Tagged Questions

0
votes
0answers
41 views

QGIS Plugin Development - Displaying Data from a feature

I want to display data based on the feature currently selected/clicked on. I am following a tutorial from http://www.qgisworkshop.org/html/workshop/plugins_tutorial.html. It initially shows you how ...
0
votes
0answers
18 views

Loading raster from PostGIS DB into QGIS: succeeded yesterday, fails now

I have a PostgreSQL(v.9.2)/Postgis(v.2.0.3) database which includes raster layers (added through raster2pgsql). To open them in QGIS (v.1.8.0-Lisboa), the "Add Postgis layer" menu will not work; ...
3
votes
2answers
93 views

What Is The Ideal Workflow To Map (British) Postcode Territories

I'm looking for the best workflow for mapping postcodes and calculated territories, but being relatively new to mapping I'm struggling on a few details and also the best practices for displaying these ...
1
vote
0answers
56 views

How to get Lon/Lat values from the postgis raster type column

I have a tiff raster in my PostGIS 2.0 database. I want to get the value lat/lon and extra data like temperature from the raster type column in postgis table. I want the table with columns ...
-1
votes
1answer
61 views

QGIS and Python - create line with multiple points in postgis

How can I create a line, with Python functions, with many points that are records in Postgis? Thank you
0
votes
1answer
42 views

Cant Instal psycopg2 on mac 10.8.2

I know there Have been a lot of similar questions asked but none address this issue as I far as I can tell. When I am trying to install the sextante plugin, or run PostGIS Manager in QGIS I receive ...
2
votes
0answers
47 views

Installing knn on PostgreSQL for windows

I am trying to install the extension KNN for clustering as an extension on my PostgreSQL database. I have downloaded the file http://www.pgxn.org/tag/analysis I found instructions on how to ...
5
votes
1answer
127 views

How to implement Spatial Autocorrelation using QGIS or PostgreSQL (or any free application)?

I am a total newbie on the GIS scene so I hope this is not a stupid question. I have two layers in a PostgreSQL database. The first layer contains points where events happened in Europe. The second ...
1
vote
1answer
53 views

Does each road segment need to be digitized into a separate entry for a road network?

I am trying to understand this code in pgRouting for creating topology: CREATE OR REPLACE VIEW road_ext AS SELECT *, startpoint(the_geom), endpoint(the_geom) FROM road; CREATE TABLE node AS ...
0
votes
0answers
42 views

What are the rules for digitizing roads for creating a road network?

I want to create shortest route tool using pgRouting. But I digitised roads in a random manner. Shall I need to give a separate row for each road segment?
0
votes
0answers
61 views

QGIS SPIT errors loading shapefile into PostGIS

With QGIS 1.8 on Windows 7, I just installed PostgreSQL / PostGIS and tried to load my first data into it, a shapefile using SPIT, but failed: ERROR: Geometry type (Polygon) does not match column ...
0
votes
1answer
70 views

How can i select many rows from a table?

I want to create an action that select many rows from PostGIS table to show many lines in QGIS. How can i select many rows from table with python to add these rows in a layer? Thank you
0
votes
2answers
94 views

I can't export in QGIS a Shape file to PostGis

When I try export a pipe network shape to postgis i get this error: Problema inserindo feições do arquivo: C:/PP/gvSIG_Projects/Shapes/Abastecimento/QGIS_VATROCOADUTOR.shp Ocorreu um erro no banco ...
3
votes
1answer
115 views

How to import QGIS Raster into PostGIS

I have created a IDW heatmap using QGIS 1.8.0 and need to import the raster into PostGIS 2.0.1. QGIS saves the raster layer as a .asc file. How do you import the raster into PostGIS as a Raster? What ...
1
vote
0answers
54 views

Creating polygons for a choropleth map using PostGIS

I have a grid of points, each with a value to it as shown in the image below. The data was retrieved from PostGIS and rendered in Quantum GIS. The final result should be a polygons of a choropleth map ...
0
votes
0answers
55 views

How to fix 'pgsql2shp: command not found' in PostGIS Query Editor Plugin?

I'm using QGIS 1.8 on Macbook Pro running OSX 10.8.3 and I am having difficulty using the PostGIS Query Editor plugin. When I try and execute a query in this plugin I get the following error in the ...
5
votes
3answers
97 views

What is the easiest one click install method for PostGIS and it's entire dependencies?

