Tagged Questions

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

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0answers
31 views

Postgis - Split linestring between point A and B

I need to find the different trajectories between point A and B. In the image is possible to see 2 differents trajectories. The way i use to calculate them is: Found the min time and the max time (in ...
2
votes
1answer
35 views

View with sequence in QGIS 2.4

In postgres, I created a view with a sequence nextval() to have an unique id (called vid). I tried to vizualise this view in QGIS but it failed. It seems that nexval() causes some issue according to a ...
2
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1answer
61 views

pgsql2shp ERROR: incompatible mixed geometry types in table

I have multi-linestring in .shp files and I split the lines with postgis, but that result is only geom column. It does not works with shape file exporter error: incompatible mixed geometry types ...
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0answers
36 views

How to work with gdb from c#?

I have installed PostgreSql 9.3, PostGIS(last version) and Npgsql. I have geodatabase(tmp.gdb) how to make conection for this DB from c#? And how to connect this DB to PostgreSql? It possible to ...
-1
votes
1answer
59 views

US Census Geocoder returns different city that TIGER Shapefile data

When I geocode an address using PostGIS+TIGER 2013 I get a different city than what Census Bureau Geocoder reports. The Long/Lat are identical in both cases, but the PLACEFP is different although both ...
-1
votes
1answer
30 views

PostGIS ST_Transform question

I have a query that returns the extent of a polygon. "SELECT ST_Extent(geom) FROM nct_cov WHERE prop_name = 'SLATE HILL'" It works fine, however I want to transform it using ST_Transform, however ...
0
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2answers
44 views

Postgis: Point-in-polygon check + feature attributes inheritance

I have two tables in Postgis 2.1 database: Polygon features with a reach attributive information; Regular point grid; I would like to get a SQL query returning the regular point grid with ...
0
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0answers
10 views

OpenLayers gx_geocodercombo returns syntax error

I try to implement a gx_geocoder combobox... { xtype: "gx_geocodercombo", hideTrigger: true, emptyText: 'Enter address (streetname housenumber municipality)', width: 350, layer: ...
1
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1answer
28 views

Mapnik tiles have latitude distortion, projection issue?

I'm trying to work out a kink in setting up mapnik-node. My geos are in postgis, and I allllmost have them rendering properly, but my GIS experience is lacking so I can't seem to determine why this ...
4
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0answers
84 views

Focal Statistics for Special Neighborhood

I'm looking to calculate focal statistics for each cell of a raster, within a neighborhood of a specified criteria. Background - I have three binary rasters, each representing a single vegetation ...
2
votes
2answers
57 views

What is the recommended workflow for using TileMill and OSM?

Using osm2pgsql, I imported an OSM extract into a Postgres database. Then I made a layer in in TileMill that contains the data from Postgres. The map was exported to a MBTiles file. At this point, all ...
3
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2answers
42 views

How to compute weighted centroids in PostGIS?

I have a group of points and each point has an associated count value. How can I calculate the centroid of the group weighted by the values associated to each point?
2
votes
1answer
36 views

Interpolating mobile signal data

I have collected the signal strengths for the mobile operator at some places in my college campus. Now I want to spatially interpolate this data for the entire campus. I am using PostGIS. I am ...
3
votes
1answer
496 views

What does “foo” stand for in this PostGIS command?

The help page for the PostGIS function ST_PixelAsCentroids has this line of code as a usage example: SELECT x, y, val, ST_AsText(geom) FROM (SELECT (ST_PixelAsCentroids(rast, 1)).* FROM dummy_rast ...
3
votes
0answers
46 views

Postgis database query optimisation

I have a set of rasters in DTED format which I load into postgis database using raster2pgsql command line tool. Each of rasters is simply stored in a row and described by rid and a value of raster ...
1
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3answers
37 views

problem to use openstreetmap data file with pgrouting2.0 on PostgreSql9.3

I'm a newcomer on pgrouting, and I want to test its functionalities. I've installed and configured my computer with Postgresql9.3, pgrouting2, and PostGIS. I've downloaded from openstreetmap the ...
1
vote
1answer
41 views

How can I render the postgis layer to the openlayers map viewer?

