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

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PostGIS Raster functions not working

Hopefully I have a simple question that I'm not phrasing correctly in google. I'm trying to learn about storing and producing rasters in PostGIS. There are tons of examples and documentation online ...
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79 views

How to map all 0.001° graticules that contain land?

I'm trying to map all 0.001° graticules (across the planet) that contain land. My first attempt naively tried to brute force this by literally looping over the entire planet in 0.001° increments and ...
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54 views

C# geometry hex decoder

When i am storing in the database things like: Point(90 90). I get back 010100000000000000008056400000000000805640 which is a hex encoding of the geometric type. Does anyone know a library for c# ...
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163 views

PostGIS Column has Z dimension but geometry does not

I am able to create a geomtry column for 3d multiline using this: CREATE TABLE trajectories ( gid serial NOT NULL, vehid character varying(10), state integer, geom ...
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39 views

Postgresql Postgis Query is taking long time

I have a table that included only 472 rows and geometry of table is Multipolygon. I am sending query to databse via PgAdmin III select * from mytable // this query takes 99413 ms this is vey long ...
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46 views

Do large vertex counts in PostGIS cause performance issues in WMS?

I am wondering if large geometry (geometry with large vertex count) in PostGIS might cause performance issues for GeoServer (or other product) in serving the WMS (not WFS)? This question also ask ...
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77 views

Distance Between Two Points vs Length of Linestring

So I have two points that I want to calculate the distance between. If I use: SELECT ST_Distance_Spheroid(point_a, point_b, 'SPHEROID["GRS 1980",6378137,298.257222101]') / 1000 FROM ( ...
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58 views

GeographyFromText and ST_SetSRID+ST_MakePoint different results?

Why am I getting different results? SELECT ST_DISTANCE( ST_GeographyFromText('SRID=4326;POINT(13.401111 52.383343)'), --berlin ST_GeographyFromText('SRID=4326;POINT(9.997559 53.533778)') ...
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1answer
69 views

Error at or near “select” PostGIS

I'm using node.js to connect to a PostGIS database to check if an input feature significantly intersects with an existing feature. The error seems to be with the nested SELECT statement - can anyone ...
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68 views

Binary insert into Postgis geography column results in value being inserted as geometry

When writing WKB as a value (and as a binary parameter) to a geography column, the persisted value is not geography. Example Java is also available here: ...
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48 views

PostGIS Spatial query taking a very long time

I'm trying to return a count of crimes (points) that occur in each police grid (polygons), as well as the geometry data, but the query takes ~22 seconds. This seems oddly high and will be problematic ...
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73 views

Union of several linestring to multilinestring using MS SQL Server

Followed Postgreql query is the existing one used to combine serveral linestring to a single multilinestring. is there any equivalent of this in SQLServer . SELECT ST_AsText(ST_Collect( ARRAY[ ...
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180 views

Hex grid value interpolation in POSTGIS

I have a table of tessellated hexagons that I created as a hex binning grid to cover an area. I've then overlaid a point set to give some of the hexagons a value, see diagram:- The shapes with ...
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55 views

How to export postgis points as blocks in dxf with ogr2ogr

I'm trying to export postgis points as blocks to DXF format. I have a simple table in postgis with columns: CREATE TABLE pod_com_azimuth ( ogc_fid integer, rotation double precision, pointtype ...
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1answer
89 views

How to generate pgrouting source and target with OSM?

Is there anyone here can explain me more details for pgrouting's source and target? I'm wondering how to generate with the given lonlat in OSM PostGIS entities. In pgrouting's website, they are ...
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135 views

How to get the centroid of a set of points in POSTGIS?

I use PostgreSQL with POSTGIS extension. I have a set of points in the_geom column from a table myshema.myobjects I would want create a select statement to get the centroid of this cluster, so from a ...
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123 views

Recommended opensource solution for storing, publishing and querying GIS data

Our company has millions of feature classes currently stored through ArcSDE on SQL Server 2008 R2. We are kind of slowly making our way to opensource software. What we want to achieve is to be able ...
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16 views

How to get pgrouting source and target value using openlayers 2/3?

Is there anyone can teach me how to get the pgrouting's source and target parameters in openlayers 2/3? I plan to get those parameters by click the OSM map layer. Currently, I can only get the lonlat ...
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32 views

Remove inner polygons postgis

I'm trying to remove inner polygons with postgis. I've created a routine, that resumes in: From a polygon table, with a unique id: -Create a linestring table from polygon -Import to postgis -Get the ...
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62 views

How to write a (memory) layer from QGIS to PostGIS?

I am looking for an "elegant" solution to write, from a python script, a layer from qgis and into a new table of a PostGIS database. I thougth that this might be solved by QgsWriteVectorLayer, but I ...
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36 views

Problem in importing .osm file with osm2pgrouting 2.0

i've got two different systems: First system is: Ubuntu linux 64bit Postgres 8.4.8 Postgis 1.5.1 pgrouting 1.05 osm2pgrouting 0.2.0 This the system i've used for an old project that is already ...
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75 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 ...
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1answer
80 views

Pgrouting install debian 7.5 whezy

I need to install pgRouting on a Debian 7.5 64-bit server. I have PostgreSQL 9.1 and PostGIS 1.5 running. But somehow I can not install pgRouting. 1 - To use add-apt-repository ran the command: ...
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85 views

Undefined symbol error when creating postgis extension

When trying to create postgis extension, I'm getting an error, no references in google on it. maptest=# CREATE EXTENSION postgis; ERROR: could not load library "/usr/pgsql-9.3/lib/rtpostgis-2.1.so": ...
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164 views

PostGIS: Insert a Point using Python

What is the right way to insert a Point to a PostGIS database using Python?
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85 views

Extract lat, lon Points from Polygon

I have PostGIS database, and want to extract lat, lon pairs sequence from Polygons (and MultiPolygons). As a very fresh PostGIS user, I'm able to just extract the Polygons: SELECT ...
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57 views

How to add labels parallel to lines, polylines or multilines using Leaflet?

