlattext FROM planet_osm_point WHERE lower(tags->'name') ...
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144 views

Problem import shapefile in PostGIS database

I am having a Polygon shape-file. When I try to import this shape-file in PostGIS some of the attributes in Geom Field is found empty. But in attribute table when I select that polygon It is visible ...
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53 views

How do I make vectorlayer with sql on PostGis via python code

I need to make a vectorLayer and fill with the SQL's results on PostGIS via python code. I'm working with python 2.7, QGIS 1.8 and PyQt 4.5 How do I it ? thanks
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287 views

Loop though records in PostGIS (using PL/PYTHON or PGSQL)

I've seen many example of loops, but I can't get that one to work. I work for a regional transit agency and each year, we conduct several surveys. I geocode everything to the house level for internal ...
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361 views

save features from openlayers to postgis via nodejs and websockets

I try to save features created on a vector layer (openlayers) to postgreSQL 9.1/postGIS 2.0 via websockets. As server I use nodejs 0.10.12 along with the pg module I cannot fix it. Its getting so ...
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234 views

MapServer Clustering GetFeatureInfo

I'm having a bit of a problem with clustering in map server the clustering itself works fine and the GetFeatureInfo works fine most of the time. However some times when I click on a cluster point it ...
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134 views

can Geocat Bridge enable me to connect to existing PostGIS database and make edits through ArcGIS?

We are planning to set up a Webgis to share our GIS data on the web. Currently, we are on a desktop GIS and using ESRI's File geodatabase format. We are considering ArcGIS Server or using Opengeo ...
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Can I speed up very long connection times to a PostGIS DB caused by complex views?

When connecting to a PostGIS database to add a postgis layer, all table and views are scanned by Qgis in order to define the geometry type (if I understand well the query performed). My problem is ...
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60 views

Can't edit osm_roads in udig

There is a PostGIS database that has a road network imported from Open Street Map, stored in osm_roads table. For the testing purposes I need to change some road geometry there. I tried to edit it ...
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73 views

database-backed WMS service runs as transaction

I'm trying to tame a geoserver 2.3.2 installation (backed by Postgres 9.1 and Postgis 1.5) by determining which of the many, many layers are actually being used. To this end, I've set up an audit ...
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57 views

Query OSM ids by name in PostGIS

I installed PostGIS on a server and now I want to query the OSM ids referring to a name, in order to get a list of all geometries according to this name. Is there an efficient way to query this ids ...
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53 views

windows function with points in a mixed (multipoint/point) table

I have a table comprising multipoints (tracks) and points (stops between tracks). there can be several consecutive multipoints. now, i want to merge any points lying very closely to each other ...
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142 views

How can I combine these two commands? (Get a clipped raster ASC-II file from PostGIS)?

My objective is to clip a polygon from PostGIS raster table, and then save this raster (draw polygon shape) as an ASC-II in a folder. What I did now are 2 steps. 1st Step: Insert the clipped raster ...
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98 views

An algorithm for locating candidate labelling boxes within a polygon

Has anyone implemented this algorithm In PostGIS? Quoting from the paper: Vector-based geographic information systems usually require annotation, such as a polygon number or attribute data, in a ...
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492 views

How to add legend in WFS openlayers

How can I publish WFS openlayer with legend, have tried different examples such as http://api.geoext.org/1.0/examples/vector-legend.js. But when I tried using this firebug shows an error=> ...
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92 views

Identifying Intersections of Geology using PostGIS

I'm having problems identifying intersections on a layer of linework, the lines are representative of contacts and faults (geological rock formations). I am trying to select where there are connected ...
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133 views

Creating polygons for a choropleth map using PostGIS

I have a grid of points, each with a value to it as shown in the image below. The data was retrieved from PostGIS and rendered in Quantum GIS. The final result should be a polygons of a choropleth map ...
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695 views

PostGIS Better ST_Intersects Query

I am currently using the following queries to return all features that intersect a large and complex polygon. I initially tried to use a single ST_Intersect query but because the number of features it ...
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306 views

Can I use RGeo::Point data in PostGIS queries without multiple conversion?

How can I represent RGeo::Point ( CAPI implementation ) in some way where I don't have to convert it once more in Sql? Now I have something like this: class Poly scope :enclosing ->(geom) do ...
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62 views

New geographical point won't show on map

I did recently ask a question about how to add a new point to a PostGIS table. Now when I've got the new point in the table it should be visible on my map, but it isn't. I'm using Mapnik together ...
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111 views

calculating st_simplify tolerance for openlayers

I want to display a vector layer in openlayers. Users can scale the map before they load the vector layer and I'd like to simplify the geometry with st_simplify before sending it to the client. Does ...
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287 views

View PostGIS geometry in QGIS

I am a newbie to GIS systems so please be patient. I have a PostGIS database set up with a spatial data table. One of the columns is of Geometry type and contains Points with SRID 4326. I want to ...
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85 views

How to import multiple shapefiles each with different source projections to postgis

I have a couple thousand .zip files each with a .shp, .dbf, .shx, and .prj inside them that I want to load into postgis. The problem is, they have many different source projections (each defined in ...
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145 views

Problems combining (union) Multipolygons in geodjango

I'm using geodjango and postgis (1.x), What is the best way to combine (union) a list of multipolygons. in what i assume is rather inefficient i'm looping trough like this combined = multipolygon ...
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87 views

postgis union geometries in consecutive order

Database is postgres 9.2, POSTGIS="2.0.2 r10789" GEOS="3.3.6-CAPI-1.7.6" PROJ="Rel. 4.7.1, 23 September 2009" LIBXML="2.7.8" i have geometries in consecutive order. Here is query: SELECT ...
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96 views

Postgis walk through multilinestring

Maybe question title not correct, i have no idea how to formulate my question. Database is postgres 9.2, POSTGIS="2.0.2 r10789" GEOS="3.3.6-CAPI-1.7.6" PROJ="Rel. 4.7.1, 23 September 2009" ...
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125 views

Are there limitations with gdal virtual raster option?

I am new at Postgis and I'm groping... I pretend to rasterize some weighty vector layers in Postgis, do some map algebra and reclassification with them and visualize intermediate as well as final ...
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451 views

How to merge linestrings which are connected with each other?

I would like to join linestrings which are connected to each other. The preferred output is a longer linestring based on all joined single linestings! The table that holds my single linestrings is ...
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191 views

Break LINESTRING values in postgis into mutiple LINESTRINGs

Figure A below is the visual representation of what i have in my road data set. Line 1, Line 2, Line 3 in illustration are each represented as 1 row postgis DB inside a geometry column, some of these ...
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91 views

How can I snap 2 lines in QGIS so the st_distance between them is 0?

Sometimes when I snap the ends of 2 LineStrings together and I check the st_distance between those endpoints I get a value in the order of 1.1E-10 while at the same time when I check for equality of ...
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206 views

Renaming Columns in Geotools FeatureType

I am attempting to build a simple java program that loads shapefiles into a Postgis 2.0 database. Everything is working out great except that I would like to be able to modify the FeatureType in the ...
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130 views

django + apache mod_tile

I'm not sure if I'm doing this right and I need your opinion on this current situation. I'm creating a Web Interface using django and postgres as the database. With regards to the slippy map, I went ...
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189 views

Why is not ST_GeomFromEWKB() working?

The following SQL is working fine from the terminal: SELECT MIN(ST_Distance( ST_Transform(ST_GeomFromText('POINT(-3.163916 55.926528)',4326),32630), ...