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

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5
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2answers
392 views

Spatial Analysis with Factors/Classifications

When doing analysis on spatial data with associated information that is numeric, it is possible to use techniques such as Kriging or Interpolation or Cluster Analysis to find out interesting ...
1
vote
0answers
215 views

How to handle/ avoid intersect errors when clipping the difference between two layers?

Using QGIS + Grass, I've added a shapefile of coastline and islands to my map. I then buffer this shapefile to create a coastal zone of a known width. At this stage the buffer consists of the ...
2
votes
1answer
806 views

How to apply a graduated renderer in pyQGIS?

Just trying to run the following code already given in the pyqgis cookbook to create graduated colors symbology (as in example with 2 classes) I define the source info for the shapefile but when I ...
1
vote
1answer
385 views

Why do I get 'KeyError: 0' when using Line Intersection tool?

I'm using Quantum GIS version 1.8.0-Lisboa and trying to create intersection point using Intersection tool. (Vector -> Analysis tools -> Line Intersections ) But when I do that for my shapefile, It ...
0
votes
1answer
347 views

How to convert a finished project in QGIS to PDF

I have finished my project and need to convert it into a PDF file. How can I do it?
1
vote
1answer
321 views

matching georeferenced jpg with GPS data in WGS84 [closed]

I have imported my georeferenced jpg which I believe (on the basis of metadata in xmml file) to be in the NZGD2000 TM coordinate system. metadata: Origin: 1.76759e+06,5.94938e+06 Pixel Size: ...
6
votes
1answer
456 views

How to label a lot of nearby points?

I am currently working with a lot of points of which every point has to be labeled. I am already using the "Easy Custom Labeling" tool to move the labels and create lines to connect points with ...
0
votes
0answers
715 views

How to resample a raster in QGIS?

I've got a boundary file that I would like to resample the raster file from a 30m grid to a 10m grid inside the boundary file. When I try and do it in Qgis or Grass all I get is one big raster cube ...
0
votes
0answers
291 views

How to change shape file's extent in QGIS

I have created a network from 3 shapefiles using GRASS. While haveing problem to perform a network analysis with it, I've been told that the extent of the network shouldn't exceed that of the original ...
0
votes
2answers
608 views

Python module “shapely.wkb” missing

I am trying to follow a tutorial from here http://qgistips.spatialthoughts.com/2012/12/find-neighbor-polygons-in-layer-in-qgis.html#more I have downloaded the relevant python script and edited it as ...
6
votes
1answer
411 views

QGIS line style

I found the latest QGIS has a great tool to create complex styles, however looks like one small but very useful thing is missing, or I can't find it. I'm trying to create a line style something like ...
1
vote
1answer
269 views

Polygonize function doesn't overlay the shape file over the raster file

To convert the raster into a shapefile I use raster->conversion->polygonize but QGIS doesn't open the new layer overlayed the first (the raster) but reflected above it. I read this question ...
3
votes
1answer
341 views

color gradient (or color ramp) in Arcgis and Qgis

I am currently working on my thesis and I would like to ask you: does anybody know the mathematical formula that calculates the color gradient in Arcgis and Qgis? In other words, which mathematical ...
1
vote
1answer
242 views

Displaying only points within a polygon I created in QGIS?

Thank you in advance for any advice you might give me. I am new to qgis and believe what I'm asking is probably fairly basic. I am trying to map policing activity in NYC for two areas: one area in the ...
0
votes
1answer
91 views

Should a GDAL Plugin be the same version as GDAL aready built into QGIS

Should a GDAL Plugin be the same version as the GDAL that's aready built into the QGIS version installed? Or,can another different version of GDAL be built and it installed as a Plugin for QGIS, ...
3
votes
0answers
162 views

How to achieve better Dissolve results?

I applied the Vector>Geoverarbeitungswerkzeuge>Auflösen (Dissolve) on a zoning plan (see picture zoning plan). I used the attribute village name as the dissolving criteria. The resulting geometry for ...
3
votes
1answer
214 views

Can I color different layers with the same pseudocolor color map?

I have multiple DEM layers in my map (downloaded from atlas.louisiana.gov/lidar), but I cannot seem to get the colors to line up. You can see in the attached image that the colors are not continuous ...
2
votes
2answers
119 views

What specifically is an 'attribute' and how does it work with the related chart?

