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

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14
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3answers
361 views

Is it possible to use symbols instead of colours to visualise raster cell values?

I have a raster image (GeoTIFF) with integer values. I know how to visualise raster values in QGIS using colormaps or similar, but I would like to assign symbols to each colour value instead - just ...
14
votes
2answers
4k views

What's the relation between QGIS and GRASS?

I have been working with GIS and remote sensing in an university and professional environment some ten years ago (ArcInfo etc), so I have some experience even though somewhat outdated Right now I am ...
14
votes
5answers
14k views

How do I create point features with exact coordinates?

How do I create point features with exact (manually entered) coordinates in QGIS? I get precise GPS coordinates from a survey team which I need to add to a point layer. What I want: -Add point, type ...
14
votes
6answers
4k views

What's the best way to produce a density map from weighted points in QGIS?

I'd really like to repeat the functionality of the ArcGIS Kernel Density tool - how could I do that? I would like to limit answers to easy-to-install free-and-open-source software – i.e. QGIS ...
14
votes
5answers
1k views

Find pseudo nodes in free GIS software

Software gvSIG OA Digital Edition 2010 have tools topology for finding pseudo nodes in linear geometry. I set cluster tolerance 0.00002 and maximum number of errors -10000 for 20000 link count linear ...
14
votes
6answers
815 views

Can I transfer custom QGIS settings from one computer to another?

Can I export custom general settings from my QGIS installation to a file so that I can transfer the settings to QGIS on a different computer? Does QGIS have them already saved to a file located ...
14
votes
2answers
1k views

Creating Thiessen (Voronoi) polygons using lines (rather than points) as the input features?

I have a set of line features inside a particular polygonal boundary. For each line, I'd like to generate a polygon inside which every possible point is closer to the given line than to any other line ...
14
votes
3answers
1k views

Rubber sheeting in GRASS or QGIS

We are in the process of getting our property boundaries corrected and a side effect of this is that we need to move any assets that have been drawn relative to the property boundaries, so they are ...
14
votes
1answer
1k views

Voronoi polygons that run out to infinity

I have been working on implementing the voronoi.py script (Bill Simon's translation of Steve Fortune's code). According to the QGIS link it is basically the same code that I am working with, but the ...
14
votes
1answer
2k views

Can QGIS preserve layers when exporting to PDF?

In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself). When I export from QGIS to PDF, I don't ...
14
votes
2answers
1k views

How can I merge/collapse nearby and parallel road lines (eg. a dual-carriageway) into one single line?

I have a shapefile from OSM which contains all the roads within a city. Larger roads (like dual-carriageways) seem to have 2 parallel lines. I'd like to collapse / combine those into 1 line so I can ...
14
votes
1answer
470 views

Hand drawn sketchy symbology styles for GIS software

Often times in planning projects, a hand drawn, sketchy look is desirable in order to convey the preliminary nature of a project. Is anyone aware of any utilities/plugins for desktop GIS software ...
14
votes
2answers
1k views

How to generalize a polygon file and maintain topology in QGIS?

my problem: I have a polygon-file in shape-format, which I need to generalize. How can "split" the polygons into lines, generalize and than "rebuild" the polygons, so that I can ensure, that there are ...
14
votes
1answer
723 views

Monte Carlo simulation using QGIS and pgRouting on optimal sidewalk construction

I am new to spatial analysis and would appreciate some general direction on a project I am attempting, outlined below (I am starting from scratch). GOAL: To find the best locations to install 2000 ...
14
votes
0answers
326 views

How to query OSM for all beaches facing west? - QGIS preferred

I want to identify all beaches on this planet (or a given subset of it) that are facing westwards (+/- 20-30 degrees). My idea is to use OSM as the data source. Extracting all polygons that have the ...
14
votes
1answer
1k views

How to load Ordnance Survey OpenSpace in QGIS?

The version of gvSIG that I have on my Android tablet will load OS OpenSpace layers and I wonder whether or not it would be possible for QGIS desktop to do the same? And if so, how? I have my own ...
13
votes
6answers
864 views

Which topics are essential for a crash course in QGIS?

What topics do you think are essential in a 25-hour "crash course" introduction for Quantum GIS? What topics do you think are nice extras to be included in such a course? Target audience: Zero or ...
13
votes
5answers
1k views

Where to start learning how to make maps with QGIS?

I have no skills in GIS, "map-making," or any other map program. Been a county planner for 25 yrs, where there was always a "drafting" staff. I'm in another agency now and need to be able to produce ...
13
votes
3answers
824 views

Why Do Colors Look Darker When Printed on Paper?

I made a map with a terrain-colored relief-shading in the background. I then exported them as PDF from Print Composer in QGIS. But when I print the PDF onto paper: the shaded-relief color in the ...
13
votes
4answers
1k views

Are there tools to directly import QGIS projects into Tilemill?

Now that there is a tool to convert an MXD to Tilemill, one must then wonder if the ability to open QGIS documents in Tilemill will ever exist.
13
votes
3answers
5k views

Is there a way to render lines with a smooth (bezier) curves in QGIS?

