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

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132 views

QGIS GDAL polygonize - how to set scale

I've got some old contour plots, paper copy only, that I'd like to be able to put into QGIS. I get as far as a successful polygonize into shp and it looks fine, but the scale is wrong. How might I ...
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2answers
219 views

Hypothetical Cost Saving Question: Proprietary v Open Source

I am writing a paper for my GIS MSc and trying to justify a move for the EPA from proprietary GIS software to open source (QGIS). Can anyone hazard an educated guess as to how much ArcGIS would cost ...
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1answer
260 views

AttributeError: HelloWorld instance has no attribute 'connect'

Here's the code: import sys,os import win32api from PyQt4.QtCore import * from PyQt4.QtGui import * from qgis.core import * import ctypes from PyQt4 import uic class HelloWorld: def ...
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0answers
202 views

ArcGIS Raster Calculator VS QGIS Raster Calculator [closed]

Are there any major differences between ArcGIS Raster Calculator and QGIS Raster Calculator?
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2answers
152 views

How can i mark movement route to the map with QGIS?

I am beginner with QGIS and i am having problem with marking movement route to the map. So i would like to ask how can i mark movement route to the map with QGIS. I have a list of cities and i have to ...
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1answer
71 views

Give Properties to a shapefile to be used by another person [duplicate]

I have bedrock geoology data. I want to classify the data so it appears with the same propeerties as it does on the suppliers website. Is there a way i can attribute a property to a layer (in this ...
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2answers
211 views

How to select polygons in polygon and export to CSV?

I have two polygon layrers, each layer a table in PostgreSQL: One layer with polygons areas in a city. Another layer with buildings (polygons) that are within areas. How can I to do to know what ...
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2answers
224 views

Identify points near roadside in QGIS

How do I create an attribute list from points that run along roads in a shape file containing road data? The points don't intersect the road centre lines and are not consistent in their distance from ...
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1answer
206 views

Merge attribute data using spatial query in QGIS

I have 2 vector layers that I wish to correlate attributes - a shape file containing boundary polygons and a shape file containing point locations. I'm using the vector>spatial query tool to generate ...
3
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1answer
129 views

Filter contour lines in QGIS

I have a shapefile of contour lines, with an ALTITUDE attribute with the height ASL in metres. The source data is in 0.5m intervals, but I'd like to filter it down so I get contour lines at (for eg.) ...
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1answer
613 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 ...
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0answers
104 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 ...
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1answer
491 views

How to set Marker Line symbol for QgsVectorLayer by using Python?

QgsVectorLayer Right click->Properties->Style->Single symbol->click on simple line in tree node ->symbol layer type -> Marker line Kindly help me to set marker line symbol programmatically by using ...
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83 views

Is there free desktop WFS client with BBOX support?

To troubleshoot WFS server (geoserver) with big dataset (global OSM btw) I have tried number of free GIS desktops which work on Mac: QGIS (1.8, 1.9dev), uDig, gvSIG - none of them seems to support WFS ...
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1answer
189 views

“Request contains a format not offered by the server.” Error when using CRS transformation with WMS in QGIS

When I try to load a WMS layer which has a WSG84 as a default projection and use a CRS transformation on it, it gives this error message: Request contains a format not offered by the server. The WMS ...
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2answers
1k 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 ...
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20 views

De facto QGIS projection for EPSG4326 / 'unprojected' reference systems? [duplicate]

This is my understanding of projections/datums: To get a map of the earth on a plane you need to project the 3 dimensional earth by 'wrapping' a plane around it in the way that suits you (according ...
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0answers
229 views

How to create stacked bar/column charts in QGIS?

I know that conventional bar charts (with the bars adjacent to each other) based on feature attributes can be plotted in QGIS. But can you please tell me if there's any way to plot the bars in the ...
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0answers
25 views

Displaying PDF files associated to feature objects location. [duplicate]

Are there any other methods allowing user to display PDF files associated to points feature object other than using Actions function available to QGIS Layer Properties? I have more than one thousand ...
2
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1answer
474 views

How to create a date field in QGIS shapefile

When I create a new shapefile in QGIS, I'm presented with the "New Vector Layer" window, where I specify the Shapefile type (Point/Line/Polygon) and am then able to create attribute fields. I'm only ...
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0answers
111 views

Why doesn't dissolve finish? It just stops without error message

I have a shapfile of the whole UK that contained Postcode area, district, and full postcode. I was going to try and dissolve the regions into seperate business areas by joining a lookup table that ...
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2answers
208 views

How to make line with arrow head in QgsVectorLayer using python?

I need to draw line with arrow head or after drawn the line i need to make it as arrow head line by using python. or can we set any arrow head symbol for line features by using python? Kindly help me ...
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3answers
409 views

How to clean layers from non topological databases?

I'm doing my internship in a consulting office which is switching from MapInfo to QGIS/GRASS 1.8.0. I posted here a few days ago about the way to clean a polyline from a Lidar data with v.clean. ...
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0answers
53 views

Problem with Georeferencer not scaling TIFcorrectly

I am trying to use QGIS and the Georeferencer to digitize paper maps but I am unable to get the raster to rotate afte I pick my control points. Below is a brief outline of the steps I used to ...
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1answer
90 views

I don't seem to be able to save Layer Styles in QGIS

I have created and saved layer styles, not recently I admit but have done in the past. For some reason or other I just don't seem to be able to save any new ones in QGIS. No file is created. It does ...
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31 views

QGIS: Unable to project raster layers correctly on a Toshiba Tecra 64# Win7

I know how to project a raster, I can do it on other machines. On this particular machine the raster loads but are no where near the correct position as if the datum is on another planet.
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2answers
905 views

How to resolve missing Python module (importlib) for GRASS/Sextante?

