Tagged Questions

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

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37 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
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1answer
82 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
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0answers
24 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
58 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
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1answer
73 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
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0answers
48 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 ...
0
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1answer
33 views

Spatial query to make view

I've got two tables which I want to combine and enrich with each others data. I'm getting stuck on the join part, as this needs to be done via a spatial query. First the table structure: a table with ...
0
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1answer
67 views

Google Maps Api , PHP, Javascript and Postgresq-Postgis

I'm trying to make a web application, where I take the start/end city from a text box, geocode the city, use the coordinates to query my database in PHP, and return the features to be drawn in the ...
0
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1answer
31 views

Can't add a postgis layer in tilemill (symbol shown grayed)

I want to add a postgis layer to a tilemill project but the symbol is shown grayed and I can't select it (shown on the picture below). I followed this instructions.
0
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1answer
46 views

st_startpoint(the_geom) returning empty values

When I upload a shapefile to PostgreSQL using the QGIS tool I can create the routing topology following this tutorial without any problem. But when I use the PostGis Shapefile Import/Export Manager ...
1
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0answers
29 views

Postgis geocoder size and performance

I have installed Postgresql 9.3.5 and Postgis 2.1.2 on a 16Gb Ubuntu 14.04 system. (1) If I load all the states TIGER data, using the scripts provided in Postgis, how big will the database be for the ...
2
votes
1answer
28 views

How to transform this PostGIS type of projection to EPSG:900913 in OpenLayers?

I have transferred this kind of projection from this type(which I don't what type it is): 010100000054E077E6F8F33640FD87F4DBD7AD4340 to EPSG:900913. I have the points which are in the above format ...
0
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1answer
23 views

Selecting PostGIS objects out of given distance

I need to select by SQL querry objects that are further than 100m from specific type of road. For selecting object that are in given distance there is ST_DWithin but what to do in this case?
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0answers
45 views

From a point find the closest line [duplicate]

I tried to find a LineString from my table road the nearest line to a point I give, but it is return me all the table SELECT gid, ST_Distance(ST_Transform(ST_GeomFromText('POINT(39.240443 ...
2
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0answers
25 views

Diminishing performance of gdal_polygonize in a python subprocess for GRASS to PostgreSQL

I have written a python script to polygonize GRASS rasters into a PostgreSQL database using the gdal utility gdal_polygonize: sub.call('gdal_polygonize.py -8 gdb/quercus/{0}/cellhd/{1} -f ...
0
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0answers
34 views

How to import NetCDF to PostGIS (or GeoTIFF)

I was wondering if there are some online examples/instructions for importing NetCDF files into PostGIS raster images? I looked around, and found this related GIS SE question. However, the answer only ...
1
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0answers
29 views

Read and Write data with Open Layers3

I'am currently using postGIS/geoDjango/OL3 I need the capability for a user to drop a point on the map, and store that in my database. When any user returns, that point will be shown on the map. ...
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2answers
43 views

How can I measure(length) line of segment in postgis?

This is my first question. I wonder that, how can I get length of line's segment? Yellow line is my road. blue Points are my start and end points. So I want to measure point1 and point2 between ...
0
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0answers
28 views

Replace for Tilecache?

I tried to use Tilecache with my mapserver/openlayers/postgis/cygwin configuration, but no success so far, I just got tired of keeping digging in the whole system to get that thing working. So, could ...
0
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0answers
33 views

How to fix scaling mismatch of shape file layer & PostGIS table Lat/Lon data layer for India Map in Geoserver?

I have generated India map in Geoserver using the shape files downloaded from "www.diva-gis.org/gdata" site. Now, when I expose my PostGIS table layer having Lat/Lon data for Indian cities, on top the ...
5
votes
1answer
101 views

What controls the direction of TopoGeometry Linestrings?

In PostGIS, what if anything controls the direction that topogeometry LINESTRINGs will have when converted to geometry? It doesn't appear to be the order in which the edges are listed in the call to ...
1
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0answers
42 views

What does it mean when I get rows executed, but with no resulted table?

While applying the following tutorial: http://anitagraser.com/2011/02/09/creating-catchment-areas-with-pgrouting-and-qgis/ utilizing vector network which has been tested (and demonstrated ...
2
votes
0answers
28 views

Why pgRouting GUI panel may not work in QGIS?

What could be the reason behind the mal-functionality of the pgRouting Layer GUI panel? In order to route shortest path via dijkstra function code I'm able to conduct the task using the following ...
0
votes
2answers
88 views

Using AJAX to run PostGIS SQL statements and display results via GeoServer

I am learning Web GIS, and I can't find a good example that gives a big picture of a web interface of running spatial analysis using PostGIS. What I am looking for is a graphical/GIS version of ...
0
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1answer
12 views

return state of point from postgis / mapnik pgsql db

I realize that I can confirm whether or not a point lies within a state like this: SELECT ST_Contains(poly,pt) As testr FROM ( SELECT ...
1
vote
1answer
27 views

PostGIS Unknown colormap keyword

I'm working with thematic maps with ST_ColorMap function smoothly until I try to create my own thematic map(colormap). WITH canvas AS ( SELECT ST_Raster( ...
2
votes
1answer
51 views

Export PostGIS line to AutoCAD with graphical direction information

Some time ago I managed to export from PostgreSQL to AutoCAD DXF format a line (LINESTRING) using ogr2ogr program with a PostgreSQL Query, and it works (I can visualise it by the QuantumGIS). Now I ...
1
vote
1answer
38 views

How to export a postgis table to a pbf file?

