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

learn more… | top users | synonyms (1)

0
votes
1answer
14 views

Creating Stream Order

I'm new user of this software, please can somebody guide me, how to calculate stream order in QGIS or GRASS GIS, step by step.... mean commands and how to calculate watershed in this.
1
vote
0answers
13 views

Connect two contour line with calculated line lenght

Is it possible to make plugin for qgis like PEGGER for arcview 3.2? Problem is, how to make path over contour lines with a grade in percent Formula is: K= e*100/G*M ; K=10*100/0.08*10000=1.25m K- ...
1
vote
0answers
34 views

Calculating vector area in QGIS

I have calculated a viewshed (ZVI) in OpenWind and opened the raster in QGIS I have then converted the raster to a vector When I open the attribute table there are 4682 rows (features) and there is ...
1
vote
1answer
31 views

How to create a text file containing layer names in QGIS?

My QGIS ToC contains layer groups and some layers that do not belong to any group. I would like to create a text file containing the name of those layers that do not belong to any group. Is there an ...
3
votes
0answers
21 views

QGIS algorithms do not work on copies of shapefiles?

I'm using QGIS 2.6.0. I'm trying to run various algorithms such as "SAGA/Shapes-points/remove duplicates" & "SAGA/Shapes-Grid/Add grid values to points" through the sextant toolbox. When I run ...
2
votes
1answer
19 views

Error converting a raster to polygons

When I am converting a raster using the polygonize tool, I get this error: ERROR 4: 'C:/Users/Vitor/Desktop/Cartografia EE_Portimo/COS RASTER/cos_raster_reeditada.tif' does not exist in the file ...
1
vote
1answer
40 views

How to automatically create 10,000 sets of random points for further analysis in QGIS?

I'm using QGIS and would like to know if I can automate generating multiple sets of random points and mean distances? I have a data set consisting over 600 coordinate points for Mistletoe across ...
0
votes
0answers
10 views

How to relate data values from two raster layers?

This is my second posting ! 1 Background I have a number of ASCII files containing a set of single values X, each set in a 1km x 1km grid – the start of each file looks like this: NCOLS 700 ...
0
votes
0answers
7 views

How to calculate interval areas in raster?

I would like to know if is possible and how can i calculate the areas from class intervals in one raster? All help is appreciated, Best regards
3
votes
1answer
37 views

How to display OSM relations (in QGIS) from osm2pgsql populated PostGIS DB

I have a PostGIS DB populated with OSM data (osm2pgsql, standart.style). Now I would like to display a hiking trail (http://www.openstreetmap.org/relation/51855). It would also be fine, if I just ...
5
votes
1answer
233 views

Is it possible to have dynamic layer names in QGIS project?

I have a QGIS project with layers, based on PostGIS SQL queries that use current date. Since the data in the database changes, these queries return different data every new day. Is it possible to ...
0
votes
1answer
21 views

Tools to export shps from Oracle database

What open source tools could be used to export shapefiles from an Oracle database. I have tried using QGIS but it does crash way too much.
0
votes
0answers
15 views

How to get the same cell size after and before been rasterized [duplicate]

The following information were used for rasterization of the land cover of Nigeria but got different cell sizes. The input cell size and the measured cell size of the rasterized are not the same. ...
0
votes
1answer
28 views

Got different cell sizes from a rasterised data

I'm trying to rasterize the Land cover data of Nigeria which was obtained from FAO database. During the process of rasterizing the land cover data, I used the following information which gave ...
2
votes
0answers
17 views

Why does my “Zoom to selected rows” Shortcut not work in QGIS 2.6.0?

I´ve changed a shortcut, in this case "Zoom to selected rows". But now it stopped working. The new shortcut never worked and the originally as well is not working now. The icon gets activ when doing ...
4
votes
1answer
36 views

QGIS batch shp transform

I have a large number of shape files in OSGB (EPSG:7405), with no .prj file that I would like to convert to WGS84 (EPSG:4326). Can you let me know if this is possible in Qgis and, if so, how, and, if ...
1
vote
1answer
30 views

Is it possible to create tiles with transparent background using Qtiles?