I am moving from creating maps with Illustrator to making them with QGIS and actual data. One of the things I haven't been able to re-create in QGIS are the smooth curved lines I can get in ...
13
votes
2answers
802 views

Polygon gradient fills / tint bands in QGIS

Is it possible to use a gradient fill on a polygon in QGIS? I would like to have my polygons with a colour at the edges, fading to clear/white as it moves away from the edge. The majority of the ...
13
votes
3answers
3k views

Idiots guide to expressions for QGIS

I have no formal training in GIS and have learned on the fly with ArcGIS 9.3 at work and have been dabbling with QGIS on my own time for my business. Is there any resource recommendations ingeneral ...
13
votes
1answer
2k views

How to have a drop down list for feature editing (attributes) in Quantum GIS?

I'm editing a lot of polygons of a shapefile in QGIS and i need to classify them, so i have to write the classes a repetedly a lot of times. In ArcMap there is an option to have domains set for the ...
13
votes
2answers
1k views

How to overcome field truncation when converting OSM to shapefile with QGIS?

I am trying to convert an OpenStreetMap file into a shapefile, but I am having problems with the "tags" field being cut-off after 80 characters. With QGIS 1.4, I use the OpenStreetMap plugin to 'Load ...
13
votes
1answer
687 views

How to setup QGIS Master and Stable in parallel on one Linux system?

I mainly use the QGis Master (nightly build) for my Debian Linux and I'm quite happy with it. But for educational and demonstration purposes, I now have to work with the Stable(1.8) version. How can ...
12
votes
9answers
14k views

How to convert KML to shapefile without losing attributes?

I'm new to QGIS and all geoinformation itself but have to work on some difficult stuff. I have a KML file with hundreds of points. To each point there is information, such as Name, Power, Age (it's a ...
12
votes
2answers
548 views

Need a spatial database that can be used by QGIS and R

I'm quite new to QGIS and I'm searching for a simple way to create a Database that allows me to use the tables in QGIS and R. I have a lot of data stored in Excel spreadsheets wich will be used for ...
12
votes
2answers
958 views

Is it possible to manually correct a raster DEM (OpenSource)?

Is it possible, to correct a raster DEM by changeing the raster-cell-values manually, like by "painting"? My DEM (ASTER) have one small error where the elevation is about 300m below the actual ...
12
votes
6answers
6k views

How do I create a shapefile showing footprints of Rasters?

I have around 1,000 satellite images in tiff format, and I want to create a shapefile which will serve as an index to the rasters. This is something similar to a raster catalog, but I do not want to ...
12
votes
4answers
3k views

Shaded relief from DEM in GRASS and QGIS

I have been trying to get a good looking shaded relief model out of GRASS and Qgis for a day or so now and just can't seem to get it. The biggest problem I'm having is the valleys look like ...
12
votes
5answers
8k views

Is it possible to make a DEM from contours in QGIS?

Is it possible to make a DEM from contours in QGIS? I have a shp file (contours) and their heights, can I use QGIS for produce a DEM without using GRASS? I find this creating a dem from contours but ...
12
votes
3answers
4k views

How to join attributes from nearest point in QGIS?

I have two layers with points, call them A and B, each with different attributes. For each point in A I want to join all the attributes from the nearest point in B. Ideally this would also include ...
12
votes
5answers
4k views

Is it possible to connect to ArcSDE using QuantumGIS?

Is anyone aware of any plugins, or any other way to connect and view data from an ArcSDE database in Quantum GIS desktop?
12
votes
0answers
215 views

Qgis 2.0: Disable log messages? [closed]

Is it possible to disable log messages in QGIS Dufour? When I work in QGIS 2.0, log messages increase to more than 2000 and it makes QGIS very slow. Then I save project and open it again, then QGIS ...
11
votes
3answers
243 views

How to update file locations in QGIS projects?

I don't know if there is an answer to this question, aside from the obvious. I have about 30 different QGIS Project files for 30 different clients. Each is saved onto my computer and all their ...
11
votes
3answers
4k views

How to move vectors to specified coordinates in QGIS?

I have a layer of vectors located around, say, (100, 100), and I want to move them to new coordinate like (1000, 1000). How should I do it? Preferably using QGIS.
11
votes
5answers
3k views

Get Raster Values from a Polygon Overlay in Opensource GIS Solutions

I have two layers. A polygon-shape-layer with many tiles and a raster-layer containing CORINE 2006 land cover with many categories in a colourmap. I want to obtain for each polygon in the shapelayer a ...
11
votes
5answers
6k 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?
11
votes
1answer
5k 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
votes
4answers
2k views

How to place elevation numbers on contours with uphill orientation and position?

I want to orient my elevation labels uphill. Is that possible? I'm currently using the labeling tool from QGIS (not that one in layer settings). I want the labels curved and uphill oriented (and I ...
11
votes
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 ...
11
votes
3answers
233 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 ...
11
votes
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 ...
11
votes
2answers
2k views

Is it possible to export GeoPDF from QGIS?

Is their any plugin for QGIS which would help me in exporting the map document as a GeoPDF ?
11
votes
2answers
480 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 : ...
11
votes
4answers
8k 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?
11
votes
2answers
4k 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 ...
11
votes
2answers
879 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 ...
11
votes
2answers
3k views

How to create a new empty vector layer programmatically?

I am new to python and QGIS. I have looked at a few tutorials of python scripts for QGIS. All of them create new vector and raster layers with some existing data source. eg. shapefile or geotiff or ...