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

learn more… | top users | synonyms (1)

0
votes
0answers
44 views

Adding Raster Layer in C++ application always result in layer invalid

I am trying to add a raster layer in c++ application with QtCreator and QGIS 2.6.0. My code is as follows: QgsRasterLayer * layer = new ...
2
votes
1answer
58 views

area elevation distribution with QGIS

I have a raster DEM and a polygon covering a part of it. I need an area-elevation distribution (i.e. how many m2 are in which elevation interval). 20m intervals will be fine. I cant figure it out.
2
votes
1answer
30 views

Percentage of a polygon at, or less than, a specific height (supplied by a raster)

I am using QGIS to process some LIDAR data. I need to be able to define the area of a pond with respect to its depth (i.e it is 100m^2 at 32mAOD and 500m^2 at 33mAOD). Is there a way of finding the ...
2
votes
0answers
48 views

QGIS returns “invalid layer” when adding a WMS layer

I want to add a WMS layer in my map. I select the server and obtain the list of layers that are published there. I select one of them (the problem is the same with all layers), but QGIS does not load ...
1
vote
1answer
70 views

How do I make my map use a set of coordinates

Right a little background. I've made a custom google map with the google map api which has a few functions that work well within it - one specifically is limiting the user on what they can view within ...
1
vote
0answers
35 views

How to merge DMAs using QGIS — Creating Custom Regions?

What I am trying to do might seem basic, but bear with me as I am just hacking my way through a lot of this space. What i am trying to do: I am trying to create a new .shp file of custom regions. ...
2
votes
1answer
150 views

QGIS print composer, DMS grid when SRC is not in decimal degrees

I have a QGIS project where the layers are in projected SRC, and when I go to the print composer to draw the grid, the units are in millons of meters, and I want them in decimal degrees. Is it ...
2
votes
1answer
104 views

J2000 to WGS84 in QGIS?

How to transform Earth-Centered Inertial J2000 CRS to WGS84 CRS in QGIS? I searched J2000 in spatialreference.org, however nothing found. I don't know the proj4 string of J2000. Any advice would be ...
2
votes
0answers
100 views

Menu actions in QGIS 2.6 feature attributes

I would like to ask about new menu 'actions' in feature attributes which appears in new QGIS 2.6. This menu shows 'actions', defined for the layer but I am wondering if it is possible to add some ...
0
votes
1answer
173 views

Apply an sld to a vector layer in OpenLayers

I'm trying to apply an sld style to a vector layer in Openlayers. I already took a look on google and here and I got a lot of informations, but still I don't manage to achieve the result I'm looking ...
1
vote
1answer
92 views

With QGIS Plugins/PluginBuilder, how to prevent 2nd instance of Plugin from starting

I am using QGIS 2.6.0, with PluginBuilder 2.0.3 [checking the version, I just noticed that the 2.1.0 update is available] I am writing a plugin; it installs and runs. While running, I am able to ...
3
votes
0answers
328 views

QGIS 2.6 Brighton - Graduated Symbols

I can't get graduated symbols to show in QGIS 2.6. This is what I have done. I have two fields of type integer, saved as a shape file which I have tried to import as a shape file and as a secondary ...
3
votes
1answer
125 views

Add button to custom standalone QGIS application

Im able to implement zoom in and zoom out functionality as described in the PyQGIS developer cookbook using a tool bar. I would like to have buttons that display above my map canvas layer and have the ...
3
votes
1answer
157 views

How to prevent users from removing QGIS layers?

I need to prevent users from removing layers. In my plugin code I use the following to achieve that: QgsMapLayerRegistry.instance().layersWillBeRemoved.connect(self.dontremovefunc) def ...
1
vote
2answers
95 views

Using QgsRasterCalculator

I'm trying to make a sum of n rasters and create a new one using QgsRasterClaculator, the problem is, every time the code reaches processCalculation, it makes QGis close and create a dump file. I ...
1
vote
1answer
60 views

Compute nearest points to other points using GRASS

I have a layer of address points and a layer of polling stations. My task is to determine the three closest polling stations to each address on the street network. I think that the answer is in ...
3
votes
1answer
179 views

PROJ.4 - General Parameters: +no_defs

within a QGIS-course I would like to tell a bit about the proj.4 parameters. However, I´m not sure about the "+no_defs" parameter. The proj.4 website (https://trac.osgeo.org/proj/wiki/GenParms) ...
3
votes
1answer
62 views