I'm a new QGIS user (and GIS technology in general) and I'm trying to learn its fundamental features. I have a big dilemma about vector shapefiles, and points in particular: basically, I don't ...
4
votes
1answer
677 views

How to break (both) lines at their point(s) of intersection in QGIS?

I'm working with a road network where some of the road segments cross each other but no point is inserted at their intersection. Is there a way to break these line to shorter lines at their points of ...
3
votes
5answers
1k views

Batch processing DEM rasters in QGIS/GDAL

I am attempting to add relief shading to map using .asc raster files, following this tutorial. It works well, but I have only tried it on single tile of raster data which is 20x20km. I want to ...
0
votes
0answers
105 views

How to access the rules of QgsRuleBasedRendererV2 using python?

I can't get access to the rules of rule-based renderer, python says there's no attribute "rootRule", though documentation says it should be (http://www.qgis.org/api/classQgsRuleBasedRendererV2.html) ...
3
votes
0answers
59 views

Programatically reorder layers in qgis? [duplicate]

Possible Duplicate: Sort layers in QGIS table of contents? I write a qgis python plugin ,and i try to connect keybord keys to reoder layers in qgis . Are there a method in qgis allows me to ...
9
votes
1answer
191 views

Advanced labeling formatting (centered and different sizes)

I would like to place the elevation-number of a point in a different front size and centred under its name: Is that possible? (That is my actual labeling: label || '\n' || elevation) Thanks!
4
votes
1answer
79 views

Reduce number of vector field arrows in qgis

OK, now that I have figured out how to get my vector fields in qgis, I can't figure out how to reduce the number of vector arrows on the map. Is there a setting for how many vectors are sampled? ...
2
votes
2answers
628 views

Couldn't load plugin fTools due an error when calling its classFactory() method

When I start qgis I get a python exception: Couldn't load plugin fTools due an error when calling its classFactory() method ... 309, in _import mod = _builtin_import(name, globals, locals, ...
1
vote
1answer
213 views

How do I create rendered vector field in qgis

Perhaps I am misunderstanding the "vector field renderer" and "VectFieldCalc" plugins, but I have no idea how to make a vector field of arrows, with directions and magnitude. I have the data loaded ...
4
votes
2answers
589 views

Can I download the current version of QGIS if I am running Mac 10.8.2?

I am taking an introductory course in GIS at my university and my teacher recommended QGIS for Mac users. Unfortunately, I haven't been able to download the software. I just upgraded to Mac OS 10.8.2 ...
1
vote
2answers
596 views

Import Civil 3D DEM to ArcMap or QGIS

I have some survey data exported from Civil 3D in both dtm and dem formats. I thought the I would be able to use the dem more easily, but I think the format is different from a USGS DEM. Is it ...
2
votes
0answers
149 views

QGIS 1.8.0 suddenly sluggish/unusable on Gentoo

QGIS 1.8.0 has been working fine for a number of months. Then I upgraded my system generally, which possibly included upgrades to xorg-server and QT, and now QGIS is sluggish/unresponsive to the point ...
4
votes
2answers
121 views

Creating space at intersection of two links

I have a shapefile consisting of two links which are crossing over each other. I want to create an empty space at the point of intersection of the two links. As of now, I have been manually doing ...
4
votes
1answer
61 views

How to deliver an additional Python Library with own Plugin?

For my own plugin I need a special library (pyexiv2) to write a comment into a jpg file (PIL does not do that). When I want to share my plugin in one of the repositories in the future, what would be a ...
2
votes
1answer
581 views

How to save WMS getFeatureInfo points to a layer?

This may be a poorly worded question, because I am not sure of the exact terminology, but I'll give it a shot. I have imported a vector layer from a WMS server into QGIS. I am able to query the ...
2
votes
1answer
1k views

How do I get and install the latest version of QGIS in Ubuntu?