I want to add road name parellel to its line or if the line is curved, then the label should also be curved. How to add these name labels using leaflet? example image
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86 views

Dealing with custom projections (from prj file) in PostGIS (also GeoServer and OpenLayers)

Basically I want to perform spatial queries like distance calculations in PostGIS using data from shapefiles with different projections, some of which have no SRID code that I can find and also which ...
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51 views

PostGIS change column type varchar => geometry

I have a Postgres database with PostGIS extension on it. Also, I have a table with column lat with type (varchar 40). Column values are like this: 52.1432514 52.1431855 52.1431586 I want to convert ...
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485 views

PostGIS non functional on Ubuntu 14.04

I am unable to create the PostGIS extension on new databases in Ubuntu 14.04: $ psql pg_testing -c "create extension postgis" ERROR: could not load library ...
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1answer
59 views

Some items have coordinates switched when loading PostGIS layers in QGIS [closed]

I am having problem with strange coordinates switching when loading PostGIS layers in QGIS. First, I thought, that problem may be cause by the use of GROUP_BY feature in layer query, but later the ...
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58 views

POSTGIS Raster - Merge polygon onto raster

I have two tables, SCHEDULE contains polygon geometries and RASTER contains raster tiles I want to take a polygon from the SCHEDULE table and overlay it on top of a set of RASTER tiles that intersect ...
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38 views

postgis loader osm shapefile

I downloaded the map of my city already in shapefile into postgis http://metro.teczno.com/ to load in order to consult routes using pgRouting. Iss happening the error: http://metro.teczno.com/ ...
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49 views

How to configure osm2po to ignore certain class types?

I'm trying to import data using osm2po but am only interested in driving distances, so I'd like to omit all footway, cycleway, steps, etc. in the imported dataset. How can I configure osm2po to do ...
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1answer
101 views

Counting self intersections of linestring using PostGIS?

Is there a way of using PostgreSQL + PostGIS for finding the number of self intersections in a linestring? I have a linestring that goes forward but in circles, and I need to find the number of times ...
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37 views

Issues ST_MakePoint in PostGIS with Geoserver

I am trying to setup a GIS system to use PostGIS and Geoserver. I have loaded all of the data into a table. The data that is received has long/lat coordinates in Degrees, Minutes, Seconds, Direction, ...
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20 views

Text in POSTGIS Raster

Is it possible to add text/annotation to a raster generated in Postgis raster? Specifically I need to do this within the database if possible and am looking for an option that does not require an ...
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2answers
42 views

How to extract a new linestring vector from a existing multipolygon in QGIS?

What I want to do: create a new line (named linestring in Postgis?) from existing multipolygon layer in Postgis. Purpose: once these lines are created, I'll run some distance calcs from specific ...
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51 views

Calculating driving distance from many nodes (sources) to one target using PgRouting?

I'm using a PostGIS / pgRouting database setup with a road network. And I want to calculate a driving distance and shortest path from many sources to one target. I found that pgr_kDijkstra can ...
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181 views

What is the internal format of PostGIS?

PostGIS stores its geometry entities as long strings: SELECT ST_GeomFromText('POINT(32.0 34.0)',4326); st_geomfromtext ---------------------------------------------------- ...
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52 views

What is best way to reorganize osm into PostGIS database entity?

I'm just wondering how to reorganize the OSM given entity to more flexible and schematic purpose. The OSM gave 4 entities the planet_osm_line, planet_osm_point, planet_osm_polygon and ...
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1answer
25 views

ST_ClosestPoint in 2D but retaining Z value

I have a query in PostGIS where I have a two geometries, a MultiLineStringZ and a Point. I want to find the 3D point on the MultiLineStringZ closest to the Point by it's flat 2D plane distance, so ...
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44 views

pgRouting pgr_tsp() not returning results when used with SQL parameter

I’m trying to solve the travelling salesman problem with locations pulled from a database, e.g.: mydb=# SELECT id::integer, location_lng::float AS x, location_lat::float AS y FROM addresses where ...
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63 views

How to create a vector layer from a GeoAlchemy2 query?

I'm currently developing a QGIS plugin where I mapped a PostGIS database via GeoAlchemy2. I wrote a function that returns results from a GeoAlchemy query but have no idea how to create a vector ...
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169 views

Offline Map Service with Mapnik and Leaflet

I'm relatively new to GIS, so I hope my asking doesn't appear to be ignorant in any way. I currently work on an offline map service solution for usage in areas without internet connection. For that ...
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1answer
213 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 ...
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48 views

How to add a new permanent column that contains result from ST_AREA select queries

I am a total newbie here, I have a bunch of polygons in my cartodb map, and I want to create a new column called "AREA" in the table MY_TABLE that contains values from my area calculation query: ...
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63 views

Keeping up to date with OSM changes in pgRouting

I'm working on a routing application using OSM and pgRouting. I'm only interested in a subset of data, mostly North America (performance was difficult for large amounts of data, so don't want to use ...
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70 views

How to easily remove loose/isolated edges from pgRouting network?

I wondered if there's an easy way to 'clean up' a pgRouting network by removing those edges that do not connect with the global network. Otherwise you risk to end up with cost values of -1, meaning ...
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159 views

Growth of a PostGIS database for Social Media - Move to Cassandra?

I currently have a large and growing database of geo-social media. I'm using Postgres with postgis, and so far it's been quite good. My use case thus far has been to query the database for all posts ...