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

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3k views

Is it possible to export GeoPDF from QGIS?

Is there any plugin for QGIS which would help me in exporting the map document as a GeoPDF ?
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5answers
7k views

How to perform Raster Reclassification in QGIS?

Is there a way to do reclassify a raster image to Qgis? In Arcgis you can do that in Spatial analyst Tools→Reclass→Reclassify Any ideas?
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3answers
3k views

Are there open-source alternatives to ArcGIS online that can be hosted on my own server?

I know this might be too broad topic. But I am looking for web-GIS portal similar to ArcGIS online that is self-installable (configurable) to be hosted in my private server. The main features should ...
11
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2answers
575 views

Is there an automatic function in QGIS to package all shapefiles in a project for transferability?

In my project, I use a lot of geodata from different directories. Now I want to give the QGIS project to a colleague (eg on a CD). Is it possible to copy the shapes from different directories ...
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1answer
6k views

How do I calculate the latitude and longitude of points using QGIS?

I'm trying to figure out how to calculate the lat/long of points using the QGIS field calculator. Is there an easy way to do this? I saw a previous related question, but it deals with a more advanced ...
11
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1answer
2k views

How do I build a custom form for entering attributes in QGIS

I've done this many times in ArcGIS and ArcPad but I don't even know where to start building a custom form for data entry in QGIS. I would like to do this for field operations--QGIS would make a good ...
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3answers
257 views

What is the most appropriate journal for publishing a paper about data collection with QGIS and mobile equipment?

I am a QGIS user, and a few months ago, we used QGIS on a PC Tablet to collect data on nesting birds on a cliff directly on the field. The principle is to have QGIS installed on a PC-Tablet with an ...
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2answers
2k views

How to concatenate labels in QGIS?

I'm using QGIS 1.8 on windows XP machine and I try to do a concatenation of several fields to label the names of my local roads in the attribute table, but I can not find the correct syntax. The first ...
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3answers
14k views

How to convert a vector layer to raster?

In qgis in the raster menu there is an item "convert vector to raster". This behaves strangely - I do not understand how it is supposed to work. I can select a vector file, an attribute and an ...
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2answers
513 views

How to clean such a bad shapefile for routing ?

I am trying to clean a shapefile to make it usable for routing with pgrouting, postgis, postgresql. Here an intersection, it seems to be connected but when we zoom …. It is not: Same here : ...
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4answers
10k 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?
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2answers
5k views

How to use label classes, expressions, and annotations?

I've always found that when it comes to python, vector analysis, QGIS gives ArcGIS a run for its money, hell some of the qgis plugins exceed ArcGIS's performance by a few hours; however, I always have ...
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2answers
701 views

Moving points onto lines (~neighborhood)

I do have two vector layer, of which one is a point layer based on "events" by remote sensing and the second one is a line layer from local research. In my case these are earthquakes and tectonic ...
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2answers
986 views

polishing qgis map for publication using inkscape

I have a problem modifying the map I created in QGIS. I need to add some text on the map and axis labels. Apparently, labels cannot be rotated in qgis, so this I need to do in inkscape or in a related ...
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3answers
3k views

Is there a way to use “Select by Attribute” in QGIS using a python command?

is there a way to use the function "Select by Attribute" in QGIS using a python command? In my plugin the user should enter a value via a GUI and this value should be used in a function which selects ...
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2answers
7k views

How to run a simple python script for QGIS from outside (e.g. Sublime Text)?

I would like to run a few small and simple python scripts for QGIS (Mac) from "outside" of QGIS. With outside I mean in this context, either the normal os command line (terminal.app) or even better, ...
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3answers
340 views

How to improve drawn shapes in Quantum-GIS?

I have a polygon-shape in qgis-1.7.0 and want to fix overlays and gaps between the edges of adjacent polygons. See image below. Is there any automated way to do this in quantum-gis? Or any other ...
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5answers
4k views

How can I map a matrix of origins and destinations in QGIS?

I have a central point on a map, and I have other points in a separate layer (the location of a venue, and the origin cities of the venue visitors). Is there a plugin which would generate output ...
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1answer
132 views

Identify points in a shapefile that have no other point within x km with QGIS

This is probably a naive question but I am struggling as a new user to QGIS. I have a very large shapefile (275,000 points, but can break this into about 10 subregions if necessary for faster ...
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1answer
6k views

Merging adjacent polygons in shapefile that has been split at tile boundaries?

I'm currently using building data from the Ordnance Survey Vectormap District and I've noticed that a lot of building polygons are split in 2 because of the way the OS split up the shapefile. This is ...
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1answer
539 views

QGis raster terrain analysis - The curvature filter puzzles me

I am a french Master student at university Grenoble INP, and during my master project I have worked on DEM (raster) terrain analysis. Thus, I have read the source code of several QGis-1.7.4 raster ...
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1answer
735 views

Method to shade or overlay a raster map to reflect time of day and ambient light

I have a daytime raster of my study area. I have 20+ counters in the study area that count "stuff" with a timestamp. Using PyEphem I determined the type of ambient light for each collected data ...
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1answer
577 views

Nearest Neighbor Grouped Selection in QGIS

OK - so I have an interesting problem I am trying to solve. I have a list containing over 100,000 points in lat/long format which I have imported into qgis. Now, what I am trying to do here is group ...
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3answers
594 views

Contours: Interrupt contour lines beneath a elevation number

Is there a way to interrupt a contour line beneath a elevation number? Thanks!
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1answer
385 views

How to associate polygons with the nearest point on a point layer? (Or … how do I assign a postal area to a salesman?)

