Tagged Questions

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

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5
votes
2answers
3k views

How to install QGIS on Centos 6?

I'm new on this; I really tried a lot before ask.. but nothing works. I did all that the qgis page says. Install ELGIS. after that i investigate and tried diferents comands.. but nothing works..the ...
6
votes
1answer
3k views

How to measure area correctly?

I have now used my entire evening, but I can't figure out how to make areal calculations (eg. in km2). I have tried the 'field calculator', I have tried the 'measure area' function on the "attributes" ...
21
votes
4answers
2k views

How to calculate terrain Curvature?

I have an elevation raster and I would like to get some basic terrain variables, such as slope, ruggedness, aspect or curvature. The problem is that I don't seem to have the possibility to calculate ...
3
votes
3answers
1k views

How to join Shapefile and Excel data without unique ID column?

I have one huge shapefile with lots of roads (polylines) along with various attributes and I have an Excel file containing some of these roads by three same attributes (road no., section no., length) ...
4
votes
1answer
95 views

Why are selected features not highlighted in OSM layers?

I am experienced with GIS, but new to QGIS and Opensource data. I recently opened an Open Street Map (osm) file in QGIS 1.8 (on Kubuntu 12.04). I found that when I selected a feature, there was no ...
2
votes
2answers
1k views

How to classify/style rasters correctly?

I am using a GeoTiff raster data and trying to classify it. I was wondering what are the techniques that I can use in QGIS to do this? The raster I have looks like but I tried the reclassify tool ...
1
vote
1answer
266 views

How to connect QGIS to an online database on Mac OS X? [closed]

I'm a real beginner/dummy when it comes to QGIS and online databases. I have tried a variety of things trying to connect to Spatialite, PostGIS and MySQL but all attempts have failed due to my lack of ...
5
votes
2answers
476 views

Setting up an online map site [duplicate]

Possible Duplicate: Steps to Start Web Mapping I have taken on setting up a database which stores information of an annual country-wide survey of alien aquatic weeds, linked to a GIS ...
1
vote
1answer
265 views

How can I import geometries from an invalid GML quickly?

I have the following gml geometry : <gml:Polygon xmlns:gml="http://www.opengis.net/gml" srsName="EPSG:2154"> <gml:exterior> <gml:LinearRing> <gml:posList ...
3
votes
2answers
740 views

How to use SAGA Kriging in Sextante for QGIS?

Hello, I tried to use SAGA (Ordinary Kriging) via SEXTANTE in QGis. The Sextante log tells me the following problem. Does anyone have a solution for my problem? By the way I'm usually a SAGA user but ...
2
votes
1answer
141 views

Qspatialite plugin problems with queries using inner join

I'm trying to create a layer in QGIS from a sqlite database using a query from 2 tables: one has spatial data and the other doesn't. When I build the query using Qspatialite using the 'Advance SQL ...
4
votes
2answers
684 views

GPS-Plugin and Garmin data

I am an avalanche specialist and I use a GPS Garmin 62 for fieldwork. I for example use waypoints to measure snow depth in avalanches for volume calculations. When I add a waypoint in the garmin ...
4
votes
2answers
327 views

How to iterate over selected layers?

In QGis by pressing shift or ctrl keys a user can select multiple layers in toc. How can a python script iterate over selected layers? I'd expect a iface.selectedLayers() but I can find only ...
6
votes
4answers
4k views

Qgis - Is there a way to split a polygon layer with a line layer?

I am drawing administrative regions that have boundaries follow streets in another layer. As these streets are pretty long with many vertices, I don't want to re-trace them. I am looking for a way to ...
4
votes
0answers
272 views

What to do about Geoserver WPS Warning “Could not get a ServiceInfo”?

This is the warning i am getting when i try to use this WPS service from QGIS, and the processing take a long time, but doesn't terminate, what might be the problem? 17 Oct 12:33:25 INFO ...
5
votes
2answers
1k views

Where can I get information on QGIS beta versions?

While searching for information on some qgis functionality on the web, i noticed several times, people using version 1.9, however this version is probably some beta (or so i thought) but i cant seem ...
0
votes
1answer
528 views

How to create a custom projection of PRS92 and UTM 51N for the Philippines? [duplicate]

Possible Duplicate: How to define new custom projections in QGIS? How do I create a customized CRS parameter in quantum GIS? I'm try to create a projection of PRS92 and UTM 51N. This ...
2
votes
1answer
281 views

Can I Dynamically Update Symbol Ranges?

