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

learn more… | top users | synonyms (1)

5
votes
1answer
915 views

How to create a custom data viewer on top of QGIS?

I was exploring the possibility of creating a simple Data Viewer based on QGIS. I would like to create an simple application that will open QGIS up with a limited set of tools & menus. QGIS would ...
5
votes
4answers
5k views

Advanced colour palette for raster data

I'm working with satellite date namely chlorophyll and sst. Each geophysical parameter generally has standard colours to represent them. I'm importing geotiffs into Qgis and I'm having difficulty ...
5
votes
2answers
1k views

Looking for an explanation of QGIS Edit Widgets

I have noticed "Edit Widgets" under the Quantum GIS and would like to know in detail the use case and usage of this widget. For any opened vector file, under the Properties -> Fields Tab, for every ...
5
votes
1answer
1k views

QGIS - export a project with dependencies

I was wandering if there was a way to save a specific project with all layers as dependent files to make it easy to share with collaborators. for example, create a zipped or non-zipped folder ...
5
votes
1answer
3k views

How to fill my column with consecutive numbers

I m very new to Qgis, so forgive this simple question. Searching in older topics didn t help either.So: I make a new column in my attribute table and it has a default value(for example 0). I want to ...
5
votes
2answers
6k views

snapping polygons and lines

I recently downloaded QGIS on a Mac OSX 10.7.4 (lion) and purchased a master map shape file, of a particular area. I am trying to divide it into polygons following features on the master map vector ...
5
votes
2answers
3k views

Statistics or simple pie chart in Quantum Gis

Does anyone know how to perform pie charts based on table values within QuantumGis and include them in the print outs? thanks a lot
5
votes
1answer
272 views

Seeing QGIS Python Commands

When learning MapBasic I found the most useful way to learn how to do certain tasks was to do them using the GUI and then watch the MapBasic window in MapInfo to see how they were achieved in code. It ...
4
votes
1answer
192 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 ...
4
votes
1answer
405 views

QGIS 2.4.0 Chugiak How to remove topographic effects like shadows from landsat image

I am using QGIS 2.4.0 Chugiak on my windows 8.1, for classification of landsat 5-7 image that contains hilly mountains with dense forest and 60% area are plains. I am classifying through ...
4
votes
1answer
259 views

How to find a single point furthest from any road?

I have a road layer of a country. What method or plugin would you suggest, to find a single point furthest from any road (but as you can see, there is a coastline, so points in the sea can't count) ...
4
votes
1answer
907 views

How to transfer styles from QGIS to ArcGIS?

We have a QGIS project that has symbols for a lot of different lines. Data comes from a geodatabase that is accessible to both QGIS and ArcGIS. We now want to use the symbology of the QGIS project to ...
4
votes
0answers
334 views

Weather conditions forecasting / interpolation

I'm trying to carry out weather conditions interpolations. I have information of 92 weather stations for 800,000 km2. As you can imagine the extension of land is huge and I need some kind or weather ...
4
votes
1answer
825 views

How to create an extent indicator in QGIS 1.8 print composer?

I'm looking to put an inset map for my main map frame onto my map layout in QGIS print composer. I would like it to indicate the extent and location of the main map on a larger regional map. This ...
4
votes
1answer
100 views

Why are raster z-values changed when reprojecting?

I have raster data with height values (z). When I try to reproject/warp the raster to Gauss Kruger 3, the z-values are changing (several meters). (The data is already GK3, but I have to reproject ...
4
votes
2answers
483 views

How to convert numeric fields into strings with leading zeros?

I'm trying to define an action in Quantum GIS using on of my fields but I have some problems with its format. I have a numeric string like '5' and I need to have a format like '005'. I've tried ...
4
votes
2answers
2k views

QGIS Server limitations?

