Tagged Questions

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

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6 views

Index to speed up ST_HausdorffDistance?

When comparing similarity of linestrings with ST_HausdorffDistance (or another type of similarity function), is there a way to use an index to speed up the search for similar linestrings?
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1answer
40 views

How to import multiple shapefiles without any dbf to a postgis database?

I have a polyline shapefile (.shp and .shx) without .dbf. I would like to import the shp into Postgis. In order to do that, I created the corresponding .dbf using the r code provided by mdsumner in ...
2
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1answer
40 views

PostGIS Nearest Neighbour outside buffer

I am trying to find the 6 nearest neighbours to a point which are outside a defined buffer. Basically I am comparing points of the same table and working with Mike Gleason's examples. WITH subq AS ...
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0answers
21 views

Create a “wide” table recording all overlaps between polygons in PostGIS

I have a set of overlapping polygons and would like to record which polygons are overlapping at each intersection. I have followed the instructions at: ...
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0answers
10 views

postgis & mapnik “column ”CLASS“ does not exist”

I've piped an osm map of greece into postgis with osm2pgsql and was playing around with C++ mapnik sample code giving "planet_osm_polygon" as the source table: parameters p0; p0["type"] = ...
3
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1answer
53 views

SQL “Case” statement when count(*) is 0

I am trying to write the following SQL command using case clause. with x as (select the_geom as geom from table1 where st_dwithin(the_geom, st_setsrid(st_makepoint(28.959495,41.019913), 4326), ...
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2answers
22 views

Insert values in Postgresql in Java

Hello i try to insert same values in my table but i write this code String sql = "INSERT INTO points (gid, osm_id, name, type, geom)VALUES (?, ?, ?, ?,ST_GeomFromText('POINT(?, ?)', 2100));"; ...
1
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1answer
31 views

Modifying “pg_hba.conf” file to listen local TCP/IP conection

I am starting with PostGIS and there is an error when trying to connect through a TCP/IP connection. What I have done is: installed PostGre 9.3 in my PC, then installed PostGIS 2.3 for postGre 9.3, ...
3
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0answers
21 views

Prevent PostGIS Topology from splitting edges on line insert

I'm dealing with a large amount of road data represented with PostGIS Topology types. Anytime I add an edge over another edge, the edge is automatically split and a new node is created at the ...
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0answers
13 views

postgis st_makeline, points with rounded time

I have seen a number of example SQL statements that take gps points, order them by time, them use ST_MakeLine to make a Linestring. I think my trouble comes from that fact that my times are rounded to ...
0
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0answers
15 views

cartodb/postgis : how to display a polygon with longitude outside the -180;180 range

I am trying to display the following geojson polygon: { "type": "FeatureCollection", "features": [ { "type": "Feature", "properties": {}, "geometry": { "type": ...
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1answer
22 views

How to modify imposm data mapping in order to include the user name?

I want to import OSM data into postgresql with imposm. How do I have to modify the import process in order to have the user name as an attribute in my tables? Do I have to change that in the data ...
1
vote
1answer
15 views

Does mixing geometries of different granularity affect POSTGIS index efficiency?

My POSTGIS table contains a lot of small non-overlapping geometries and I do mostly bbox queries. I would like to add larger / coarser grained geometries to the database (counties, provinces, country) ...
1
vote
1answer
44 views

Computing intersections for each geometry in a table

I have a table with many Linestrings and for each of these Linestrings I need to figure out which other Linestrings, from the same table, intersect with it. If I recall correctly this gives me a ...
0
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2answers
16 views

Create a point on a line after a specific distance from startpoint

I'm trying to create a point on a line after 10 meters from the beginning of the line. In postgis it is possible to create a point on a certain fraction of total length of linestring ...
0
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1answer
49 views

How to create a Network Topology in a shapefile that contains only nodes(geometry points)?