For someone new to database servers and their dependencies, what is the easiest assured way of installing PostGIS on a machine with no other software beyond what comes with its operating system? I'd ...
2
votes
3answers
70 views

Connnect to PostGIS db using QGIS - when not on localhost

I"m just getting started with PostgreSQL/PostGIS db (v9.2) and I'm wanting to connect to db while not on the localhost using QGIS. I've been able to connect successfully on localhost, however I'm not ...
1
vote
0answers
89 views

How can I map data points to OpenStreetMap (OSM) line data?

my goal is to filter measuring points of vehicles by mapping them to streets. So I could filter out all the false data located in fields and rivers and so on. I imported my data into a PostGIS ...
1
vote
1answer
51 views

pgRouting：how to use reverse_cost？

I add a new column, naming it "reverse_cost", and give it the same data in the shape_leng column. But as I run the shortest path algorithm in pgadmin, I got an error message. here's my sql code ...
3
votes
2answers
87 views

Problem loading PostGIS (Postgres) View layer in QGIS

Why is Postgres user XX via command „Add PostGIS Layers“ in QGIS enabled upload only View tables which owns? Or how to achieve it to the user XX via PostGIS can load View table which owns the user YY? ...
0
votes
1answer
81 views

Aggregate points with same values to polygons

I have a shapefile with 2M measurement points (each measurement point has a resolution of a 1/10). How can I aggregate points around each other if and create polygons out of it? They do not have to ...
2
votes
2answers
69 views

merging layer stored in PostGIS

I have a bunch of layers stored in PostGIS that I want to merge. I have spent quite some time investigating various approaches but I ket tripping over getting the GIDs to update properly. In the end ...
7
votes
3answers
201 views

Howto setup and use a remote GIS workstation (QGIS,GRASS,PostGIS)?

I'm using QGIS (and sometimes GRASS and PostGIS) on my 2009 MacBookPro for my thesis project. I was wondering (during an endless batch generalizing in QGIS) if I can set up a server so I can work from ...
9
votes
1answer
126 views

How to find the buildings (polygons) a user can see from a given location (point) and orientation (angle range)?

I would like to retrieve the set of buildings I can see from a given location (point -lat,lng) and orientation (interval of angles) + certainly with a given depth (e.g. 100 meters). Ideally I would ...
0
votes
2answers
85 views

Query for Creating a buffer around a particular point

I am working on a project for ambulance management using GIS. using Qgis,Postgresql,Postgis I am finding it difficult querying using St_dwithin as well as St_buffer. My aim is to find any hospitals ...
2
votes
1answer
68 views

Cannot find my schemas in QGIS's “Add PostGIS layers”

When I connect to my PostGIS database using QGIS's Add PostGIS Layers, I see only public topology pg_catalog information_schema My other schemas that I have created are not shown here. Anyone else ...
2
votes
0answers
68 views

Storing features in PostGIS and then creating layers using queries

I have a whole set of line segments or tracks that represent real tracks or, in some case, boundaries between areas. These segments form a network of lines on the map. I have a number of GIS layers, ...
0
votes
1answer
48 views

problems about setting pgrouting with QGIS under windows

I followed this website：A Beginner’s Guide to pgRouting and now facing some problems. I finished steps before "Creating a routable road network", and open QGIS 1.8, click the PostGIS Manager plugin, ...
0
votes
2answers
62 views

Manually add a new point to PostGIS table [duplicate]

I did accidently delete a table row - or well, in fact a whole subway station. My attempt to solve the problem was this PostGIS function: ST_GeomFromText('POINT(coordinates)') But then PostgreSQL ...
1
vote
0answers
113 views

View PostGIS geometry in QGIS

I am a newbie to GIS systems so please be patient. I have a PostGIS database set up with a spatial data table. One of the columns is of Geometry type and contains Points with SRID 4326. I want to ...
2
votes
2answers
68 views

Is there a way to visualize a convexhull in qgis 1.8 lisboa?

There is no way to visualize a convexhull in qgis 1.8 lisboa? I have tried following views in Postgis 1.5 I was told to use an id column to publish it in Qgis. If you not use an id column, u cannot ...
0
votes
0answers
52 views

QGIS cannot view raster loaded to PostGIS through raster2pgsql

I tried to load a raster GeoTIFF image to a PostGIS database using "raster2pgsql" following the OpenGeo Suite Manual. The command I used is: C:\>raster2pgsql -s 4283 -I -C -M "C:\Program ...
0
votes
1answer
50 views

PostGIS Manager Load Error

I am using the PostGIS Manager Load data to PostGIS tool on a Windows install and am getting the following error: Something's wrong: ["'shp2pgsql' is not recognized as an internal or external ...
0
votes
2answers
87 views

QGIS: using postgis can I define a layer using sql?

