Tagged Questions

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

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2
votes
1answer
477 views

How do I run the nvis tool in QGIS GRASS?

I am trying to follow this workflow: [How to generate a DEM from a countour Shapefile?] and it's running fine, and when I hit view output or view results I end up with a flat raster with shading ...
1
vote
0answers
40 views

problem on loading kriging outputs [duplicate]

My problem is the following: everytime i run ordinary kriging or other interpolation techniques i obtain this error message from QGIS Notice that these are the details for SAGA I would like a ...
3
votes
1answer
284 views

How to create DEM from contours without ArcGIS Spatial Analyst licence?

I'm trying to create a 3d DEM/DTM from a flat contour shapefile which has height data attached to each contour, but I'm not sure how to do this? I've found this post, on creating a dem from contours ...
2
votes
0answers
122 views

Can QGIS display projected coordinate system for map, at same time as lat/long graticule and scalebar in km? [closed]

I am aware of this question, which was posted a year ago, but its accepted answer appears to be a workaround rather than a solution to the issue which is the subject of this Question. I wish to ...
0
votes
1answer
55 views

Export data of points and polygons which are intersected

I have a shp file of roughly 100 Polygon. I also have a corresponding list (including X,Y data) of about 3000 points, in a csv file. Overlayed within QGis the 100 polygons contain about 90% of the ...
0
votes
0answers
85 views

How to run a Processing SAGA algorithm in my own plugin?

After very very attempts to get a result from my plugin which a part of code is presented in the following lines, I noted that in the menu Processing (qgis)/ Options and configuration the path to SAGA ...
0
votes
0answers
68 views

Zonal statistic on recoded raster layer. Information about class value and quantity

i have a raster layer, with 15 different classes. In the raster layer are differrent classes, which stand for windspeed. Then i have a shp-file, where polygons represent urban regions or just free ...
0
votes
1answer
109 views

Is it possible to calculate a value based on values of another row?

I have a point shape file in qgis. For one of the attributes, I would like to offset the values, i.e. the value for point 1 goes to point 10, the value for point 2 goes to point 11 and so on. I see ...
0
votes
1answer
150 views

No module named pyspatialite- plugin:Qspatialite, OpenSUSE 13.1

I cannot run the plugin because of module missing. I can't find that module in the OpenSuse repository, and python community repository. I'm using QGIS 2,0 and OpenSuse 13,1 Where can I find ...
1
vote
1answer
175 views

How can I add height data to a polyline in QGIS?

I want to place a polyline at the correct altitude in QGIS. Is that possible and how do I do this? What I have is a polyline (railroad) and I want to add information on the electrics above the ...
0
votes
0answers
58 views

Reshape tool stops working in QGIS 2

I am using QGIS 2 on Windows 7. I am reshaping some polygons which I am supposed to correct with the reshape tool in the "advancing digitization" bar (). Somehow, after some changes are made ...
7
votes
2answers
467 views

How do I use the Natural Earth SQLite DB with QGIS?

I just downloaded the Natural Earth data in SQLite format from http://www.naturalearthdata.com/downloads/. I had assumed that this would be a SpatiaLite database, but it appears not to be! QGIS is ...
1
vote
0answers
32 views

how to tidy up line intersections

I am very new to QGIS so please bear with me. I am using version 2.0. I am trying to tidy up lines that I have collected using a vertex function on my gps. When I zoom in to the map in QGIS it shows ...
1
vote
2answers
274 views

How to select a multiple field value by expression from the same layer in QGIS?

Using QGIS in the operation 'select by expression' how is the correct expression to select multiple field value? ex. City NAME = ROME and NAPLES (expression is invalid)
0
votes
0answers
60 views

Problem with r.drain in Dufour and 2.1

I am trying to perform to define the shortest route between two points using r. walk, r.cost and r. drain. I have successfully done it using grass under Lisboa standallone living in win7. When I try ...
1
vote
0answers
68 views

Clustering a number of points with the same coordinate around a central point

Is there a plugin in QGIS to randomly distribute points with the same coordinates around the coordinate? Similar to the "shift point plugin", but instead of producing a circle of points the points are ...
1
vote
1answer
77 views

Question about quantum gis, and importing csv point data

I'm trying to add some point data from a csv file (it's in decimal degree lat lon) and overlay over road data that I already have added. The problem is that I can't get it to line up. I'm sure I'm ...
0
votes
0answers
119 views