I have installed the nightly build of QGIS 1.9 from Larry's Dakota Cartography site, and have downloaded the latest Frameworks from William's Kyng Chaos site. However, I am unable to install the ...
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1answer
201 views

How to prevent Qgis clipper to clamp nodata values?

I'm trying to crop some old georeferenced cartography in order to have a continuous map (every map has its blank borders that overlaps). Usign raster->extract->clipper and setting no value to -32768 ...
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1answer
101 views

Worsened image quality and false colours after georeferencing

When I georeference a map of vegetation types (about 20 colours, each representing a certain vegetation) the quality of the georeferenced map is really bad and some colours have changed (e.g. black ...
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1answer
208 views

QuantumGIS EPSG:3857 doesn't match with leaflet

Leaflet documentation said that they has EPSG:3857 as default projection. Using QGIS with open layer plugin, I point to a location to find it's coordinate. I used EPSG:3857 in QGIS as well. The ...
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2answers
206 views

define a datum and meridian in a CRS in QGIS

I have a shapefile defined by the source as: "The layer is in geographical (lat-long) coordinates (GCS_Clarke_1866; Datum: D_Clarke_1866; Prime Meridian: 0)." opening the shapefile in QGIS 1.8 the ...
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1answer
359 views

How to access the road graph plugin in python?

I am developing a few scripts in Python for QGIS 1.8 to automate some geo-tasks and one of them would be to calculate the shortest distance from a hospital to each building in a town. I would like to ...
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2answers
697 views

How to restore the original Settings Menu in QGIS 1.8 (customization)?

Making some tests in Windows XP for customizing a user interface in QGIS 1.8 (see http://www.duif.net/qgis/doc/output/html/en/docs/user_manual/introduction/qgis_configuration.html#customization), I ...
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1answer
691 views

Topographic Wetness Index

Is there any option to SAGA to calculate the Topographic Wetness Index ? I have a big area and I tried many times with SAGA, the last time I thought the results was ok (before SAGA would crash or give ...
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0answers
148 views

qgis python app how to add edit feature button?

I'd like to develop a QGIS Python app for plotting points and editing the attributes. I've started with the tutorials here: http://blog.qgis.org/?q=node/59 and read the cookbook ...
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49 views

QGIS Identify tool on vector Crash

I have built QGIS (1.7.4) on Mingw successfully and everythings seems to be alright. My own plugins are also identified and working fine. There is a crash when using identify tool/ attribute table ...
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2answers
527 views

Is the QGIS cache directory automatically created?

This question is directly a result of a question posted earlier about the units of cache size: QGIS - what is cache size measured in I went to the Options menu in QGIS, to the Network tab. Here is ...
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1answer
154 views

What is cache size measured in?

Can anyone tell me what the units are for the Cache Size setting in QGIS please? Is it bytes, KB, Mb, MB? When I look in the directory specified by the path (/Users/.../.qgis/cache/) the cache ...
5
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1answer
653 views

How to create a dropdown menu in QGIS Toolbar with Python

I Have a set of some QAction in my QGIS-Plugin and they are created and added to the toolbar like this icon = QIcon(":/action1.png") self.action1 = QAction(icon, u"Action 1", self.iface.mainWindow()) ...
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2answers
199 views

QGIS on Mac WKT import problem

QGIS 1.8.0 Mac OSX 10.6.8 These problems seem to be specific to Mac, as two Windows users don't have the problem. Import a file as a vector: TEST.CSV id;wkt 1;"POLYGON((10 10,20 20,20 30,20 ...
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1answer
340 views

Flow mapping visualization using a road layer

I am trying to illustrate travel using a flow map on a road layer. My data is: city of origin destination number of travelers I would like to use a polygon city layer (or point) and a road layer, ...
3
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2answers
2k views

Is there a zonal statistics tool to calculate median and mode raster values for each polygon?

I'd like to calculate zonal statistics for a raster where the zones are defined by polygons in a vector layer within QGIS. Specifically I'm interested in calculating the median and mode raster values ...
3
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1answer
448 views

How to merge Waypoints from many GPX files?

I have a large number of Waypoint-layers (gpx) and would like to merge them. Is there a way to do so using QGIS? Thank you!
1
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1answer
183 views

open QGIS project with parameters

I am looking at a piece of work to deploy QGIS as the standard within an organisation. There is an existing piece of software that I need to link to QGIS so that when a button is pressed within the ...
3
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1answer
699 views

How to find the nearest line to a point in QGIS? [duplicate]

My question is that given a point and few lines, how should I go about finding the nearest line to the point? I am aware of How to I find the nearest line to a point?, but that isin ArcGIS and ...
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0answers
20 views

QGIS Map Composer, right hand pane has gone! [duplicate]

in the QGIS map composer, I accidentally closed the right hand pane, the pane that includes the command history, item properties, etc. Now I can't get them back. There are no icons to click to get ...
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1answer
963 views

How to draw perpendicular lines in QGIS?

I have a situation like this: What I need to do is to connect each point to every line that is at most, let's say 200 m, away from the point. In other words, I need to draw a perpendicular line ...
2
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1answer
91 views

How to have QGIS show the number of points that overlay the raster polygon?

I have a number of single-value raster layers defining a area mask and a point layer pulled from PostGIS. Is there a way to have Quantum GIS show me the number of points that overlay the raster ...
3
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1answer
219 views

How to import or incorporate formated Excel tab into QGIS print composer

I would like to know if there's a way to import formated Excel Tab into QGIS print composer. Below is an attachment of formatted Excel tab example I has been asked to display on qgis map composer. ...
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1answer
228 views

How to “Merge Selected Features” with python?

I have been looking for the answer to this question for some time now, but can't seem to find it! My problem is straight forward: I have one layer It contains lots of features (only polygons), say ...