Incorrect placement of a MrSid file in QGIS

I have a map saved as MrSid file which when loaded in QGIS displays as a southern hemisphere location despite being in the UK. When looking at the .sdw file the northing is positive but in QGIS it ...
0
votes
0answers
113 views

Automatically creating index features for a strip map in QGIS

Is there a free/open source equivalent ArcGIS's Strip Map Index Features geoprocessing tool? I'd like to use QGIS's "Atlas" mapbook functionality, but creating the index layer manually would be ...
2
votes
0answers
52 views

Is there a way to change floating toolbar orientation?

Is there a way, within QGIS 2.*, to stop the interface from trying to snap in floating toolbars (as attached pic)? I want to maximise canvas space, but the interface keeps on wanting to grab my ...
2
votes
0answers
133 views

How to create dynamic maps based on updated attributes in SHP file

I am novice GIS'er. I can create maps and do basic transformation of the SHP file using QGIS. I also succesfully applied formatting based on attributes. I am able to add new attributes to SHP file in ...
2
votes
2answers
153 views

Is there an algorithm for transforming from CGCS2000 to WGS84?

Is there an algorithm that supports transforming from CGCS2000 coordinate to WGS84 coordinate? CGCS2000 is China Geodetic Coordinate System 2000. Any advice would be thankful!
1
vote
2answers
46 views

Reduce squarish effect on group of polygon

I am trying to represent the average speed of some ship in the north of Mediterranean sea. I am interested in aggregate the speed information by zone. The raw data I am working with are .shp with ...
1
vote
0answers
119 views

QGIS installation failed - requires matplotlib which has been installed by Anaconda

Is there any way to specify python environment variable to solve this? When I tried to install QGIS on my machine - mac OS 10.9 and Anaconda has installed numpy, scipy, and matplotlib, I got the error ...
0
votes
0answers
116 views

Extract Aerial Imagery using QGIS

I need to create city-wide (Warsaw in this case) aerial based map, pretty detailed (clearly visible buildings and possibly 1-pixel-sized cars. So far the only way I found is: Using this method: ...
0
votes
0answers
124 views

How to create a map in Pulkovo 1942 with grid?

I have a problem with coordinates when I change projection. With WGS 84 it's fine, I have normal, geographic coordinates. But when I'm changing to Pulkovo 1942 (I need a map of Poland), coordinates ...
0
votes
2answers
43 views

Error with layer.pendingAllAttributesList

While coding to obtain individual layers' attributes (field) list, I am stymied by the code. I can identify a specific layer: MyLayer = QgsMapLayerRegistry.instance().mapLayersByName("TestPoint") ...
1
vote
1answer
22 views

How do I ensure polygons are properly displayed when using 'on the fly' CRS transformations in QGIS 2.6?

QuantumGIS 2.6.0 (Windows 7 64-bit) I have created a PostgreSQL POLYGON as WGS84 (CRS 4326). The polygon is a series of points around (but not actually on) the edge of the map. This is a rectangle ...
1
vote
2answers
294 views

QGIS Python Script - Routing along Waypoints [closed]

I used Anita Graser's script point_layer_to_route.py which worked like a charm until I updated to 2.6. With QGIS 2.6 I always get objects without any features. Can anybody tell me if he/she had the ...
2
votes
2answers
70 views

fit a wrap column in the print composer QGIS 2.4

i have an attribute table in the map composer, and the field i want to see is quite long...so i wrap it. but the field width is not fitting this new length. how can i do that. is qgis prepared to do ...
0
votes
1answer
65 views

Is there a QGIS plugin that can transform tabular data to graph?

I have a CSV file with water level measurments in a well, taken once a year for 40 years. Is there a way to show this data as a graph (x axis being the date and y axis the water level) in QGIS?
3
votes
1answer
73 views

How to insert some holes in a polygon?

I have a problem with QGIS digitizing advanced tool plugin. I have a landcover-like shapefile. I have to perform some corrections on it, and I have to cut or split some polygons. I want to insert some ...
0
votes
1answer
139 views

How do I use a filter on an uncached WFS layer in QGIS?