I need a tool like osm2po or osm2pgsql but that does the opposite thing, convert a postgis table to a pbf file. I think qgis can do this but I can't find that option.
1
vote
1answer
29 views

Adding PostGIS query layer says Query class name is invalid?

I am having issues with adding postgis query layers in ArcMAP 10.2.2.3552, not doing anything special just adding a layer, this works in 10.2.1 so I don't know if its a bug or something Also this ...
5
votes
2answers
72 views

How to draw radius of a circular point buffer using PostGIS

I have generated circular buffers of points in a shapefile. The generated circles and points share a common ID/key, say pt_id. My question is Is it possible to use PostGIS to generate a third layer ...
1
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0answers
34 views

Issues with QGIS WFS editing/PostGIS rendering

I want to be able to view and edit spatial data within a postgis database. I have tried using a WFS with Geoserver - but constantly get 'Empty Response' error and the Network log says the request ...
0
votes
2answers
72 views

Converting coordinates to 4326 for Google Maps.

I have a MultiLinestring, example coordinates, (698745.50201423 4210011.04002000) and I would like to convert them to something like (24.362 42.458) to use in Google Maps. When I try to get the SRID ...
0
votes
1answer
24 views

No results for PostGIS TIGER geocoder extension

Similar to this question, my TIGER geocoder extension in PostGIS isn't returning any results. It seemed to all install correctly, so I imported DC, and: psql -d geocoder -c "SELECT g.rating, ...
2
votes
1answer
65 views

QGIS select reversed geometries

I have a road network and a geometry for each road direction. One Geometry from A->B and another Geometry from B->A. This geometries are covering each other. Is there a tool available in QGIS to ...
1
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0answers
30 views

Error creating a spatial database. ERROR

I have been trying to get Postgis set up for a while now, I am stuck on one error and have not found a solutions yet. This is on Ubuntu 14.04.1. I am trying to run: CREATE EXTENSION postgis But am ...
1
vote
0answers
28 views

Invalid join selectivity error in postgis 2.1.3

I have 2 tables, one for points and one for polygons. I want to find points falling within theese polygons, so I quered: select p.id, l.id from points p inner join polys l on st_contains(l.geom, ...
1
vote
1answer
34 views

How to modify a PostGIS function?

I wish to modify a PostGIS function ST_PixelAsCentroids. What is the best way to go under-the-hood of PostgreSQL/PostGIS functions and modify and customize them as you wish? I'm not hitting the right ...
-1
votes
1answer
47 views

Geocode as soon as PostGIS table is updated

I am trying to create a map such that as soon as I enter an address into PostGIS table, it'll automatically be geocoded (and published in geoserver). The only way I could think of doing this was using ...
0
votes
1answer
39 views

PostGIS point st_within() polygon = false

so geoserver shows me a red dot within a blue polygon, i thought postgis can tell me that fact by query. i tried the following statements without success, can anyone tell me what i did wrong? select ...
0
votes
0answers
28 views

Insert several gtfs feeds into the same postgis/pgrouting database

I want to import sevaral gtfs feeds into my postgis/pgrouting database so that I can route over all my gtfs feeds. The problem is that the sources / destinations ids of my gtfs are likely to ...
0
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0answers
35 views

Apply raster contraints on single table with multiple files

I have a raster table (pre-created using CREATE TABLE) containing multiple individual raster files that I append piece by piece to a final table. The table itself is in its own tablespace 'gisdir' and ...
2
votes
1answer
72 views

Reading postgis geometry with shapely

I am doing a small-scale workflow in ipython notebook with geopandas and shapely, pulling a bunch of geospatial data, sometimes from shapefiles, sometimes from postgis (where more expensive processing ...
0
votes
2answers
145 views

Unable to connect to PostGIS databases after Mac OS X Yosemite upgrade

I upgraded to Mac OS 10.10 Yosemite and am unable to connect to PostGIS databases (PostgreSQL version 9.3 and PostGIS installed from KyngChaos). Typing psql my_database returns this message: psql: ...
1
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0answers
11 views

PostGIS 1.5 libstdc++ error

After some package updates on my Debian machine all my database queries involving postgis functions or types are returning: Error message from server: ERROR: could not load library ...
1
vote
0answers
30 views

Are there naming rules for direct connections from ArcGIS to PostgreSQL?

I don't have problem direct connecting arcgis to postgresql if my database name contains only letters, but when the name contains dashes or underscore e.g:"gisdb-dev", I receive an error when setting ...
0
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2answers
100 views

How to store lat/long in PostGIS database? [duplicate]

I have a bunch of points in a text file that are represented using lat long (116.3158516 39.9748016). I import them into my GIS enabled database and create trajectories using st_makeline() as ...
2
votes
4answers
67 views

How do you generate WKT from a graphic drawn on a map?

All, In order to do some quick analysis using SQL spatial, I'd like to generate spatial objects using the STGeomFromText / ST_GeomFromText function. With point data, I can do this by geocoding an ...
2
votes
1answer
68 views

Ideal file format for QGIS that allows mixed geometry types?

I have a spreadsheet for an archaeological project that is hosted on Google docs. This allows multiple contributors to edit and update the table as revisions and field data comes in. The table is not ...
0
votes
0answers
15 views

pgsql2shp converting nulls to spaces

Why does PGSQL2SHP convert null values to spaces when exporting a table? I would have expected empty strings in the shapefile (dbf).