I want to use pgrouting with the shapefile but when I use : alter table network.publictransport add column source integer; alter table network.publictransport add column target integer; select ...
1
vote
1answer
27 views

Hardware requirements for one instance Geoserver/PostGIS

What hardware minimun requirements do you recomend for one instance of geoserver and postgis and 20 concurrent users? Vectorial data stored in PostGIS is around 20 MB only. I need the ammount of RAM, ...
0
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1answer
28 views

Export shapefile From PostGIS

I've a website where I'm giving the functionality of creating and editing line features. I'm using Leaflet-Draw plugin for drawing, PostGIS for storing the data and GeoJSON to display it on map. My ...
2
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3answers
45 views

ST_MakePoint or ST_PointFromText to generate points

I'm new to postGIS and am having trouble finding an answer to this question. I have loaded UK postcode data (OSGB36, SRID 27700 with eastings and northings fields) into a postGIS database. I now want ...
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vote
1answer
24 views

Why does my query not run since SRID are the same?

I am running this query: SELECT source,ST_AsText(ST_ClosestPoint(roads.geom,ST_GeomFromText('POINT(22.256 39.569)'))) FROM roads ORDER BY ST_Distance(roads.geom,ST_GeomFromText('POINT(22.256 ...
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0answers
21 views

How to use pgRouting in my case?

Suppose I have 6 bus route and a road network. After a user determines to me the starting point and the place he wants to go, I want to determine which of the bus routes is the best. How to use ...
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2answers
54 views

How to visualize pgrouting result?

So I use this query SELECT seq, id1 AS node, id2 AS edge, cost FROM pgr_dijkstra(' SELECT gid AS id, source::integer, ...
1
vote
1answer
32 views

QGIS WFS-T not updating data

I have asked for help on this topic a few times, but i'll go one more time; with a bit more info. I am trying to edit a WFS from geoserver (using PostGIS data) within QGIS. This is the request as ...
1
vote
1answer
30 views

What does st_hausdorffdistance Actually Compare

Does st_hausdorffdistance just look at discreet points used to construct a line segment or does it compare two line segments as a continuous set of points? Also, the points used to construct my line ...
0
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0answers
50 views

Converting GPS coordinates points to polylines

I happen to have some GPS coordinates points based on timestamp in a table. My table consists of and id , time_stamp and GPS points as the geometrical data. I want to create a line by joining all ...
2
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0answers
17 views

postgres repojection: best practice

I have a postgres/postgis database. I would like to reproject those data coming to me in 4326 to 32736. For those tables with lat long info in wgs84 (4326) I have set the geom to 4326. Then I have ...
0
votes
1answer
12 views

Error while make Build osm2pgrouting on openSUSE 13.2

i am getting the error while make /usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/bin/ld: cannot find -lpq collect2: error: ld returned 1 exit status make[2]: *** [osm2pgrouting] ...
1
vote
1answer
13 views

How to join LINESTRINGS in a specific order in PostGIS?

I have a path from point A to point B, which I want to double back on itself to create a path from A to B back to A. It seemed like using ST_LineMerge on the MULTILINESTRING created by ST_Collect ...
1
vote
1answer
26 views

Import KML to PostGIS

I am looking for a way to import my data from KML (example below) to PostGIS database. <?xml version="1.0" encoding="UTF-8"?> <kml xmlns="http://www.opengis.net/kml/2.2" ...
-3
votes
1answer
40 views

How to use st_touches to get all nearby states

I have a table with all US states geometrical data: USstate ------- state | The_geom (here filling in random value) AL | 00012312 NM | 000234234 NJ | 0000234534 NY | 00005465 ...
-3
votes
1answer
44 views

How do you combine multiple spatial functions in one query?

I want to find out the intersection and difference in the same query using postgresql. How can I combine both st_intersect and st_Difference in same query and return the result.I want to compute the ...
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0answers
12 views

TileStache some vector tiles failing / postgis connection error

I have TileStache running fine with NGINX/uWSGI on my server. Problems start when I try to render data as vector tiles from a postgis datasource. A few tiles will normally work fine, but at some ...
0
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0answers
25 views

Capturing points slightly out at sea

I have two tables one containing points (points) and the other polygons (polygons). I want to generate a two-columns table identifying for each point of the first table the polygon containing it. So ...
1
vote
1answer
35 views

Conversion of EPSG:3857 coordinate to UTM

I'm trying to convert coordinates from Google Maps using the PostGIS. I'm using this query: SELECT ST_AsText(ST_Transform(ST_GeomFromText('POINT(-29.16297 -51.1795034)', 900913), 29182)); The ...
0
votes
1answer
19 views

