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

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Planet_osm_point versus Planet_osm_nodes for querying places

Hello I am using a PostGis Database with OSM Data. After importing the data with osm2pgsql in slim mode I found a table named Planet_osm_nodes that has places also. It seems really compressed and has ...
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1answer
60 views

How to detect gaps in a MultiPolygon table with Postgis?

I have mapping of land use. In it, I need running topology to detect gaps between polygons. Is there postgis's function to do this? Thanks
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64 views

pgr_drivingdistance wrapper

Pgr_drivingdistance function works as : SELECT seq, id1 AS node, cost FROM pgr_drivingDistance( 'SELECT id, source, target, cost FROM edge_table', id, distance, false, ...
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26 views

QGIS opening file - Very slow on POSTGIS databse with many layers

When opening a qgis file with many layers (20 or so) it takes +5 minutes to load. All the layers come from a single PostGis database. When looking into the server logs, i see that there are many ...
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41 views

How to work with SRID using PostGIS [duplicate]

I am using PostGIS with OSM Data from Geofabrik that covers the complete area of Austria. I am used to work with calissical longitude and latitude. If you enter Vienna, Austria in ...
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63 views

How to implement a radius search using PostGIS

I am very new to this topic and after a long time of research I didn't find a solution. I want a query that I can use on my PostGIS database performing a radiussearch.. I inserted the Open Street Map ...
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47 views

Connection to Shapefiles and PostGIS

I have this HTML (see below) code, I want to connect to PostGIS to the Shapefiles I have loaded, but I can't find where and how to accomplish that. I want my map to display this Shapefiles when the ...
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37 views

Is there any VRP solver in Pgrouting 2.0?

after looking at older posts and googling for a while i guess there is not vrp solver (multiple trucks). there was DARP in pgr1.x but i can't see it in 2.x. i found a lot of information on ...
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34 views

How to Make WMS (ArcGIS Server) automatic query top raster from PostGIS Database

I've a question about using ArcGIS Server in this scenario: PostGIS table with fields (ID, time, ras:raster, linkpath to file .tif in folder:char) eachday, we put some images in this table ...
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3answers
55 views

Calculate Color of Object So No Adjacent Objects Repeat

I am attempting to assign one of 16 colors to map objects (e.g. counties, states, ZIP Codes, etc.) so that no two adjacent objects share the same color. I'm seeing tons of articles online about ...
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32 views

line features show up as polygons in GeoServer

the layers are located in a postgreSQL Enterprise Geodatabase. I created a new line feature class and added it to the database and then added it to geoserver. But in geoserver it comes in as a polygon ...
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30 views

Syntax error drivingdistance

I am new in sql and i am trying to get that works a subquery with pgr_drivingdistance and pgr_pointsaspolygon but i get the next error: subqueries in FROM must to have an alias,for example, FROM ...
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1answer
62 views

Load PostGIS or Oracle Spatial Raster Layer using PyQGIS

How do we load Rasters stored in PostgreSQL-PostGIS or Oracle Spatial 11g into QGIS using PyQGIS? I am able to load vector layers from Oracle 11g with below code. What changes are necessary to add ...
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1answer
87 views

question about Pgrouting dijkstra algorithm

I own two tables one with streets and one points, i use the table with the roads to calculate routes with dijkstra algorithm. But I want when someone add one point in the table Point and this point is ...
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1answer
27 views

How to find out postgis.backend?

How can I find out which postgis.backend (geos or sfcgal) I have?
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1answer
78 views

Adding Nodes to Linestrings at Overlapping Points with Polygon Layer in Spatialite

I have two Spatialite tables. A table called 'lines' which contains a PK column called OGC_FID and a LINESTRING column called GEOM. A table called polys which contains a PK column called OGC_FID and ...
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55 views

How to get Geography data to GeoJSON in PostgreSQL?

