QGIS is a user-friendly, cross-platform GIS application licensed under the GNU General Public License.

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2
votes
2answers
418 views

Manually Adding a Decimal Field to the Attributes Table

I am fairly new to QGIS and search as I might in the manual, training manuals and widely on the net I can't find an in-depth explanation of how to set up a Decimal Number (real) field in my attribute ...
7
votes
3answers
595 views

What are QGIS Arcpy Equivalent Functions for Update/Delete Row/Field?

I am trying to reprogram some scripts from arcpy to qgis (1.8 or 2.0) and there are some simple functions that I want to be able to redo but unfortunately documentation in qgis is lacking in certain ...
1
vote
0answers
233 views

Qgis libqgispython.so failed to load

I am using Qgis 1.8 and Python (on Ubuntu 12.10) for a couple of month now, but today i got suddenly the error Couldn't load Python support library: Cannot load library /usr/lib/qgispython: ...
1
vote
3answers
653 views

Why can't I open postgis layers in QGIS?

I've set up a table in PostGIS using OSM data (converted using osm2pgsql). I know this database is good, because I'm able to import it and work with it in TileMill, but whenever I try to interact with ...
3
votes
5answers
526 views

How can I count overlapping polygons, resulting in a new set of polygons?

I have 100 polygons in a GeoJSON file that partially overlap each other. I would like to produce 100 new polygons as follows: The area covered by any of the original 100. This is their union. The ...
1
vote
1answer
310 views

When is Qgis 1.9 being released

I've been working in the alpha of 1.9 for quite a while (because of doing bug reports) and I like it a lot. It's more than a year since 1.8 was released, so I wonder when 1.9 is expected out.
2
votes
0answers
107 views

QGIS - How to avoid -2147483648 value from imported CSV?

I am attempting to join a spreadsheet containing all the CIA Factbook Country Comparison Data (many columns) to the existing Natural Earth world countries shapefile. I followd the tutorial here, but ...
0
votes
0answers
109 views

QGIS layers not adding properly

using QGIS 1.8.0 lisboa on windows 7 pc adding vector layers and they are not adding properly they don't show up in the layers list but they are there when I happen to merge the the layers ...
1
vote
1answer
161 views

How to sum the values for bins with the same location?

I have two maps in csv form, each has a latitude, longitude, and value column. Since not all the positions in one map are in another map, is there any way in QGIS to display a new map which only shows ...
0
votes
1answer
390 views

Is it possible to override autoincrementing keys when QGIS inserts into SQLite?

I have a table, without any geometry, loaded in QGIS 1.8.0 (from OSGeo4W) via the Add Vector Layer option. The table resides in a SQLite/SpatiaLite database, and has a field named "id" that was ...
0
votes
1answer
350 views

How to batch merge rasters using FOSSGIS tools?

I'm working with QGIS 1.8 (gdal 1.9.2) and GRASS 6.4.3...but on Windows 7. I "just" want to merge my raster. I've got a folder with 50 GTiff raster from Lidar data. The aim is to merge raster ...
9
votes
2answers
520 views

Are there Desktop GIS alternatives to ArcGIS 10.X for topology and vector conflation?

Is there any options other than ArcGIS for Desktop for topological rules and automatic topology integrity enforcing in a Desktop GIS? I am looking for something that will automatically snap features ...
2
votes
1answer
161 views

QGIS custom form: 'dynamic' default value

I am trying to make a custom form in QGIS to smoothen the digitizing process. For this purpose, I put the Edit widget (Layer properties, fields) of one of the fields on 'value map', and I loaded a ...
0
votes
1answer
108 views

Draw lines for existing list of data

I have a csv file containing information for loads of lines (dates, road names, condition information, etc etc) but which have no geographical information (other than the association of road name) Is ...
4
votes
2answers
1k views

Setting the extent for a QGIS map using python

I am writing a stand-alone application in Python/QGIS that simply creates maps. I want to load vector/raster layers, set symbology, set extent At the moment, that is all! Currently I am just using ...
2
votes
0answers
111 views

How to fix ImportErrors when loading Python plugins in QGIS?