QGIS 2.0 Plug Repository Connection Failed

I'm trying to connect to the QGIS Official Plugin Repository but the status within the Plugin Manager window is always"unavailable" for the URL - http://plugins.qgis.org/plugins/plugins.xml. I'm ...
0
votes
0answers
87 views

QGIS 2.0 change the raster band from python command

Does anyone know how to change the band of a multiband raster from the python command line in QGIS2.0? It used to be done with something like rLayer.setGrayBandName(1) in 1.8, but this is no longer a ...
4
votes
0answers
90 views

How can I create a form so the user has to be authenticated to access a project?

I have a login form in QGIS and when it is loaded, python gives me an error for, apparently, not recognizing the findchild part. This is due to the fact that the form isn't loaded before the script is ...
1
vote
2answers
73 views

Missing lxml in QGIS 2

I made a QGIS plugin in QGIS 1.8 doing a lot of XSLT transformation and other XML handling with the library lxml. After upgrading to QGIS 2.0 this plugin does not work anymore: "ImportError: No ...
0
votes
0answers
52 views

How do people celebrate GIS Day? [duplicate]

Was looking to hear about interesting or creative ways people are celebrating GIS day. http://www.gisday.com/ There is a map of where some event are happening, but the infowindows are not ...
1
vote
1answer
289 views

3D Polygon Layer Stack with QGIS

I was curious if there is a way, or plugin to visualize a 3D polygon layer stack in QGIS (or another open source package). I have looked at NViz, but it only seems to work for rasters. I have a ...
0
votes
0answers
134 views

QGIS 2.0.1-3 not opening

I've excitedly just downloaded the latest version of QGIS 2.0.1-3 (QGIS Dufour) and now it won't open. I performed the exact same process last night (without problem) on my home laptop (64-bit OS ...
1
vote
1answer
51 views

How to get estimates of areas of overlapping polygons in one shp to another?

Sorry for my ineptitude, but I have two vector shape files of Africa. One has polygons of countries, and one has polygons of tribes a long time ago. What I want to do is to find the intersection of ...
0
votes
0answers
141 views

Unable to render layers in MapCanvas using PyQGIS/PyQt4

I am trying to get some layers into a MapCanvas and style them. I am following the PyQgis Cookbook info here but my code is just not working. I've been spinning my wheels on this for over a week now ...
2
votes
1answer
68 views

How to select vector features with partial (>33%) overlap with another vector feature?

I have a grid and a range map, and would like to select those grid squares which overlap at least 33% with the range map. The range map is a single vector feature. (I'm new to QGIS but have some Arc ...
4
votes
0answers
124 views

Convert Graphics to Vector in QGIS

I am wondering if there is a way to convert a graphic produced from symbology in QGIS to a vector layer (ie: shapefile). I have a point layer with bearing direction in the attribute table. Following ...
0
votes
0answers
31 views

how to remove MiddleButton double click event from qgsmaplegend?

I want to remove the MiddleButton double click event from the qgsmaplegend using qgis python plugin. I am developing the plugin in qgis api 1.8 with python 2.7. i tryed to install an event filter : ...
0
votes
1answer
288 views

Unable to load PostGIS vector layer into QGIS using python cookbook recipe

I'm having trouble loading a PostGIS layer using Dufour (from osgeo4w), using the guide at http://www.qgis.org/en/docs/pyqgis_developer_cookbook/loadlayer.html. I just get the 'invalid layer' message. ...
2
votes
1answer
88 views

Is there no editmode for CSV files? [duplicate]

I load a delimited text layer and it get's visuialized. Unfortunatly I don't know why I can't switch to edit mode. I already worked with similar .CSV files in edit mode before, under the same setup :( ...
1
vote
2answers
42 views

Linking data to road colour scheme

I'm getting started with a qgis map showing the quality of roads in my town. I have various data which create an index of 1-5. How do I link this index data to road data in a map, showing the bad ...
1
vote
0answers
79 views

How can I change the NoData value in QGIS 2.x using the python console

I'm trying to add a NoData value to a single band raster image in QGIS 2.0 using the python console but can't find the right bit of code to do it. Here's what I see on the console: >>> ...
2
votes
1answer
305 views

How to label vector features programmatically?