I am using PostgreSQL database and there is a field in a table(area), i.e., public.geography(Points,4326). It contains below type of records "0101000020E6100000BA83D89942334540780B24287ED051C0" I ...
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1answer
36 views

ERROR: attempt to redefine parameter “postgis.backend”

I just install "SFCGAL". When I use "ST_3DIntersection", It get below error: ERROR: attempt to redefine parameter "postgis.backend" SQL state: XX000 How can I fix? I already saw ...
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1answer
30 views

Can I make tiles of a raster in postgis?

I am doing some work on dtms in postgis. To import the dtm, I snipped it into tiles and the work directly on the dtm works fine. Then I calculated aspect and slope of the dtm and got some bad ...
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2answers
101 views

Finding all ways that are partly within a bounding box

I'm trying to write a query that will return all OSM ways which are contained within a bounding box of min/max gps coordinates. I get these cooridinates from the greater london bounding box on ...
2
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1answer
26 views

Coloring multilinestringzm M values in QGIS

I have output from a geophysical technique that produces X,Y,Z and scalar value for millions of points, which have been stitched together appropriately (by networkx if it matters) into ...
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1answer
59 views

Does ST_Intersection work in 3D?

I am using "ST_Intersection" between two 3D lines which I believe do not intersect, but the result gives me their intersection. SELECT ST_ASText(ST_Intersection( ST_GeomFromText('LINESTRING( ...
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2answers
33 views

Can GeoServer Mosaic extension footprints be something other than a shapefile?

According to the GeoServer documentation for the Image Mosaic extension... http://docs.geoserver.org/2.4.x/en/user/tutorials/imagemosaic_footprint/imagemosaic_footprint.html It asks for a shapefile ...
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3answers
147 views

Postgis installation

I am installing Postgis on my Debian server, following these instructions: http://postgis.net/install/ (Ubuntu / Debian) https://wiki.postgresql.org/wiki/Apt However, after following the ...
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1answer
76 views

PgRouting function wrapper

I'm trying to adapt the pgr_fromAtoB function to pgr_fromAtoMult replacing pgr_dijkstra function to pgr_drivingdistance.Here is the code: CREATE OR REPLACE FUNCTION pgr_fromAtoMult(IN tbl character ...
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POSTGIS get the max length of the polygon and the average width

I have in postgis a polygon type table. I need to calculate automatically the maximum length of the polygon: And the second one is the average width: I am doubting rigth now if this is possible ...
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58 views

QGIS Plugin for PostGIS versioning

Does anyone of you know a QGIS-Plugin for Versioning PostGIS-Data? I know there was pgVersion of Horst Düster but as far as I know this was not updated for QGIS 2.x (at least not for the "normal" QGIS ...
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2answers
255 views

Find headwater polygons

This is a follow up question to this question. I have a river network (multiline) and some drainage polygons (see picture below). My goal is to select only the headwater polygons (green). With ...
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1answer
24 views

Postgis: Conflation of two vector layers into a single layer

If I have table A that I consider to be definitive and table B that may have some elements missing from table B but also has geometries that are "close" to those in A that I want to ignore. How could ...
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1answer
13 views

ST_AsLatLonText () rounded

I know this is a POSTGIS question… I set a field with UPDATE members SET latlong_degree = ST_AsLatLonText (the_geom) But the result is (for example) 48°37’41.742”N 9°17’55.716”E The seconds part ...
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33 views

How to get changeset tag from .osm file into PostGIS enabled Postgres db

End goal: visualize geographic data from .osm file with QGIS by adding PostGIS layers which include changeset information. I have used osm2pgsql successfully to populate PostGIS and visualize the ...
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1answer
111 views

PostGIS ST within does not exist

I'm quite new to postgresql and postgis so this error will probably due to some rookie mistake. I want to run the spatial query ST_within. When I describe the query like this SELECT nw.entity_id AS ...
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28 views

How to create unique plane with PostGIS?

How to create a unique plane, with (x , y ,z) as center and a vector as normal, in PostGIS? I already saw "Make3DBox" function, but it does not make a unique one.
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41 views

Can you do aggregate functions among nearby geometry in PostGIS?

