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

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8
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2answers
4k views

Implementing Spatial Autocorrelation using QGIS or PostgreSQL or any other 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 ...
0
votes
0answers
21 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 ...
2
votes
0answers
309 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 ...
1
vote
0answers
30 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
votes
1answer
1k 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 ...
1
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0answers
148 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 ...
0
votes
2answers
422 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 ...
3
votes
3answers
841 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. ...
0
votes
0answers
60 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 ...
1
vote
1answer
151 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 ...
0
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0answers
33 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.
1
vote
2answers
2k 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 ...
1
vote
1answer
433 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 ...
1
vote
2answers
253 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 ...
0
votes
1answer
400 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 ...
1
vote
2answers
469 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 ...
5
votes
1answer
719 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 ...
1
vote
2answers
2k views

How to restore original Settings Menu in QGIS (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 ...
0
votes
2answers
2k 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 ...
2
votes
0answers
223 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 ...
0
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0answers
64 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 ...
7
votes
2answers
2k 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 ...
2
votes
1answer
508 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 ...
6
votes
1answer
2k 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()) ...
1
vote
2answers
288 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 ...
1
vote
1answer
584 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, ...
5
votes
2answers
4k 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
votes
1answer
1k 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
vote
1answer
384 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
votes
1answer
2k 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 ...
1
vote
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 ...
24
votes
1answer
3k 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
votes
1answer
135 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 ...
4
votes
1answer
610 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. ...
2
votes
1answer
866 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 ...
3
votes
1answer
186 views

Is it possible to use different symbols instead of colours in one shapefile in QGIS?

I want to show 50 bird species on a map and give each species a different symbol (with a different colour) so they can be visually distinguished in the map. Is this possible?
4
votes
1answer
859 views

How to repair and clean contours from high data resolution (lidar)?

I'm unsuccessfully trying to make a bathymetric map with contours extracted from Lidar data at 1 m resolution. The extracted contours have a lot of artifacts like dangles and islands. First I used ...
2
votes
1answer
644 views

Integrate QGIS into Hadoop cloud is it possible?

It might be very basic question. Can I integrate QGIS +Hadoop cloud? Currently I am going through similar question and few research articles & researching on my side. In upcoming ArcGIS 10.2 ...
1
vote
0answers
64 views

QGIS automatically inserts segments when editing polygon nodes

I have created a shapefile with multiple polygons. When I attempt to move one of the veritices with the node tool new sements automatically appear that cross the polygon and even cross the opposite ...
1
vote
0answers
636 views

How to debug QGIS Server WMS “Download of capabilities failed”?

Currently I am using a QGIS server with a linux Centos system. I am attempting the create a WMS in QGIS and upload it to my website. I have followed the instructions in the "Quantium GIS User Guide: ...
2
votes
0answers
36 views

Why are there changes in location when printing inserted points? [duplicate]

Añadí una capa de texto delimitado por comas y luego agregue una imagen satelital de google earth. Realizo un diseño de impresión y al imprimir cambia la ubicación de los puntos en varios metros. Cual ...
1
vote
1answer
122 views

Digitized vectors don't match while zooming [duplicate]

I'm trying to digitize in QGIS with Google Maps as the background. Digitizing with constant zoom works fine. But if the zoom is changed, the digitized vectors don't match the Google Maps background ...
5
votes
1answer
149 views

Is there an Attribute Table Feature limit?

I am copying a table with 11,000+ features but only about 700 show up on the QGIS attribute table. Is there a limit? how can I avoid this problem? Thank You in advance!
0
votes
2answers
990 views

Select / Deselect and Identify Features in QGIS

Sorry if this is all a bit 101, but I'm new to QGIS. I basically have a large Arc project that I can access in QGIS for reference, so will only really be using it to identify features. For example to ...
4
votes
1answer
350 views

How to print selected features in QGIS?

I have a detailed map in qgis (vector, .shp) and I would like to split the map in four parts based on attributes to print each part of the map separately. Unfortunately, I didn't figure out how to do ...
3
votes
1answer
435 views

Masking/removing polygons from shapefile

I have a shapefile containing the road traffic noise of a city. The shapefile has 5 columns, where 'noise_in' (noise interval) ranging from 1-5 is included. I want to remove/mask the road noise from ...
1
vote
1answer
127 views

Adding points with defined intervals in QGIS [duplicate]

I'm trying to make a grid with points of defined intervals (e.g. 5 m). How can I achieve this with QGIS?
1
vote
1answer
273 views

What are use cases of Esri's CityEngine?

I would like to know the use cases of Esri's CityEngine, and what distinguish this tool from the other standard GIS like ArcMap and QGIS? and in which fields could be used ?
1
vote
1answer
145 views

How to combine use gradient symbols for layer properties excluding 0?

I want to visualize my data by using graduated symbols. Now, there are some objects with value "0", they should not be printed on the map (which I solved by using rule-based symbols). But, anyway, "0" ...
2
votes
0answers
401 views

problems uploading data onto qgis cloud

I am using QGIS 1.8.0 on a windows 7 machine. Trying to upload a project onto QGIS Cloud. I have 2 issues. Firstly when i go to publish a map it directs me to upload the data. As i am using a free ...