I have recently installed QGIS 1.8 in Windows 8. Although QGIS seems to be working fine, I cannot load plugins after their installation. Instead I keep getting this message: Traceback (most recent ...
2
votes
0answers
243 views

PyQGIS joining a dbf to a shapefile

I am trying to join a shp and dbf file using the PyQGIS API. The code I'll use is below: from PyQt4.QtCore import * vector1 = QgsVectorLayer("path to dbf file", "test1", "ogr") id1 = vector1.id() ...
2
votes
2answers
678 views

Merge lines with the same 'name' attribute on QGIS?

I have a shapefile with a few thousand lines, each is a street segment. I'd like to merge all features with the same 'streetName' attribute into a single attribute. I only really care about the name ...
1
vote
2answers
344 views

Can I prevent QGIS raster clipper from changing output cell/pixel size?

I have performed a DEM extraction using the clipper tool in QGIS 1.9.0 Master, using a mask layer, the original resolution of the DEM is 20x20 but in the resultant DEM the new resolution is ...
5
votes
1answer
193 views

How to convert a column of numeric IDs to letters?

I'm working with qgis 1.8.0. I divided a map into 500 features (small rectangles), and now I have the doubt if there is any way to change the ID of the attributes from numbers to letters? When I did ...
0
votes
0answers
81 views

How to add a field to a .zip shapefile?

I am exploring the possibility of using ArcGIS Online (Free Public Account and Explorer) with my new Global Studies students. (So far, the Free Public Account appears to be more user friendly and ...
1
vote
1answer
265 views

Connect not working for custom QGIS form

So I have a custom form for editting feature attributes. However, I can't seem to correctly disconnect and reconnect certain bindings. The init code is below and should work for any simple QT widget ...
1
vote
1answer
315 views

Qgis crash when I attempt to open ECW raster format.

I added Ubuntugis unstable repo and installed Qgis, libgdal-ecw-src, libecwj2-3.3 but still do not work. When I attempt to open an ecw file with Qgis it crash and tells me that there are problems ...
1
vote
1answer
106 views

QGIS Spatial Queries

I was wondering if I could do the following within QGIS: I want to update a column in my point layer with the attribute information from a specific column in a polygon layer - so I have a layer of ...
0
votes
0answers
31 views

QGIS Render shape when partially of screen

I am rendering a census area, a polygon the source of which is kmz file. THe shape only renders when the entire extent is visible on the screen. If I zoom in so some of the polygon extent is off ...
0
votes
0answers
56 views

QGIS Gazetteer Plugin connection to internal database

A few posts on here mention that the Astun QGIS-Gazetteer-Plugin could be adapted to reference a PostGIS database. Has anyone done this adaptation and could share it? I want to use a gazetteer stored ...
2
votes
1answer
70 views

cannot download 3rd party plugins in qgis

I want to download SDA4PP plug-in in QGIS. Unfortunately I cannot see the button to download 3rd party plugins, as indicated in the install instructions at that link. I am using this program on a ...
1
vote
2answers
394 views

Openlayers Plugin, Project CRS and Grids in Composer

Apologies in advance for the potential for this to be a duplicate question, I've had a good look, and I can't see a solution thatI understand well enough to help me. I have my project CRS set to a ...
1
vote
1answer
71 views

point shape file problem

I have a point shapefile which was created from a text file in Excel using the delimited text layer plugin in QGIS. My problem is that I am getting a point shapefile but when i try to insert this in ...
1
vote
1answer
26 views

Why do I suddenly get 'ERROR' as elements in my attribute table after doing a query in QGIS?

I was looking at an .osm file in QGIS using the OSM plugin; I was specifically looking at a country's lines layer. When I checked the attribute table just after opening the .osm, everything looked ...
1
vote
1answer
54 views

How does one install QGIS from previously downloaded OSGeo packages

I have downloaded the OSGeo Installer (on Windows 7 x64) and run it, selecting the Desktop Express Install option. All of the files were downloaded and the installer reported a successful install, ...
7
votes
1answer
2k views

Qt Designer and QGIS -

I am just trying understand how qgis and designer work together. From Nathan W's excellent posts I know how to create a user form and how to hook it to a qgis layer and also how to add validation ...
0
votes
0answers
59 views

QGIS: (Shapefile) Convert rings to fake-rings?

I hope I can make my question I posted yesterday clearer... sorry! Basically, I want to obtain the opposite of this: How to convert fake donut holes in polygons to real ones? Such polygons will ...
1
vote
2answers
379 views

How to extract features with specific coordinates from a ShapeFile?