I want to do aggregation based not on group but on geometry, is that possible in PostGIS? For example to calculate max, min, average price for all listings that's nearby a geometry point, how can I ...
3
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1answer
66 views

Visualising a raster PostgreSQL table in QGIS

I have imported a raster tif image into PostgreSQL with this command: raster2pgsql -s 32643 -I -M filepath.tif -F -t 100x100 public.databassename > filepath.sql And imported the output SQL file ...
3
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1answer
87 views

PostGIS multiple conditional statement on spatial join

I want to make a multiple conditioned spatial query in PostGIS 2.0/PostgreSQL 9.3., OS Windows 7. There are 2 tables, cadastre (Polygon) and roads (Linestring). Query: Select the sum (one number) of ...
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2answers
53 views

Y-coordinates offset in Tilemill

I own a project created with TileMill in SRS 900913. The data source is a Postgis database with the same SRS. When I'm loading the file generated with TileMill (mbtiles) in QGIS and I'm putting under ...
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3answers
101 views

Spacing a set of points

I have a shapefile of a set of points that I want to space out. I DO NOT want to do this using line interpolation as I run the risk of placing a point where there wasn't one before. I can load this ...
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2answers
399 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. ...
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31 views

Convert Postgis tables to DWG

Is there a simple way of converting a postgis table to DWG for a given table name? Regards,
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2answers
61 views

Problem in importing shapefile to Postgis with postgis Shapefile manager

i have a problem with importing my shapefile to postgreSQL, it's a poroblem with the encoding, here's the screenshot: i tried to change encodingin "options" buti get this message: "Failed in ...
3
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1answer
69 views

How to display OSM relations (in QGIS) from osm2pgsql populated PostGIS DB

I have a PostGIS DB populated with OSM data (osm2pgsql, standart.style). Now I would like to display a hiking trail (http://www.openstreetmap.org/relation/51855). It would also be fine, if I just ...
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1answer
60 views

PostGis - BBox -vs- ST_intersects Queries

CartoDb Recommend here that the following query is faster than an St_intersects Query SELECT * FROM {table_name} WHERE the_geom && ST_SetSRID(ST_MakeBox2D(ST_Point(-73.9980, 40.726), ...
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1answer
14 views

Raster2pgsql overview method

What is the method used by Raster2pgsql to create overview? I couldn't find details in the docs. Nearest neighbor isn't a very good choice for the dataset I'm working on, but that seem to be the one ...
4
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2answers
192 views

PostGIS ST_Union Performance

I'm trying to execute a 'dissolve' operation in PostGIS using the ST_Union command. The input layer is admittedly quite large and complex. By 'large' I mean 57,771 features, with number of vertices ...
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1answer
76 views

Querying Postgis data in R using dplyr package

Does anyone have a workflow for querying postgis data in R using the dplyr package? R doesn't like the spatial columns in postgis data so can't read them in like a postgres table. I get the error ...
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1answer
49 views

How to choose a SRID and what is its meaning? [duplicate]

I'm new to GIS, in PostGIS, and I'm struggling with the SRID concept. How do you choose a SRID for a database column? This is making me crazy. Why do I need to choose a SRID? What's its meaning? ...
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1answer
26 views

Walking-Driving area with Leaflet,OpenLayers

Could be possible to get a walking or driving distance area using pgr_drivindistance,pgr_alphashape and/or pgr_pointsaspolygon when an user click any location on map with Leaflet or OpenLayers?. I ...
3
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0answers
88 views

Spatial query too slow to handle bigger OSM extracts

I'm trying to compute some statistics for OSM data using PostgreSQL 9.3.5 and PostGIS 2.1.4. I started with a small bavaria extract which I downloaded from Geofabrik. The db schema is the normal API ...
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52 views

How to choose data type and SRID, for coordinates from different sources, in a medium size zone

I'm developing an application. In the database I need to store coordinates for many places, in the north-east of Italy, but the area could expand in the future. This coordinates will come from some ...