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

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2
votes
0answers
497 views

How to resize a polygon (rectangle or circle) in Qgis?

Yes I used the Rectangles Ovals plugin to create a rectangle then rotate it and move it nto position. But if you want to resize it that is where the fun starts because it is just a polygon with four ...
2
votes
1answer
659 views

How to create a QGIS action which copies features between layers?

i tried (i never tried before...) to write a simple python code like action in QGIS on my "XXX" vector layer that: open a layer "YYY" copy the selected feature on my "XXX"layer paste the selected ...
1
vote
0answers
54 views

How to make gdalbuildvrt available in processing modeller?

I would like to make a model in QGIS that builds a virtualraster from several raster files. Unfortunately the gdal function is not available on the modeller. So, my question is: how to make this ...
1
vote
3answers
754 views

How to create random point in according polygon for each dataset entry in a list (with R)

I have an area divided into polygons, and a dataset of observations which has a common field with the polygon layer. I now would like to generate a random point for each dataset entry within the ...
3
votes
2answers
594 views

How to select features with NULL Geometry from Shapefiles?

I have been given a Shapefile that contains records with NULL geometry, along with records with non-NULL geometry. This situation appears to cause problems in QGIS (1.8 and 2.0) when editing the ...
1
vote
0answers
92 views

Is it possible to cut/filter all layers to an area of interest in one step?

The problem of working with a lot of data (about 100 layers). Very slow computer, rendering long. Vector -> Geoprocessing Tools -> Clip a very good tool, but replace the 100 layers is very high and ...
1
vote
1answer
595 views

How to change the color of red edit-polygon or purple snap-confirmation?

I'm having trouble seeing the purple or pink snapping confirmation when drawing a polygon because the temporary polygon is red (QGIS 2.0.1). Also the vertices in edit mode are also red. I looked ...
2
votes
0answers
85 views

How to sort legend values efficiently in QGIS print composer?

Using QGIS 2.0, I have a vertical color legend for raster values, created in the print composer. I want the values sorted in descending order from top to bottom, which appears to be the reverse of the ...
2
votes
1answer
110 views

How to make marker line thicker in QGIS?

I'm mapping railways, find that the usual cross marker line is so thin it doesn't show up in Print Composer at web resolution, and can't find any way of making it thicker, only the main line. Is there ...
5
votes
0answers
221 views

How to create a chart of elevation using points?

I am using shapefiles with basic information including the x-, y- and z-coordinates. I want to see how the objects (in this case points, which are finds from an excavation) are scattered along the ...
1
vote
2answers
2k views

Convert .asc format into shapefile

I've got some data from "http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp" and it is in *.asc form. To process them I need to convert them to shapefile (need to merge them all into one shapefile and ...
3
votes
1answer
199 views

Converting map image to GIS

I’m very new to GIS, and I’ve been reading a lot of manuals and information, but I thought I’d ask a couple of questions here. One of my major hobbies is drawing maps of a completely imaginary ...
1
vote
1answer
117 views

How to perform intersect operations in the Field Calculator in QGIS?

How to use the Intersect function? How would I specify to REPLACE layer1.field1 with layer2.field2 WHEN layer1.geometry INTERSECTS layer2.geometry Is that feasible in QGIS?
2
votes
0answers
116 views

How to copy the contents of an attribute from one vector layer to another one that touches it or intersects it?

I have 2 layers that intersect, called layer A and layer B. Layer A has an attribute (X) that I want to copy wholesale (for the whole layer) to layer B, so that when object A1 intersects object B1, ...
1
vote
1answer
147 views

Problem loading raster QGIS 2.0

I am very new at GIS. I am trying to load a raster so that I can complete a tutorial on georeferencing. The raster file is a jpeg. However, whenever I try to load the raster, it gives me solid colored ...
1
vote
0answers
331 views

Qgis Server - Ubuntu 13.04 - Can't create a directory [closed]

I'm Portuguese (sorry about my English) and this is my first post here. It would be very useful to me, to discover how to get to work qgis server+ qgis web client. I'm a Windows user, so, I followed ...
2
votes
1answer
233 views

Batch Update Fields in Field Calculator or Model

I have a dataset of block-level census data that I clipped to an Illinois State Senate district. To update the data (e.g. for population) I'm applying an area multiplier, i.e taking the area of each ...
1
vote
1answer
303 views

How To Show Percentages By Coloring Polygons in QGIS?