QGIS Server seems to be fairly simple to setup and create services, however I'm wondering if there are any limitations with using it opposed to MapServer or GeoServer. My current server ...
4
votes
1answer
466 views

QGIS - Add a combobox to a toolbar

Is there a way to add a combobox to a toolbar for QGIS? So far I can only find examples that add buttons. I found this tutorial which seems to explain how to do this with general PyQT but haven't had ...
4
votes
1answer
2k views

Installing QGIS on Mac OS 10.7. “The GDAL framework is required.”, and yet I have it

what did I miss? I'm trying to install QGIS on my MacBook (Mac OS 10.7). I'm following these instructions: https://sites.google.com/site/eospansite/qgis-installation/installing-qgis-1-6-on-macosx It ...
4
votes
2answers
2k views

Can QGIS automatically load an SLD with a Shapefile?

I have SLD's/lyr files with my shp/gdb files. They all have the same name except for the extension. Is it possible for me to force qgis to load the sld with the shp so that I don't need to manually go ...
4
votes
3answers
2k views

Using CityGML data with ArcGIS Desktop or QGIS?

I'm looking for advice on how best to use the CityGML data-structure and GIS (preferably ArcGIS/QGIS). I've read through their website and wiki and saw a list of software here that can be used to view ...
3
votes
2answers
143 views

How to define layer's CRS and avoid the CRS dialog in PyQGIS?

There is an existing Shapefile, which I want to add. At the moment my code looks like: self.iface.addVectorLayer(self.shpFilePath, "Track", "ogr") It works fine, but i want to define the crs ...
3
votes
1answer
174 views

How to clip a single layer of overlapping polygons in QGIS

I have a single layer of polygons. Some of the polygons overlap. I wish to make a new layer of just the parts of the polygons that overlap. What is the best way to do this in QGIS seeing it's ...
3
votes
1answer
583 views

How to create a catchment from a point using a DTM raster in QGIS?

I need to find a better way to delineate a catchment from a given point on a watercourse using a DTM - currently I am either using FEH, or if the catchment is too small using contours to draw ...
3
votes
1answer
1k views

How to install LAS tools in Processing for QGIS 2.4?

Does anyone know were the processing menu moved in QGIS 2.4? Specifically I am trying to install the Lastools box for QGIS following these instructions. ...
3
votes
2answers
930 views

Is it possible to give 2d contours a Z-height from their attribute table in QGIS? (Or ArcGIS?)

I have a contour data file downloaded from UK Ordnance Survey, which gives 2d contours of an area in gml format (also supplied in .shp format) with the heights of each contour attached to the ...
3
votes
2answers
558 views

Georeference vector linework

I'm new to GIS and a lot of searching didn't answer my specific question so far, so I hope someone can help me here. What I want to do is creating a small web application to visualize election ...
3
votes
1answer
262 views

QGIS: Colour GPS track by speed

sorry íf I might ask this question the 101 time, but I didn't found anything with google or SE. I have a CSV file with WGS84 trackpoints and visualizing them with QGIS textplugin works fine. The log ...
3
votes
0answers
269 views

PyQGIS joining a dbf to a shapefile [duplicate]

I am trying to join a shp and dbf file using the PyQGIS API. The code I'll use is below: from PyQt4.QtCore import * vector1 = QgsVectorLayer("path to dbf file", "test1", "ogr") id1 = vector1.id() ...
3
votes
2answers
461 views

How can I turn islands into individual features in QGIS?

I have what seems like a pretty straightforward task in QGIS: I have a shapefile that, in some cases, groups multiple separate landmasses into a single feature. For example, the Hawaiian islands are ...
3
votes
3answers
17k views

How to convert x y coordinates to longitude latitude using QuantumGIS?

I'm working with this downloadable shapefile that has X Y coordinates. They are akin to '3672187.92698000, 534175.72095400'. I would like to convert them to longitude latitude so they are more like ...
3
votes
1answer
3k views

How to manually edit point coordinates in QGIS?

Is there a tool for shapefiles or a QGIS plugin available, which will enable me to edit the coords of a point manually ? ("tool" -f1 "Tsunami Gauge"-move x1.abcdef -to x2.ghijkl) I do have ...
3
votes
1answer
831 views

Handle add new feature event and/or access feature before commit?