I have a vector layer (call it master) that is stored in postgis and consists of a number of line segments. I also have a collection of sub layers that consist of subsets of the master layer. I can ...
2
votes
2answers
86 views

How do I plot data stored in an attribute table (really in a database) in qgis

I have a csv of UK postcodes from Ordnance Survey that looks like SE1 0AA,10,531869,179427,E92000001,E19000003,E18000007,E09000028,E05000536 When I import to QGIS using 'Add Delimited Text Layer', ...
1
vote
1answer
48 views

segment lines according to point using pgRouting?

I'm working on postgresql and I am trying to create table to generate graphs. I have a table that contains all the objects of a city (points) and another contains the city street. My goal now is to ...
2
votes
1answer
73 views

QGIS, Postgis: Is it possible to create a new postgis layer?

Situation: I have a postgis vector lay that has lots of line segments (the features). I want to create a set of new layers each of which contains a subset of the features of the original layer and ...
2
votes
1answer
38 views

QGIS: Making changes to vector layers stored in PostGIS

I have a vector layer stored in PostGIS. I split several lines in the layer and simplified others by removing vertices. When I tried to save the changes to the layer I got postgres more postgres ...
2
votes
0answers
28 views

Automatic insert of project name into database

For every layer I've a field in my postGIS database that should be filled with the name of the current project and today I do this manually. Is there a way to do this with the Commands that can be ...
0
votes
0answers
44 views

Problem in joined table

I test to join two postgis layers, one geometryc and other without geometryc data. Data are loaded properly in qgis (1.8 in Osgeo4w distribution) and the joins seem been done properly but when i try ...
2
votes
1answer
119 views

Connect to PostGIS using SEXTANTE in QGIS

I have a localhost PostGIS database that I would like to use with SEXTANTE in QGIS. I can connect to the database just fine using "Add PostGIS layers...", but when I try "PostGIS execute SQL" in ...
0
votes
0answers
193 views

QGIS 1.8.0-Lisboa DBmanager (OSx) can't connect to remote PostGIS 2.0.2 database (Debian)

The PostGIS database is remote but I have made changes to the Postgresql config files and can access it remotely via pgadmin. When I open DBmanager in QGIS I see a note on the bottom that says ...
2
votes
1answer
78 views

PostgreSQL gid copy problem in Quantum GIS

When I enter new elements (features) in another Postgres layer, I can do it in two ways: Drawing new element(s) (with 'Add feature') which I do rarely or Copying (or cutting) some elements from ...
0
votes
1answer
95 views

Postgresql on Ubuntu Server and QGIS [closed]

Complete newbie... I taught myself the basics of GIS on the job with ArcGIS 9.3. I have been plating with QGIS and have gotten the basics down on both. I am not well versed in the terminology related ...
4
votes
1answer
83 views

QGIS field calculator and Postgres permissions

I’ve given user x the following GRANT ALL ON ALL TABLES IN SCHEMA y TO x; GRANT ALL ON ALL SEQUENCES IN SCHEMA y TO x; GRANT ALL ON ALL FUNCTIONS IN SCHEMA y TO x; However in QGIS they dont have ...
1
vote
1answer
55 views

Keep .gdb structure to postgresql + PostGIS (Feature dataset)

I have a .gdb file with a specific structure. I will extract all shp files for uploading to a postgtresql db. But I want to keep the structure of gdb. How can I keep this structure to ...
1
vote
1answer
128 views

How to create routable network by pgrouting with assign_vertex_id?

I'm trying to create the routable network as per http://underdark.wordpress.com/2011/02/07/a-beginners-guide-to-pgrouting/and use assign_vertex_id. Do I still need to create the node table? How would ...
2
votes
0answers
85 views

Adding polygon to existing database column

I've built a database with postgreSQL with a few geometry columns. When I add some data to my non-geometry columns, I can see them in QGIS when I connect to my DB using postgis. Now, I want to add ...
0
votes
1answer
159 views

Creating routable network table in PostGIS

I am trying to create the routable network table, as per http://underdark.wordpress.com/2011/02/07/a-beginners-guide-to-pgrouting/. Everytime I do it in PostGIS extension, QGIS crashes. The area is no ...

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