I am trying to produce a map with QGIS that has counties shaded according to the percentage of people born in a US Region. For example, counties with a high percentage of people born in the South ...
1
vote
1answer
142 views

raster to ascii in QGIS

I have a raster file (DEM or .tif), but I need to transform it into a .txt file (ascii). How can I do this in QGis (Quantum Gis)? Thank you so much!
2
votes
1answer
153 views

heat map of density ratio of 2 layers of points

I have 2 vector layers of points: one with a point for each house in the city (thanks to osm.org), roughly equivalent to population one with a point for each case of cholera in the city I'm trying ...
5
votes
1answer
661 views

Using the Processing Framework in QGIS 2.0

I am writing a plugin for QGIS 2.0, and I want to use the processing framework to call some functions. When I open the pyhton console inside QGIS, I am able to call it like this: >> import ...
5
votes
1answer
404 views

Why does ManageR and rpy2 not work in QGIS (1.8.0-Lisboa)?

I have been trying to get R scripts to function and ManageR to work within QGIS (1.8.0-Lisboa). (Windows 7). Python2.7.5. Two problems indicated that R was not working in QGis. First - when I run an ...
3
votes
1answer
2k views

What expressions for QGIS field-calculator?

I do not understand what language I have to use in field-calculator and labels on QGIS: SQL or Python? And where I can find the possible script/expressions to use? in the image you can see the ...
5
votes
1answer
137 views

Finding the best locations for bee hives within a specified area (QGIS)

I would like to find fixed positions for bee hives within an orchard to ensure complete pollination of the trees. Is there a way to do this in QGIS? Example: The orchard area is 2 hectares (I have a ...
2
votes
1answer
47 views

Where did XYTools go [duplicate]

Where can I find the repository for XYTools plugin? I have tried several repositories and got messages that it was permanently removed!
3
votes
1answer
366 views

Colorify polygons in a pythonic way in Qgis

I want to addd a Layer and give the layer a color for the border and for the filling. With the code below i am possible to achieve a color for the border, but a did not found a solution to give a ...
4
votes
2answers
856 views

Sum many netCDF rasters

For the first time, I am using NetCDF data files containing daily data about soil moisture at a global level. I want to be able to obtain monthly mean value of soil moisture for each grid cell. ...
2
votes
1answer
280 views

how to remove and change qgsvertexmarker in QGIS using c++ code?

In QGIS following code is used to set marker at point A. QgsVertexMarker * marker = new QgsVertexMarker(mPlugin->iface()->mapCanvas()); marker->setColor(Qt::black); ...
1
vote
0answers
109 views

How to do dissimilarity index in GIS?

Can anybody help me to find out how dissimilarity index can be used for transport study, and is there any method in QGIS or ArcGIS for Desktop through which it can be performed ?
6
votes
1answer
203 views

Calculating a Unique ID on a Subgroup of Polygons

I would like to assign a unique ID to polygons in a dataset. The catch to my issue is that I would like polygons that fall within a polygon to have the same unique ID. My example is related to ...
6
votes
2answers
86 views

Define projection at the record level

Hopefully this isn't too dumb a question, but is it possible to define projection at the record level, instead of a whole layer or table? I want to create a "project" database for all the work my ...
2
votes
1answer
3k views

How to open a “Raster Dataset” in QGIS

I want to open a "Raster Dataset" in QGIS. In ArcMAP I can just add it like shown in the Screenshot (only the raster shows up). If I am trying to do this in QGIS. However there I don't see the ...
4
votes
1answer
168 views

QGIS 2.0.1 linking table issue, MSSQL 2008 database

I'm trying to link tables in QGIS 2.0.1 and MSSQL 2008 database. I can link them but when I try to open the attribute table QGIS throws an error and shuts down creating a *.dmp file. I saw that ...
3
votes
1answer
361 views

How to sum up all field values in QGIS modeler

I am building a model to generate two zones around a point, a 250m-buffer, and a ring of 250 to 1000m, where i recalculate values from an other layer according to the intersections share. The purpose ...
2
votes
1answer
687 views

How can I show points on the same coordinate as e.g. a bigger symbol in QGIS?