I had created the tiles from shapefile using qtiles plugin in QGIS and that shapefile layer is a label layer created using MMQGIS plugin. But the thing is I want that tiles with transparent ...
1
vote
1answer
10 views

Open and split a 4 channel RGB picture

How can I split an 4 channel rgb pic in qgis? With the value tool I can see 4 channel. I tried to use the RGB to PCT tool but I always get an error (File "C:\PROGRA~1\QGISBR~1\bin\pct2rgb.py", line ...
1
vote
1answer
26 views

How to compute tabulate intersection in QGIS?

I have a base layer of census data in census tracts (polygons). I'm looking to intersect those tracts with a buffer layer but I only want to include those census tracts whose area is over 50% within ...
1
vote
2answers
48 views

Merging shapefile layers not working in QGIS?

How do i merge different vector layers in to one shapefile layer In QGIS version 2.6
0
votes
0answers
11 views

If statement using QgsRasterCalculator

So in the sequence of my previous question (Can't use Raster Calculator with two different rasters), I am stuck again in my project. With my source rasters, I created 3 different outputs using ...
2
votes
0answers
22 views

QGIS raster data from vector and raster files

Excuse me if my GIS terminology is a bit shaky, and for the length of the post, as I am a complete beginner to GIS and this is my first forum post. I am using QGIS 2.6 32bit on Windows 7. 1 My data ...
2
votes
0answers
25 views

QgsRubberBand with holes

I tried to create a QgsRubberBand object with holes, but failed: rb = QgsRubberBand(iface.mapCanvas(),True) geom = QgsGeometry.fromWkt("POLYGON((0 0,4 0,4 3,0 3,0 0),(1 1,3 1,3 2,1 2,1 1))") ...
3
votes
3answers
71 views

Alternative to OpenLayers plugin for QGIS?

Are there any alternatives to OpenLayers plugin to have Google / Bing maps for QGIS projects? I need an high quality cartography (both aerial and street view) but OpenLayer plugin do not allow to ...
1
vote
1answer
26 views

How to make rectangle selection on QgsMapCanvas?

I have this code for create and open raster map: if(QFile::exists(rasterFileName)) { QFileInfo myRasterFileInfo(rasterFileName); m_pRasterLayer = QSharedPointer<QgsRasterLayer>( ...
1
vote
0answers
8 views

Transparency on black/white raster after clipping in QGIS?

I'm new to this forum and QGIS. I'ld really appreciate it if you could help me with my problem, since I couldn't find any solution online but people experiencing the same issue. It seems as if this ...
1
vote
0answers
25 views

Soils sampling. How to make polygons from interpolated points?

My goal is to make a shape file with polygons for variable rate fertilizer application within a farm field. I have a point shape file with soil sample values (pH, P, K and so on) and a line/polygon ...
2
votes
1answer
56 views

Use 2 different symbologies on the same feature QGIS

I have data symbolized with different categories Each category has a field for different symbology style like the table below. Is it possible to visualize the same category of data with in ...
1
vote
2answers
49 views

How to add 2 layers in qgis and display them at the same time

I added 2 layers in qgis using python but only one layer is shown on canvas. After clicking (anywhere on the canvas) both layers are displayed. layer = ...
-1
votes
1answer
21 views

How to decrease elevation values of DEM using open source GIS sotware? [on hold]

I am newbie in QGIS, but I was wondering how to decrease elevation dem DEM using QGIS? Can QGIS do that? Or anyone of you can tell me any open source GIS software to perform that?
1
vote
0answers
29 views

Connect to QGIS 2.6 Python Plugin function via button on custom feature form

I am trying to connect to a QGIS 2.6 Python plugin function via a custom feature form button. On my feature form, I'm attempting to do a few things : enable the updateButton only if the ...
1
vote
1answer
21 views

QGIS 2.6 : Programmatically setting key value pairs for ValueMap widget

Using QGIS 2.6 and Python 2.7 on Windows 7, I am trying to programmatically insert key value pairs into a ValueMap widget via a csv file. Issue is that some of the values are properly inserted and ...
2
votes
1answer
26 views

Label interior of polygon boundary

I'm using QGIS 2.6.1 and would like to label US state polygons such that each border is lined with the label of its two states. Something like this: It appears that the current labeling engine ...
1
vote
0answers
30 views