I would like to extract a number of features from a ShapeFile which match with specific latitude/longitude values. I am interested if/how this can be done with QGIS and ogr2ogr. The output should be ...
0
votes
0answers
699 views

Create Voronoi/Thiessen polygons in QGIS around 3 points

Running QGIS 1.8.0 I have three bus compounds. I would like to generate Voronoi/Thiessen polygons around those three points. Following Voronoi/Thiessen adding an all school points will allow us to ...
0
votes
1answer
106 views

How to add information to an attribute table?

I'm working with qgis 1.8.0 and did the following: 1.-Divided my shapefile into 830 features (small rectangles). 2.- Added to my shapefile several points containing weather information using the "add ...
1
vote
1answer
2k views

QGIS - Export PDF map with georeferenced data [duplicate]

I am used to working with ArcMap but have been playing around with QGIS. When I export a PDF map with ArcMap, the PDF is spatially referenced. This is a handy tool, I can put the PDF map on my iPhone ...
0
votes
0answers
924 views

QGIS Plugins - DLL load failed: %1 is not a valid Win32 application

This is my first question so please go easy. I am trying to develop a Plugin for QGIS. I made my plugin using the "plugin builder", then compiled the .qrc and .ui files with PySide-rcc.exe and ...
0
votes
0answers
54 views

SEXTANTE Saga-grid normalisation and KBS

I tried to use the saga tool grid normalisation. The result is ok but the KBS has changed. Is this an error?
5
votes
1answer
572 views

How to programmatically associate a layer with a custom UI?

I know it is possible to associate a layer with a custom UI for editing feature attributes using the QGIS interface. But is this possible with Python? This link shows how to achieve the result ...
0
votes
1answer
36 views

How to access the different panels in QGIS Composer? [duplicate]

I accidentally closed the tabs in composer: Composition and Properties, I think it is called. The question: How can I open them again?
1
vote
0answers
83 views

Can I speed up very long connection times to a PostGIS DB caused by complex views?

When connecting to a PostGIS database to add a postgis layer, all table and views are scanned by Qgis in order to define the geometry type (if I understand well the query performed). My problem is ...
3
votes
2answers
144 views

GRASS v.rast.stats missing in sextante toolbox

I am new in the QGIS world and also with GRASS. I am really interested in using v.rast.stats as is doing exactly what I need. My problem is that I am not able to find it inside sextante in QGIS and I ...
0
votes
1answer
140 views

How to create a polygon feature using Python?

I'm making a plugin for Quantum GIS in python. I have a polygon layer and want to create a new feature. So far, I have this because I need a polygon geometry to add the feature: surface = ...
3
votes
1answer
75 views

Why can't I clip vectors with 2 different projections?

I am using QGIS. I am trying to clip parcel data with a stream buffer. The two have different projections. Parcels are NAD83 State plane feet and streams are NAD83 State plane meters. I keep ...
0
votes
0answers
22 views

Trouble making heat map - red square [duplicate]

I'm a beginner to QGIS and I'm having trouble making my heat map. I'm using QGIS 1.8 and Win7. I imported a CSV file with around a 1000 points (X Y coords - WGS84). When I try to make a heat map ...
0
votes
1answer
89 views

How do I add a lot of data to a shape file in QGis?

I have some nice shapefiles from Agesic in Uruguay, I need to add to them some information (not as shapefile) that I got from Dinamige to the attribute table. These institution are not the point, the ...
3
votes
2answers
307 views

How to extract all Way elements tagged as highways from OSM data using QGIS?

I want to extract/filter in all Way elements within a specific region tagged as 'highway' from an OSM file. I am currently thinking of using a Python library called osmread (by A Dezhin) that I ...
0
votes
0answers
103 views

Why am I unable to save shapefiles layers? (other layers work fine)

I'm a very new user on QGIS. I've managed to find mostly all I needed to use the software, however today I came across some problems similar to those encounted by [someone else][1]. However, when I ...
7
votes
2answers
916 views

Version editing for Postgresql 9.2.4 / postGIS 2

Background: I am "building" a GIS with PostgreSQL 9.2.4 / PostGIS 2 as the database and QGIS 1.8.0 as the geographic application. There will be multiple users accessing, editing and viewing the data ...