I use QGIS 1.8 for mapping archaeological findings. Some of the findings within one layer are located on the same site and therefore have the same coordinates. Therefore you just see one point instead ...
3
votes
1answer
655 views

How to join 2D polylines and DEM into 3D polylines?

I got a simple question but could not find a satisfactory answer yet: I have a road network in 2D/PostGIS and a DEM. I want to turn the road network into 3D by retrieving the Z-value from the DEM. ...
2
votes
0answers
196 views

Our best table-analysis with GIS? [closed]

Sometimes I think about possible analysis using GIS models (I use QGIS 1.8), and I always think about few types of visualization techniques: demographics, traffic flows, distance ones... Thanks to ...
1
vote
0answers
179 views

Error: basic_string::_S_create, (trying to use .ecw files)

I have a problem, after resolving my problem with: .ecw is not a supported data file. I am in a new one. When I try to load an .ecw file in QGIS it says: basic_string::_S_create
2
votes
2answers
5k views

How to add csv file in QGIS 2.0 using Delimited Text Layer Plugin?

I used to import csv files in previous versions of QGIS using the format below, but when I upgraded to QGIS 2.0 the delimited text layer plugin was changed and I can't import the file anymore. The ...
3
votes
2answers
3k views

How to load MrSID raster layer in QGIS on Mac OS?

I have just upgraded QGIS to 2.0 and now I can't load my SID raster layers. I now remember that getting them into 1.8 was a performance but I can't remember all the details. I have downloaded the ...
3
votes
0answers
172 views

Handling non-spatial data for QGIS projects with Camelot

Most of my projects include data which is non-spatial or which is point data and can be managed by a regular relational database. Previously I found Manifold and ms-access were a good combination ...
2
votes
0answers
657 views

QGIS connecting to ArcGIS world imagery - not loading correctly

Have connected QGIS to ArcGIS World Imagery using python console as described on http://www.northrivergeographic.com/qgis-adding-an-arcgis-rest-service. QGIS Seems to connect and make a raster layer ...
1
vote
2answers
1k views

OpenLayers plugin for QGis problem with maps loading

I am new in GIS. I use QGis 2.0.1 with OpenLayers plugin downloaded from official repository. When I click to Add OpenStreetMap layer the map is not showing and load process is neverending. What is ...
2
votes
1answer
322 views

Can I Turn Off or Remove Map Layers in QGIS Print Composer

The title pretty much says it all. I have a base map in QGIS that I am using with several Print Composers. In one of the Print Composers, I don't want one of the layers to show up. Is there any way ...
2
votes
1answer
75 views

QGis - QgsComposerScaleBar - nearest km

I added a QgsComposerScaleBar to a QgsComposition. I wish to have segment rounded to the nearest km but I don't know how to achieve this. Thank you in advance.
1
vote
0answers
299 views

Couldn't load PyQGIS, QGIS 2.0.1 on Ubuntu 12.04 Precise

After upgrading to QGIS 2.0.1 I still get the error: Couldn't load PyQGIS. Python support will be disabled. Traceback (most recent call last): File "", line 1, in File ...
0
votes
2answers
1k views

JP2 fails to open in QGIS and GDAL

I am trying to open a JP2 file in QGIS and it fails, and I'd appreciate any advice to try and track down the cause of the issue, be it with my system or with the file itself. The file is a HiRISE ...
1
vote
0answers
61 views

QGIS mapserver - fails to display some raster images

QGIS 2.0.1 running on Linux, with mapserve support. Randomly, it seems, some raster images simply fail to display. No errors, just no image (well actually the mapserve returns a blank white image). ...
1
vote
2answers
714 views

Calculating millions of distances with Road Graph

I'm new to GIS but thanks to the answers I got in another question here on GIS stack exchange I was able to increase my knowledge significantly. This question is related to an earlier question I asked ...
3
votes
2answers
681 views

Access all plugin from QGIS Modeler (Sextante)

I read that it is not possible to access to all of the installed QGIS plugins from the Graphical Modeler (QGIS 2.0.1). It would be great, in defining the model in the Graphical Modeler, if the user ...