Reprojecting a population raster from LAEA to lonlat

I have a population density raster from the EEA which is based on the CORINE land cover 2000 data. ...
2
votes
1answer
29 views

QGIS Change treeview categories in browser(2) panel

The main categories of the treeview in the browser panel seem to be hard coded. Is it possible to 1.) add, delete or rename categories (e.g. instead of "Project home" name it "Data") 2.) link ...
1
vote
0answers
20 views

QGIS and GRASS r.fill.dir processing times

I am new to the open source software and have performed analysis in ArcGIS in the past. I am learning as I go on this processes for OS. I am trying to calculate stream order (strahler) on a 1 gig ...
1
vote
0answers
28 views

Use QGIS as API [on hold]

I would like to develop a simple application to use raster and map from a server. Is it possible to use QGIS as API to display map and raster? I also know that QGIS use API and library like ...
1
vote
0answers
21 views

QGIS polygon - filling a polygon gap

I do not use Python, I'm afraid. I need to fill in a polygon gap for this map of Scotland. Here is the gap: How do I fill in this gap? I have already tried drawing another polygon inside the gap ...
2
votes
1answer
21 views

How to display variable number of images associated with one point on QGIS

I have a set of point locations. I have a set of images with reference numbers. I'd like a way to easily see the images associated with the location, using QGIS. This is for my own use rather than ...
1
vote
0answers
20 views

QGIS Processing modeller fails when running field calculator

I have a problem running a model that I use to create columns with the coordinates for the start and end points of a line. This model used to work but now the model gives me this error :Algorithm ...
1
vote
1answer
28 views

Is it possible to print one item legend item in italic in print composer?

Is it possible to have one item in italic font (species names) and the rest in "normal"? I use QGIS 2.6. The legend consists of two items which should be written normal (trap positions and ...
1
vote
1answer
44 views

Load the raster image which is in TIF format using QGIS API

I am quite new inthe field of GIS. I am interested in is to load the raster image which is in TIF format using QGIS API I have followed the steps given the in the follwing link to load shape file ...
0
votes
0answers
16 views

Error in the attribute table after intersection [on hold]

After intersection the attribute table is incomplete. What is the problem? Thank you
1
vote
1answer
37 views

QGIS 2.6.1 Brighton/ Grass pluggin r.stream.xxxx

I just updated my OSGeo4W and now have QGIS 2.6.1 and GRASS 6.4.4 and am trying to get strahler stream order. I am figuring out GRASS 6.4.4 GUI by itself but GRASS is easier withing QGIS, however, I ...
0
votes
0answers
9 views

QGis crash when open georeferencer generated image

I'm trying to georeference an image with the georeferencer, QGis creates the geotiff, I can open in other image viewers but when I try to open in QGis it crashes. A friend tested in arcgis and it ...
1
vote
2answers
35 views

Free solution for an intranet geodatabase for point data, connectable to QGIS / MapInfo

I have a plenty of point measurements - thousands of points with date/time, gps, measured values etc. I would like to make it possible to put all my particular datasets (can decide whether shp or ...
1
vote
0answers
15 views

Update WFS Layer with QGIS - Commit errors

In QGis: Importing WFS Layer from Server, changing Attributes, trying to save. I get Commit errors: Could not commit changes to layer ah_neu:mylayer. The geoservers logfile says: 2015-01-21 ...
2
votes
0answers
21 views

QGIS 2.4 graphical modeler add field: error executing algorithm

I have to add more than 20 fields to a lot of shapefiles. I used to do it with the tablemanager plugin. Beside it is time consuming, misstakes can be made. So I want to automate that procedure ...
3
votes
1answer
95 views

How to create a missing dbf file for shapefile?

I have a shape file (shp) which is missing its dbf. I tried to load this into Postgis using shp2pgsql and got the could not open shapename.dbf error. I opened it in QGIS, without issue, and ...
1
vote
1answer
22 views

How to zoom to selected feature with QGIS Python Console

I want to select a feature by ID and zoom to it. I tried the following but the canvas doesn't change. Any ideas? canvas = qgis.utils.iface.mapCanvas() cLayer = canvas.currentLayer() cLayer.select(51) ...