I'd like to get the latest 64-bit dev build of QGIS on my Ubuntu setup. How exactly do I go about it? I assume it's some kind of arcane terminal command...
1
vote
3answers
204 views

Is it possible to create a PostGIS sequence to populate Area column of a polygon

I've created Postgres/PostGIS sequences before to assign unique gid values when a feature is created in QGIS but is it possible to create a sequence that will automatically populate an area column? ...
6
votes
4answers
1k views

How to find dead-ends in a road network

I'm trying to remove all the dead-end roads in a road dataset (lines) that are less than 100m long. How do I identify roads that are dead-ends (no exit)? The 100m part is easy. I know how to use Arc ...
0
votes
1answer
131 views

There is no menu bar on Mac OS 10.7.3

I installed the latest version of QGIS on Mac OS 10.7.3 with 2 additional frameworks (GDAL Complete and GSL) but there is no main menu bar (not at the top of screen, not at the window of QGIS). Where ...
6
votes
5answers
842 views

What is the Typical Workflow from QGIS to Publishing Programs?

I have been playing with using Inkscape to combine my CAD title block and the map project created in QGIS. I was curious to understand what a typical workflow might be to Inkscape or another post ...
5
votes
3answers
361 views

Polygonize vegetation area from Landsat7 RGB using QGis / Bilko?

I'm trying to extract the areas with vegetation as a polygon-shape from a landsat7-image, 30m resolution, RGB, using QGis 1.8 or Bilko or (hopefully in the near future) ArcGIS. The area is in Northern ...
4
votes
1answer
173 views

How to install QGIS on a 2006 iMac?

I would like to know if there is QGIS version for a 32bit Mac (Intel Duo core processor). The newer versions require a 64bit processor.
1
vote
1answer
184 views

QGis compile with Qt Creator error

I followed the steps in this article http://linfiniti.com/2011/06/using-qtcreator-with-qgis/ to compile QGis on Ubuntu 12.04 64bit with Qt Creator. I got the latest source for master with git. I get ...
7
votes
2answers
168 views

How can I force text to appear underneath other layers in QGIS?

To emphasise one particular polygon area, I have used rule-based styles (QGIS) to apply a 50% transparency white fill to every polygon but the one I am interested in. This polygon layer is above all ...
1
vote
1answer
109 views

QGIS CSV file sorts low numbers as high

So I have numbers that range from 5 to above 50, and when I sort these from least to greatest, the numbers less than 10 are treated as higher than anything else. It also does the same when I try to ...
0
votes
0answers
100 views

trying to make a point to polygon attribute join with a many to many match

I am trying to match US charter schools to noncharter schools in QGIS. I have constructed a buffer of 10 miles around each charter schools and then tried a join attributes by location match with non ...
1
vote
1answer
486 views

How to fix the “Snap tolerance” error message in QGis?

I am trying to use the "Delete part" tool on a shapefile. While I am starting to use it, an error message shows up : "Could not snap segment. Have you set the tolerance in Settings > Project ...
1
vote
1answer
147 views

How to Add New Freehand Shapes and Data in QGIS?

I'm new to QGIS. Can anyone either direct me to a good tutorial or explain? I want to draw freehand new shape layers on to Google Earth to map vegetation types and embedded data for each feature. I am ...
3
votes
1answer
709 views

Hydrologic analysis with sextante-saga in qgis

(rough translation): Hi, I want to do hydrologic analysis of a DEM with sextante-saga in qgis. I found the plugin and the needed algorithms in SAGA, enabled them in the sextante toolbox, but when I ...
4
votes
3answers
282 views

How to subset X number of features from Shape file in QGIS

I'm looking for a means to take a rather large Shape file and split it out into separate, smaller shapefiles based on number of features. So for example, if I have a file with 1 million features, ...
4
votes
2answers
1k views

Spatial distance analysis in QGIS

I'm quite new to QGIS and trying to figure out how to analyze the following problem. I have three layers: settlements point layer with 253 entries waste treatment facilities point layer with 24 ...
1
vote
1answer
148 views

Why won't QGIS let me write to a file?

I am writing a QGIS Python Plugin. I am trying to write data to a file using with open("filename.txt", "w") as f: f.write("file text.") QMessageBox.information(None, "Test", "Written to file.") ...
1
vote
0answers
272 views

DLL problem with PyQGIS

I am having problems with Python Shell importing the module "qgis.core". When I type "import qgis.core" the Shell ("idle.pyw") gives me this error: Traceback (most recent call last): File ...