I am trying to create a filter to show only specific features based on an attribute query within a WFS using QGIS. This works fine when using the standard WFS loader and creating a filter (based on ...
1
vote
1answer
73 views

How can I avoid displacements in exportet JPGS from QGIS 2.2? [duplicate]

I observed a small but annoying problem for a long time now. I have to design maps/plans of survey areas for work including maps where a satellite image is printed under a vector-layer showing the ...
0
votes
1answer
189 views

Is it possible to have auto-updating area fields?

I'm using QGIS 2.4.0 and I've noticed some problems with the derived area and the $area field. Firstly, I have a polygon which is a filled ring, inside another polygon. The derived area, and therefore ...
0
votes
1answer
62 views

How to set attribute to selected field?

I am trying to create a temporary point layer in memory using the following python code. # create layer vl = QgsVectorLayer("Point", "temporary_points", "memory") pr = vl.dataProvider() # add fields ...
1
vote
0answers
188 views

With QGIS, why use QT Designer tools for creating Slots/Signals/ etc, if plugin coding can do it alone

I am curious why there is facility within QT Designer to create signals and slots as, to my surprise, I did not need to do this. All of the necessary coding was accomplished completely within the ...
2
votes
1answer
47 views

Reprojecting from Wagner VII using QGIS

I have a shapefile in Wagner VII projection (well, the proj4 string really only is: "+proj=wag7 +datum=WGS84 +units=m"). I'd like to reproject it to WGS84 (EPSG:4326) using QGIS 2.6. However, when I ...
2
votes
2answers
190 views

Looking for guidance to create a hydrological map with QGIS and/or GRASS

I have QGIS and GRASS installed . Basically i need this program for making maps something like this: https://www.youtube.com/watch?v=5HuPX7JS7ZA I downloaded DEM from ...
1
vote
1answer
153 views

How to label line features using python code?

I used the following code to label the line features(roads) in a layer.It works in the console, but not by python code(application) It works for the points too. What did I do wrong? Any help would be ...
3
votes
1answer
52 views

How to label states in QGIS with county-level shape

Hi I want to label state names in QGIS but my original shape file is built in county-level. If I simply label them with ``State'', my map shows multiple labels in each state as my original file (one ...
2
votes
3answers
129 views

Which monitor for working on printable maps?

I have a 24" monitor with a resolution of 1920x1080. Mostly I'm working on printable maps in QGIS. The size of some labels is sometimes smaller then 5mm on the final printed map. At my monitor this ...
0
votes
0answers
77 views

Is it normal that the installation of QGIS removes some graphical packages (12.04LTS)

When I install qgis with qgis.org deposit or ubuntugis ppa, apt wants to remove all of these packages : The following packages will be REMOVED: libgl1-mesa-dri-lts-quantal ...
2
votes
0answers
72 views

SHP, SHX and DBF files became empty (zero byte) overnight on QGIS

This literally happened overnight. I was working on a shapefile in QGIS 2.4 last night but my files (SHP, SHX and DBF) all become zero byte this morning. Has this happened to anyone before? How ...
1
vote
0answers
83 views

How to find a distance from a point to a polyline in QGIS?

Please show a sample Python code of finding a distance between a point to a polyline in QGIS. (without any plugin)
3
votes
0answers
35 views

QGIS isn't displaying dates in the attribute table

I have a QGIS project that links to data in a Postgres database. For some reason, QGIS is not displaying any data in date fields. The date fields appear to be fine in Postgres and I have performed ...
0
votes
1answer
163 views

How to add mdb geodatabase layer (feature class) to QGIS project using python?

I want to add a feature class of a personal geodatabase mdb to my qgs project by code (a plugin I am working on). I am using a command similar to that used for adding shapefiles, but this is not ...
4
votes
1answer
295 views

How to display multiple fields as labels if one field is null?

I am having some issues trying to show multiple fields for a single label in QGIS. In QGIS2.6, attempting to display labels for a feature consisting of multiple fields results in an empty label if one ...
1
vote
1answer
318 views

QGIS OpenStreetMap plugin: download failed. Server replied: bad request

I am trying to download Open Street Map data using the OpenStreetMap plugin in QGIS, and getting the following err: I'm kind of new on geoprocessing, so I have no clue what is going on here.
2
votes
1answer
29 views

How to allow the user to place a point as input for a geoprocessing model?

Is there an analogue to Esri's "Feature Set" in QGIS modeller. I am interested in creating a model that allows the user to place a point feature on a map as an input variable for a geoprocessing ...