Is it possible with PyQGIS to catch "add new feature" event before commiting changes on the layer? or at least to access new features before commit.
2
votes
2answers
85 views

Is it possible to sort the features by an attribute programmatically?

I have written a PyQGIS script that loops through an attribute table and finds duplicated values in a target attribute field. My technique requires that the attribute table is first sorted by the ...
2
votes
2answers
198 views

Do I need to remove older versions of QGIS?

I have installed up to 2.6.1 of QGIS on my computer. Is it recommended that i remove all older versions? Will it cause conflict if they remain?
2
votes
3answers
548 views

Draw line between points from multiple datasets

I have 2 point datasets and want a tool or script to draw a line between all points in one dataset to all the points in the 2nd dataset. Is it possible? I have tried ESRI "Point Distance" and ...
2
votes
1answer
278 views

How do I access QGIS program settings programmatically?

I am trying to temporarily enable the option in QGIS using PyQt4 to suppress the attribute dialog popup after a feature is added. I found an example in the cookbook but it doesn't indicate how to get ...
2
votes
1answer
191 views

Split polygon into lines

I have a polygon layer which looks like this . I used the QGIS multiparts to singleparts tool and also polygon to lines. In both cases i got this type of result . I want to extract polygon into ...
2
votes
2answers
3k views

How to draw bar diagrams on the map?

I need to draw simple histograms in QGIS version 1.8 linked to data from an imported DB. I need a double bar diagrams (eg: male/female - in/out) but I only find the possibility to set pie charts. Is ...
2
votes
1answer
2k views

How to find the watershed area for each point in the river network using DEM?

Update#1: Thanks, Micha, I have followed your instruction and successfully use the modules in GRASS. I use r.watershed to get the basin raster and the drainage line: and I use r.water.outlet to get ...
2
votes
1answer
1k 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 ...
2
votes
1answer
2k views

Is it possible to place a point at a coordinate in QGIS?

Is it possible to place a point at a coordinate in qgis? I have a map, using irish grid reference and wish to place a point at an exact 6 digit coordinate. Is it possible to do it. Previous to this ...
2
votes
1answer
773 views

QGIS identify features button issue

Is there anyway to get the Identify Features button in QGIS to automatically select a layer and provide the information without having to highlight it first in the layers TOC? MapInfo and ArcGIS ...
2
votes
1answer
1k views

encoding problem with QGIS 1.8 and CSV import

I have following problem with QGIS 1.8. Lisboa (standalone installer, Win 7 Pro 64bit) - I import CSV - text in CP1250 separated with ";" and using "," as decimal separator. I correctly set the ...
2
votes
1answer
1k views

How to create a grid constrained within a polygon in QGIS?

In QGIS I have created an irregularly shaped polygon. I can create a grid based on the maximum extents of the polygon via Vector>Research Tools>Vector Grid. However, what if I need the grid to ...
2
votes
2answers
15k views

How to convert coordinates from meters to decimal degrees?

I have a shape file. The coordinates (Lat/Long) are projected as meter (555000, 155000). But, I want to re-project it to decimal degrees(51.523666, -0.07467). How can I do it with ArcMap or Quantum ...
2
votes
2answers
500 views

Which labelling tool/engine in QGIS will be supported in the long term?

Why does QGIS appear to have two labelling tools? (Note this is not new and old symbology, but that...) there are two different GUIs, one in the toolbar (which gives the Data Defined Settings option) ...
1
vote
1answer
177 views

What is the purpose of some functions and files in QGIS Python plugins?

I'm just trying to understand the architecture of a QGIS Plugin created with the QGIS Plugin Builder, as well as the workflow and the linkage among generated files. If possible, I'd prefer a diagram. ...
1
vote
1answer
171 views

How to use the MMQGIS plugin through the Python console?

I know how to make Hub Lines using the GUI, I want to know how to do the same using the Python Console, a tutorial would be great. Thank you
1
vote
1answer
500 views

How to add the attributes of selected features to my new layer in pyqgis

I am trying to create a layer from the selected points coordinates. I am drawing a circle to the coordinate of selected points. I also need to add initial attributes of my selected features to my new ...