I am using python for QGIS 2.0.1 and I have a vector layer of points representing the positions of state labels. I want to display the 'state abbreviation' attribute on the corresponding point for ...
0
votes
0answers
27 views

Using a grid of points to generate polygons [duplicate]

I have a csv that has lat/long points for all corners of a perfect grid over an area I am working with. I need to take these corners and generate a shape file with individual polygons for each grid ...
2
votes
1answer
173 views

How to use SAGA ShapesToGrid via Processing in a Python plugin?

I run these lines in my code: vectorlayer_vector = ftools_utils.getVectorLayerByName(inputLayer) Elevation = self.lineAttrib.currentText() cellSize = int(self.linePix.value()) outPath = ...
0
votes
2answers
80 views

Problem loading view from postgres

My problem is loading view table from Postgres. Here is my view table: SELECT h1.gid, h1.st_buffer FROM vmo_buffer_2m h1 LEFT JOIN vodomjeri h2 ON st_intersects(h1.st_buffer, h2.geom) WHERE ...
3
votes
1answer
193 views

How to define a line's width graduated by its attributes?

I have a line shapefile with lots of lines that have different attribute values. I want to present these lines in different widths according to their attribute values without classes but a graduated ...
1
vote
0answers
122 views

Accessing existing instance of qgis from stand-alone python script

For my own data analysis pipeline, I am running a split screen setup with iPython notebooks on one side, generating variables from source data, pushing them to a csv file which qgis then reads/joins ...
4
votes
1answer
122 views

Data defined label alignment option greyed out on new Quantum GIS Dufour

I am trying to customise the positioning of labels in relation to points in a vector file layer in the new QGIS 2.0. In QGIS 1.8 I was able to enter two customised X/Y columns in the attribute ...
0
votes
1answer
71 views

Interpolation without a point layer in QGIS

I have a vector layer with incidence data (i.e. frequencies) and I made a graded color map from this using the above frequencies. Now I am looking forward to creating an interpolated (kriging) map ...
0
votes
0answers
186 views

Select Expression and Field Calculator in ONE STEP with QGIS

I have an Open Street Map Shapefile and i want to use Field Calculator to add information to a field called a800900 according to the field TYPE of street, by different area (field called ID_2). The ...
3
votes
1answer
464 views

Does QGIS feature a tool like ArcGIS Data Driven Pages?

Has QGIS progressed to the point of having a Data Driven Pages type tool set yet? Or perhaps something similar to the old DS MapBook pre arcgis 10?
0
votes
0answers
52 views

Can QGIS be used to develop a vectorization tool?

First off, I don't now the lingo so forgive me if I can't phrase this question using the appropriate language. I am thinking of writing a c++ program that can convert a simple "color map", that is a ...
1
vote
0answers
147 views

How to Export/Print/Save CMYK colored map to SVG, PDF, or PRN/EPS file

I am a beginner using QGIS 2.0.1 on Windows. Following Data-defined Styles in QGIS I fill CMYK values on my map layers, but I cannot Export/Print/Save CMYK to SVG, PDF, or PRN/EPS file. I see only ...
1
vote
1answer
88 views

How to calculate weighted mean coordinates with negative weights in QGIS?

Hi, I'm pretty new to prof. GIS, but have OSM experience. So if I just miss something obvious, please don't punish me :) I have a .CSV file with measurements of wifis along a track. I like to guess ...
0
votes
0answers
77 views

what happens to attribute table while performing union, intersection, difference of gml and shp file in QGIS

I am trying to do an analysis of the data conversion from shapefile to GML file using QGIS. For the analysis I have taken a point, line and polygon file. I first took a shapefile and converted it into ...
0
votes
0answers
26 views

Style Manager Symbols and Ramps Missing in QGIS 2.0 [duplicate]

This is very frustrating. I already posted a question about the missing color ramps in QGIS 2.0. I´ve even installed the development version without success. No color ramps available, and I have to ...
5
votes
2answers
1k views

Standalone applications using QGIS and environment variables

I've tried going through IRC to see if people can help me out with this, but the medium seems a little clumsy for making any answers clear, so I'm going to try this instead. I would like to program a ...
0
votes
1answer
186 views

How to define correctly the Grass region in Qgis

I know that my question could be pretty basic for some of you. I am trying to learn GRASS. I have some raster layers and a vector file in EPSG 32614. Using the grass plugin I defined a new map set, ...