I have a postgres table which is storing the dynamic GPS point data. The geom column has been created. Is it possible to render the last 10 mins GPS data to the OpenLayers map? Is there an example? ...
1
vote
1answer
47 views

PostGIS get geometries within a radius of n meters using WGS84 [duplicate]

select * from zones z where st_intersects(z.geom, st_Buffer(ST_SetSRID(ST_Point(2.336031, 48.863172), 3857),1)); It looks like the 1 in the st_buffer is being interpreted as degrees, I need to find ...
0
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0answers
17 views

PostGIS raster write support in R

I want to push/write some generated raster layers to my postgres database directly in R. In theory this could be supported by the rgdal package, but sadly it isn't. In the latest version only copy, ...
1
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0answers
59 views

What is wrong with my WFS-T protocol setup?

So I want to transfer some Vector Layer Features from javascript code to my geoserver and then to postGIS, my code looks like this: saveStrategy = new OpenLayers.Strategy.Save(); ...
2
votes
0answers
51 views

How to get user and password of a PostGIS layer

I wonder if it is possible to get the user and password for a PostGIS database if they are stored in the PostGis connection information. I get the connection information at the moment from the ...
1
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2answers
60 views

Viewing large set of polygons in PostGIS using OpenLayers?

I am prety new to GIS. I have set up a postgis database with al large dataset and a openlayers front-end to display it. But since the dataset is getting prety big I am looking for a way to only load ...
0
votes
1answer
29 views

Delete all data from a PostGIS topology

I need to delete everything (faces, nodes, edges, anything I'm not thinking of) from a PostGIS topology, but I want to keep my database schema (schemas, tables, columns, sequences, etc.) intact. Is ...
0
votes
1answer
39 views

selecting elements of a specific geometry type in PostgresSQL/PostGIS

I was reading a postgis tutorial and noticed that unlike working with shapefiles, one can actually store different types of geometry in postgres. In a table created with multiple geometry types, the ...
2
votes
1answer
38 views

What are the PostGIS Raster Constraints used for?

My question is quite basic, but I have not found a simple explanation of why raster constraints are useful. I have worked with rasters in PostGIS for a while but only recently I realized that I do ...
1
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1answer
74 views

How to change the postgresql table to support postGIS?

I have a postgresql database which there is the table have lat & long columns. The postgresql does install the postgis extension. My question is how can I change the table with lat & long ...
0
votes
1answer
42 views

How to load postgis raster layers into R?

It is easy to get Vectorlayers into R from a PostgreSQL+PostGIS solution. library(rgdal) dsn="PG:dbname=plots host=localhost user=test password=test" plots = readOGR(dsn,"Plots") But how to do the ...
0
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0answers
37 views

numeric issue while loading floating point-valued GeoTIFF into PostGIS

I am trying to import a floating point GeoTIFF image into PostGIS (2.1), using the following command: raster2pgsql -s 4326 -I -M -F -C tif_dir/*.tif public.map | psql -U postgres -h localhost -d ...
0
votes
1answer
75 views

How to transfer a WKT string from OpenLayers to Geoserver or PostGIS?

Supposing I have created a Vector Layer in OpenLayers and then transformed it to WKT or GeoJson, how can I export it from OpenLayers, and possible import it to PostGIS or GeoServer?
0
votes
0answers
71 views

Importing a Raster into PostGIS 2.1 (Windows 7)

I am trying to learn how to import rasters into PostGIS (2.1). I have read through all the material I can find on doing this and know that the recommended tool for this is the raster2pgsql tool. I ...
1
vote
1answer
43 views

Loading raster in postgis and link it with an existing table

Relatively new to PostGIS and I am currently exploring the options to make one of my PostgreSQL Tables spatial. Essentially I want to store a raster object in a table that also contains essential ...
1
vote
1answer
94 views

How to migrate Postgres table having Lat Lon columns to an existing PostGIS database?

I am having Postgres database table with Lat Lon columns (degree, minutes, seconds) as shown below : CREATE TABLE population ( id double precision, idno text NOT NULL, place text, state text, ...
3
votes
1answer
72 views

How to snap a GPX-track to a road network?

I want to snap the GPX-track to the road network as the image below shows. I found out, that "Hausdorff Distance" is exactly what I need and that it is usable with PostGIS. But unfortunately I have no ...
1
vote
1answer
77 views

How to transfer layer data from OpenLayers to PostGIS database or QGIS?