Background: I'm currently trying to dynamically change the ranges for a layer with new style graduated symbology. Problem: I thought it may be as simple as updating the ranges for the existing ...
1
vote
2answers
165 views

Has Action behaviour changed between 1.7.4 and 1.8.0?

I have an Action that loads raster layers (.jp2) into the current QGIS window. This action has been working great in version 1.7.4. I have now upgraded to 1.8.0 for many reasons, but the same Action ...
0
votes
3answers
387 views

Run function if item in QComboBox is selected

I got another issue writing a plugin to convert three shape files into an .obs input file. I created a UI (Qt) with a QComboBox to select a layer (that works fine). As soon as one of the layers in the ...
1
vote
1answer
189 views

Count the number of symbols in a 'new symbology' renderer from pyqgis

Background : I create a lot of symbology using 'saturation' ramps - for want of a better term, e.g. where the hue and value of each symbol stays the same, but the saturation changes. I couldn't figure ...
3
votes
3answers
1k views

How to sum raster image values with vector overlay

I'm new to this and haven't been able to figure out how to do this on my own. Here's what I want to do ... I have two files: a raster image of land use data and a vector-based shapefile of my ...
3
votes
2answers
873 views

QGIS How to use Query Builder with a Joined table

When I join a layer with another layer all the attributes are correctly displayed in the first layer. However when I use the Query builder (Layer - Query) and then use Zoom to layer, nothing is ...
0
votes
1answer
2k views

function, return, 'instancemethod' object has no attribute '__getitem__'

I'm still trying to write a python plugin to create an input file for an urban climate model out of three shape files. Now I stumbeled into another problem, that I think is an easy one, but I just ...
7
votes
1answer
288 views

How to migrate SVG-based styles for QGIS to other computers?

I'm working on a project that has involved creating many recolourable SVG icons and bringing them into QGIS. These are then used in layer symbologies, with these subsequent layer styles exported as ...
3
votes
3answers
7k views

Editing a KML file or converting KML to Editable format with attributes

I'm using QGIS. I'm trying to either edit a .kml file someone else created in Google Earth or convert it to another editable format (like a .shp file). I've read the following threads without really ...
3
votes
2answers
173 views

Can I Combine Areas in Quantum GIS?

I am working on a provincial annual health bulletin. I have a .shp file that has GIS data about the smallest divisions called "GN Area". Two or three GN Areas form one MOH area. I want to get the ...
1
vote
1answer
192 views

Analyse spatial data and extract results in tabular form in QGIS

I'm sorry if this question is badly framed, I only started with GIS and QGIS 2 days ago so I don't know any terminology yet - I'll try to explain as best I can. I have 2 layers in QGIS (1.8, on ...
4
votes
1answer
2k views

Installing QGIS on Mac OS 10.7. “The GDAL framework is required.”, and yet I have it

what did I miss? I'm trying to install QGIS on my MacBook (Mac OS 10.7). I'm following these instructions: https://sites.google.com/site/eospansite/qgis-installation/installing-qgis-1-6-on-macosx It ...
2
votes
1answer
823 views

How to fix The procedure entry point squlites3_open_v2 could not be located in the dynamic link library squlite3.dll? [duplicate]

Possible Duplicate: How to fix QGIS error “Entry Point could not be located”? I downloaded QGIS to my laptop (Window 7 64b) yesterday but when I click on the desktop logo I get the ...
1
vote
0answers
444 views

How to reproject a raster in QGIS? [closed]

I wanted to reproject raster file from UTM to decimal degree in QGIS version 1.7.1 or 1.8.0.. I could reproject one raster file before in QGIS Version 1.8.0. I have tried again, but now we cannot ...
10
votes
2answers
8k views

How to reproject a vector layer in QGIS?