I have a polygon layer of postal code areas and I want to use them to create sales territories based on where our sales people are based. So I assume that I need to work out for each of the polygons ...
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4answers
2k views

How to connect lines in a network?

I have a shapefile of lines and another of polygons. When two or more lines intersect a polygon they should be connected (snapped), but sometimes during manual digitization this doesn't occur. I need ...
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1answer
777 views

Snap line layer to network in QGIS or PostGIS

I have GPS data I've taken of bus routes, and now I'd like to snap it to my road network. Both layers are line layers in a PostGIS DB. I'd like to use either QGIS or PostGIS, but if I have to go with ...
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2answers
292 views

How to sort by multiple fields at the same time?

Is it possible to sort multiple fields at the same time in QGIS? For example, I'd like to sort a table by state name, and then within each state, sort by county name. This would be the same as the ...
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1answer
435 views

How to create text labels with background boxes?

I'm trying to create some custom labels for point features in a QGIS point vector layer, and I want to write a python plugin to do it. We need our labels to be presented with color tinted rectangles ...
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5answers
11k views

Changing CSV layer attribute value from text to number in QGIS?

I read in a CSV file for linking to a .shp file. All the variables that are just numbers came in as text. How do I change the text variables to numeric in QGIS?
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5answers
577 views

Database versus Files for Solo Developer

I'm just getting started in GIS and am interested in using it to create maps of mountain biking trails in my area and nearby. I've been learning QGIS and have made enough progress to generate a decent ...
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2answers
9k 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.
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4answers
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How to export shape file to SpatiaLite

I have a shapefile with one layer. I can open it with QGis. Now I want to convert this shapefile or layer to Spatialite database. How can I do it? Is it possible to do with QGis?
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2answers
5k views

How to rename attributes/fields in a shapefile attribute table?

I would like to rename some fields in my attribute table: Like rename XRF_N3in something else. It seems quite a easy issue but I don't find any information about how can I do that... I've QGIS 1.8 ...
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6answers
1k views

How do I make a heat or Choropleth map that uses polygons in QGis?

I've been playing around with the heatmap plugin for QGIS and I am wondering if it is possible to make heatmap with using a similar plugin/tool that uses polygons as well as points? I would like to ...
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5answers
1k views

Multicriteria Analysis : how to?

I have to do a multi-criteria analysis to answer the question : "which is the best lot to develop". A few of the criterias are : distance of the nearest bus stop (point layer with bus stops) ...
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2answers
11k views

How can I join several raster files using QGIS?

I'm new to QGIS. How can I combine multiple raster layers into one layer? The raster images are of different areas with very little overlap. The goal is to bring numerous town plats into one project. ...
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4answers
2k views

How to buffer in pyQGIS?

I'm looking for some examples to do simple python scripts in QGIS. How would I do a buffer analysis on a dataset? I can't seem to find much in the manual and QGIS python that quite matches the Esri ...
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2answers
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Running QGis from flash drive

How can I setup a portable QGis to run from a flash drive / USB-Stick? In the userguide for QGis 1.7 Wroclaw there is only mentioned the option of "--configpath". But to me it is not clear how to deal ...
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2answers
452 views

Can I add an ArcToolbox tool to QGIS?

I have been using a publicly available tool in ArcGIS called SPreAD-GIS. It is a series of python scripts that are "implemented as an ArcGIS toolbox" (with tbx file). I am new to QGIS. Is there a ...
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3answers
9k views

How to import coordinate data from excel into QGIS?

I have an excel file containing data collected over many years as latitude and longitude coordinates for archaeological sites - how can I import it into QGIS as a new layer?
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1answer
3k views

How to display geoJSON from an URL in a layer?

I am looking for some type of plugin or code which would allow me to add a geojson URL, define the areas to input the lat/long variables from the visible Qgis canvas map and call/render the results ...
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4answers
4k views

How to create equidistant points in QGIS?

I am trying to create points (new layer) at specific distance along the road (existing layer) in QGIS. This gives solution for ArcGIS. How to achieve this in QGIS? This one explains how to create ...
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3answers
6k views

How to determine the centroid of polygons?

I have a polygon vector and I want to quickly attain the centroid of this polygon for insertion in a text document. I am working with QGIS. I searched through other questions and although some are ...
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2answers
4k views

How to check Topology in QGIS?

I have two Shapefiles with Polygons ( City and Forerst) Is there a Plugin who is able check the topology (QGIS)? Like "Knots do not overlap" or something like that? I dont want that they overlap. ...
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5answers
2k views

How to identify duplicate attributes in a field?

I have a point shapefile with thousand of points. It has an ID code field that supposed to be unique. Every now and then the data entry clerk wrongly type the id creating duplicates.Right now I'm ...
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1answer
2k views

How to create desire lines in QGIS?

How can I show the flow coming from an Origin-Destination matrix as desire lines? I need a result like the one in the picture below. I need to scale them proportionally to its value (coming from a ...
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3answers
301 views

How can I parallelise embarrassingly parallel GIS operations in QGIS python?

A common requirement in GIS is to apply a processing tool to a number of files or apply a process for a number of features in one file to another file. Much of these operations are embarrassingly ...
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1answer
545 views

Is there a way to add system date in print composer?

Is there a way in the Print Composer of QGIS to create a label that will automatically update the date (systems date) instead of having a label that you have to manually have to update?
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2answers
11k views

How to Add OSM Layer to QGIS

How can i add OSM layer in QGIS? The help says there is an OSM plugin i can use. But i don't see it the list of plugins. Or maybe there is a WMS URL for OSM i can use? QGIS version ...