Supposing I have a created some layers in OpenLayers containing only Geometry Points, how do I transfer my data to a postGIS database? Is there a way to turn pure javascript/openlayers to a table in ...
2
votes
0answers
62 views

How to plot heatmap/locations in Geoserver & Openlayers map from the Lat/Lon data of PostGIS table?

I am using Geoserver, Openlayers, PostGIS for Geospatial web implemenation. I have an Indian map shape files for States, Districts, Talukas. I am able to generate a map with states, districts, ...
1
vote
1answer
359 views

Why use a database when you can have all of your data in javascript/openlayers?

I have a really simple and basic question. First of all, I have to mention that I am pretty new to web applications and GIS. I am working on a web application using Openlayers, Postgresql/postGIS and ...
1
vote
1answer
13 views

Close linestring to linering in PostGis

is there a function which closes a linestring to a linering? I couldn't found such a function in the documentation. Thanks.
1
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0answers
31 views

Comparing and updating two large tables

I'm using CartoDB to sync the status from tables using a common ID on each one. The problem I found it's the tables are too large, over 29k rows. Here is the query I'm using and the gives me an ...
0
votes
2answers
51 views

Installing TIGER geocoder

I am trying to install the tiger geocoder for postGIS. I am using the 2.1 version of postGIS on Windows 7. I am using this set of instruction to do so. I am confused by what they mean be edit the ...
3
votes
1answer
40 views

Connection trouble GeoExt to Geoserver Layer

I'm so sorry for my english, it's not the best. I'm trying to modify my postgres geographic table with this code: Ext.onReady(function () { OpenLayers.ProxyHost = "proxy.ashx?url="; var ...
2
votes
2answers
51 views

How to convert a raster to lat/lon points

I am working with the tri.txt (terrain ruggedness index) file from this paper: http://diegopuga.org/data/rugged/ I've uploaded the raster data from the file into ArcMAP and now have it as a .tif ...
6
votes
1answer
76 views

one label for two-lane roads (osm, qgis, postgis)

I labeled my osm-lines-layer (PostGIS) with symbols for primary roads and motorways. While the symbols for the primary roads are well placed - with enough distance between each - the two-lane motorway ...
1
vote
3answers
45 views

Disconnect QGIS from database without closing the whole program

I'm making PostGIS queries to a GIS database from python and I'm using QGIS to visually check the results of my queries, but every time I want to run a new query I have to close QGIS because it keeps ...
1
vote
1answer
38 views

How to create a routable network with PGRouting

I have two sets of data Table A: Stations - contains postal code (which I can convert to lat/long), name and code. Table B: Connections - contains a possible list of connections including source, ...
6
votes
2answers
82 views

Similarity between two or more trajectories

I have the data of trucks (http://www.chorochronos.org/). This data are gps coordinates of multiple trajectories of trucks in Athens. I have to calculate the similarity between the trajetories, in ...
1
vote
2answers
68 views

take from multilinestring the start & end points

I have to use the A* algorithm and my geometry is in multilinestring and i want to take stratpoint(x1,y1) and endpoint(x2,y2) . I use this queries but the colums after the execute is still empty ...
2
votes
0answers
36 views

OpenGeo: GeoExplorer cannot upload shapefiles into PostGIS

I have installed OpenGeo 4.1 on Ubuntu Linux 12.04 following the official instructions. I then followed the tutorial Load your data with GeoExplorer. I was able to zip and upload a few shapefiles. ...
1
vote
1answer
57 views

Query to get convex hull

Is the below query correct to get a convex hull shape: DATA "the_geom from (select ST_ConvexHull(ST_Collect(the_geom)) As the_geom FROM xyz) as foo using unique id using SRID=XXXX"
1
vote
0answers
26 views

Error in querying data

I have a mapserver file as below , I get blank page with no map executing this query: NAME var DATA xyz STATUS ON TYPE POINT DUMP TRUE ...
3
votes
0answers
52 views

Create a Shape file from Sql dump file

I am trying to map data by querying a table called xyz. I need to show the the_geom data on the map. I have below query in my mapserver .map file: DATA "the_geom from xyz using unique id using ...