I have some shape file which is in UTM. I wanted them to convert to Decimal Degrees in QGIS. Thanks.
2
votes
1answer
271 views

Hyperlinking to PostGIS Layers and Zip files with QGIS Actions

I previously asked a question about hyperlinking data in QGIS that gets loaded into QGIS (see post: Hyperlinking in QGIS - Add Data to current window). A user provided me with the code, which works ...
2
votes
0answers
58 views

QGis, add dialog and classes to plugin

what are the steps to add files that represent a uidialog(draw with QTDesigner), and add the necessary python class files, using the default makefile provided with qgis plugin builder? thanks,
-1
votes
1answer
232 views

Imported points from csv file (latitude, latitude) don't show up in a post code shape file

I can produce a point vector layer by importing latitude and longitude info from a csv file in a new project. After saving this file as an ESRI shape file I can import it in a Postal Code shape file. ...
2
votes
1answer
198 views

Is it possible to rectify an aerial photo with known control points in 3d, in QGIS?

Bonjour, Peut-on avec Quantum GIS redresser une photo aérienne avec des points caractéristiques connus en 3D (XYZ) ? -- Translation: Hello, Is it possible to rectify an aerial photo with known ...
3
votes
1answer
513 views

Can I move points by editing x/y in attribute table?

Im new to QGIS and I just cannot figure out how to do this one hopefully simple thing: I have a bunch of points in shapefile and i need to move some of them around by hand / coordinates. I've ...
3
votes
1answer
674 views

Is it possible to change the plugin folder location?

Sorry for the vague header but i found no better one. This is the situation: I am teaching a GIS course in a local collage using QGIS (qgis4w). The way our lab pc's work is that they delete all added ...
4
votes
1answer
3k views

How do I edit shape file attribute tables so they all have the same information?

I am trying to merge several pipeline shapefiles using GEOMERGE but it cannot complete the function because they have different column definitions. So I need to edit the attribute tables so that ...
2
votes
1answer
585 views

When I finish drawing a polygon, it disappears again (although appearing in my attribute table)

I'm working with Quantum GIS at this moment. And as the title says, when I finish drawing a polygon, it disappears again. The new object does appear in my attribute table and in the legend/'filling of ...
1
vote
5answers
392 views

Error when starting up Postgis Manager plugin in Quantum GIS

I receive an python error when starting the postgis manager pluging in QGIS. This problem started when moving from QGIS 1.7.0 to QGIS 1.8.0 Lisboa. I reinstalled everything but that didin't fixed ...
0
votes
1answer
68 views

How to view the class files of QuantumGIS for further development?

I have been searching class files of QGIS for a while for customisation and edit it for a project..But I am unable to get or download the files...can anybody give some references if we can really view ...
11
votes
4answers
9k views

Feature comparison between QGIS and ArcGIS for Desktop [closed]

I am learning to use QGIS and ArcGIS for Desktop but I cannot find the differences between them. What are the differences between the capabilities of QGIS and ArcGIS for Desktop?
1
vote
0answers
185 views

How to view error feedback in qgis when testing connection to postgres database?

Using qgis 1.8 on Ubuntu 10.04 with Postgres 8.4.13 I am creating a new (and my first) Postgresql connection in qgis. I can connect to the user and the db using the pgsql client. ...
3
votes
1answer
605 views

Get extents of vector shape features in python

i am just wondering if it is possible to iterate through vector features and return the extent per feature without clipping the vector shape? The code looks like this and comes from the ...
1
vote
1answer
168 views

Unable to load the GADM data in QGIS

I have downloaded the shapefile of Mexico's Admin Boundaries from the GADM site but I am not able to load it in QGIS. It keeps giving me the following error, ...
7
votes
4answers
5k views

Using android phone to plot GPS points?

I was wondering if I could use my android phone (HTC Wildfire) to plot gps points and export these into GIS software (I have QGIS and MapInfo). Thanks, Alan
0
votes
0answers
68 views

QGIS anno labels

Is there a way to copy and paste Anno Labels in QGIS? I have a layer that contains Parking Restriction information e.g. No Waiting or Limited Waiting 1 hour Mon - Fri 9am - 10pm etc. There are lots ...
1
vote
0answers
71 views

QGIS Loaded Plugin Access

Fellow Users, Can you plz tell me how I can programmatically (or from the console) access the loaded plugin list? I tried: QgsProviderRegistry.pluginList() but got: TypeError: ...
10
votes
1answer
361 views

Is it possible to edit layers from a FGDB - File Geodatabse in QGIS?

I think I've found the answer (you can't edit FGDB's) but there seem to be few reports around that it is possible to edit FGDB files in QGIS. Can anyone advise if it's possible to setup QGIS ...