Merge Point Data and Raster using ST_SetValues in PostGIS

I'm trying to merge a point dataset with a raster dataset using Column X / Row Y. I have written a tool which generates a raster and, from that raster, I have created grid points with ...
0
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0answers
26 views

Geohash36 for PostGIS

i was wondering if anyone created a ST_GeoHash36 function inside postGIS, i know the ST_GeoHash + ST_GeomFromGeoHash functions exists, But i need the geohash36 function inside postGIS, i need a ...
0
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0answers
20 views

OpenGeo Suite and External Gui [closed]

I am creating an application using Open-Geo Suite. I have already created a war file from ol3edit template and it worked just fine. Now If I was to create an external GUI perhaps with JAVA or any ...
1
vote
1answer
23 views

How to save selected features from a postgis database into a new mini database

I have a postgis(v2.1.3)/postgresql(v9.3) database with geometry (geom1, geom2, etc.) and attribute (attr1, attr2, attr3, etc.) tables. The attribute tables are linked to the geometry tables using ...
2
votes
0answers
44 views

Building a ol3 webapplication with dynamic content and user registration

My setup: currently i'm using a postgis database, get it with a geoserver and display it with openlayers 3. I use the wfs data to display the features in clusters and i'm able to edit them with wfs-t. ...
0
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0answers
14 views

Do you have some reference to create WebGIS? [duplicate]

I need to create a webgis for my thesis. My thesis is create webgis with ms4w and mapfish as framework. I have trouble to show my map. I load map from postgis. So, I need some reference to continue my ...
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votes
0answers
57 views

How to compute “how many points present in each square mile area”

I am using postgressql. I am searching psql command - to find out number of points that lie in every square mile of an area. the SRID is 2263.and I have some information: Extent West -74.257159 East ...
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0answers
42 views

QGIS shapefile layers to database geometry type [closed]

I have opened Arcgis shapefile with QGIS. And I used QGIS database manager tool to create table and import data to postgresql database. Database manager is creating and importing success. But there is ...
1
vote
1answer
23 views

Is there a way to configure QGIS to prevent the st_extent call when adding a PostGIS table?

I'm trying to add an extremely large table with a points geometry field to QGIS and QGIS appears to hang. After some investigating in the postgresql database, I tracked it down to a st_extent on ...
0
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0answers
33 views

pgRouting with my bus network and select the best of the available routes?

so here's the case: I have been using postgresql/postgis, openlayers and pgrouting to create an online application that selects and visualizes the best of the availabble routes. My problem is though: ...
2
votes
1answer
81 views

How can i use Kriging inside a Postgis database?

i use a postgis database with temperature data. I want to use a spatial interpolation method but not the supported IDW Method. I need to use the kriging Method. Problem is that its no a part of the ...
0
votes
0answers
23 views

pgRouting 2.0 shortest path with pgr_dijkstra returns an empty result

I've been trying to automate shortest path finding for a list of points (on pair at a time) using the OSM road layer for Sri Lanka. I'm using pgrRouting 2.0 and have followed the instructions here. ...
3
votes
1answer
53 views

Postgis is Broken after installing Nominatim

I followed Nominatim Tutorial to install PostGIS and after that I can't access PostGIS at all I already trying reinstalling and installing everything over and over again with no success. Everytime I ...
0
votes
1answer
65 views

How to calculate the optimum bus route using pgrouting?

My setup for my web page is OpenLayers, Postgresql/postgis and pgrouting. What I do not understand is how I am going to do the routing.I have read many tutorials but I don't understand what my next ...
2
votes
0answers
45 views

Inserting coordinates from Google Maps into a Database

My question is pretty basic. I am using Android Google Maps to take the coordinates off a location on the map and I want to insert it into a PostgreSQL database. I know I have to use PostGIS but how ...
1
vote
1answer
27 views

Search Points within Buffered Polygon with PostGIS

I have a table of boundaries as polygons and another table of peaks as points. I want to find the points that are within the polygons and the polygons are extended with a buffer. What would be the ...