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

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2
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1answer
96 views

ECW files not visible in qgis browser (or qbrowser as executed in console)?

version: 2.4.0-1ubuntu2 I'm following a web tutorial at lynda.com about QGIS. In one of the first videos I see there's this preview of raster files. There's the .dem files and the .ecw files among ...
2
votes
1answer
128 views

QGIS suddenly very slow generating atlas on PC?

I have been using happily QGIS for about 6 months, in the last week it has suddenly got much slower when generating an atlas using print composer. I am running QGIS 2.10.1 on a PC laptop (Windows 7, ...
2
votes
1answer
69 views

Can qgis cooperate with phpmyadmin?

Can this two cooperate together? I am asking this, because I have database in myadmin with column for long. and lat. informations. Is there a way to connect qgis with myadmin? Or what type of ...
2
votes
1answer
270 views

Plugins crashing with “No module named qgsprojectionselectionwidget” in Windows?

My Python QGIS plugin works on Ubuntu (at least for me, and all fatal bugs reported so far are solved), but when I run it on QGIS installed from the official 2.10.1 64-bit installer for Windows (on ...
2
votes
1answer
96 views

How to export a CSV with lat lon WKT from a layer which is not in WGS84?

I want to extract a csv with lat and lon coordinates so I select -- Geometry AS_WKT but when the csv is created I see this LINESTRING (277054.55782319931 198725.03588318737,277052.43701817648 198727....
2
votes
1answer
208 views

How to get pixel values of indvidual pixels falling under a poygon to shapefile attribute table or CSV?

I want to be able to write pixel values of each pixel falling under a polygon onto a polygon attribute table or a CSV. I have about 1200 polygons and a georefernced GeoTiff file with NDVI values. ...
2
votes
2answers
118 views

Splitting vector file by date (year) but column containing dates in Day/Month/Year format?

I am using national accident data in QGIS and quite frankly the dataset is huge as it contains every recorded accident between 2005 and 2014. I've split datasets by field for a number of vector layers....
2
votes
2answers
87 views

Is there a QGIS equivalent of inline variable substitution in ArcGIS?

I am working through some analysis in QGIS and need to iterate through a layer of points and buffer each point and then export to a new layer. I want the new layer names to have the values from a ...
2
votes
2answers
234 views

Merging features (lines) in shapefile with same name using Python and QGIS?

I am working with the NHD flowline dataset (USGS) and some of the line features have the same name. I want to merge the line features that have the same name. For example: There are three features ...
2
votes
2answers
117 views

Problems installing QGIS on Windows Vista

I have tried several times on several windows vista machines to install QGIS (both versions 2.10.1 and 2.8) but with no luck. It seems to install fine without any errors but when the installation is ...
2
votes
1answer
62 views

How to reduce points by proximity

I got a layer with over 4 million points. The distance between the points are 1 meter. How can i reduce the data so that no points have less than e.g. 10 meters between them?
2
votes
2answers
234 views

Deciding variables for unsupervised image classification?

The results of an unsupervised image classification may vary A LOT depending on the variables you use from the beginning. These are the variables for the tool in ArcGIS:number of classes, minimum ...
2
votes
1answer
166 views

qgis 2.8.2 always produces minidump on exit

QGIS 2.8.2 on windows 8.1 produces the below error every time it is closed. Anyone have any ideas as to why or possible fixes ?
2
votes
1answer
413 views

How to create a valid QgsVectorLayer from delimitedtext?

I am having trouble loading csv files into layers using QgsVectorLayer(). I know this looks like a repeat, but I have carefully read Create a script to add delimited text layer in QGIS and http://...
2
votes
2answers
87 views

How to load stored composer from project file in standalone QGIS application?

I would like to load a .qgs file and get a composer from it, but I can't figure out how. Is there a way, or do I have to read the xml myself and individually set the appropriate values for the ...
2
votes
2answers
182 views

Store in a python list the attribute table of a vector in QGIS

I'm stuck with a very simple issue.. I've loaded in QGIS (through the py console) a csv layer (no geometry) made of 4 fields and 3 rows: #load the csv layer = QgsVectorLayer("path/to/the/csv", "...
2
votes
2answers
124 views

How to find the irregular polygons in qgis using python

I have a vector shape file and i want to find the irregular polygons. What are the parameters to be considered to check the iregularity of the polygon features? Calculating the perimeter and extent ...
2
votes
1answer
235 views

Copy first row of attributes and paste for each feature

In a newly digitised polyline vector layer, there are 7 columns attributes value that are choosen inside a value map combo-box that MUST be exactly the same for every newly digitised line (I choose ...
2
votes
1answer
185 views

Cartogram not working: “Cancelled by user” - Why?

I am using the QGIS Cartogram plugin, but unfortunately something is not working as it should. First, the demo works just fine. But when I want to create a cartogram with my own layer. But as soon ...
2
votes
1answer
79 views

Difference between qgis.utils and qgis.core?

Please, can you tell me what is the difference between qgis.utils and qgis.core ? I'd like to understand step by step the QGIS API Document.
2
votes
1answer
64 views

How to reproject manually created label positions?

I changed position to some features' labels and I activated the x,y position in the label properties. I saved the layer in .shp and with another projection. Once created a new project with that ...
2
votes
1answer
299 views

Google Maps Openlayer plugin not aligned with the OpenStreetMap building layer in QGIS

I am working on an OpenStreeetMap (OSM) building layer (I download the imposm geojson in city Dar Es Salaam, Tanzania from https://mapzen.com/data/metro-extracts and used the building layer) and the ...
2
votes
1answer
155 views

How to launch Processing tool User Interface using PyQGIS?

I am trying to launch the UI of a processing algorithm using Python script but I cannot find a simple way for it (aside double clicking on it in the process toolbox of course). The plugin is a water ...
2
votes
1answer
202 views

How to find if map layer registry is empty?

In my script I want to open layer named my_layer if it is in the map layer registry. I use following code for it: inputLayer = QgsMapLayerRegistry.instance().mapLayersByName("my_layer")[0] If not ...
2
votes
1answer
52 views

what is the “clip” feature for color ramps?

In the singleband pseudocolor band rendering, there is a boolean checkbox "clip". What does this do? I don't notice a difference in my maps and haven't found documentation for it. Thanks
2
votes
1answer
125 views

How to create a new empty memory layer with fields scheme from other layer in QGIS?

Being a complete noob with python so far, I got inspired by this answer: http://gis.stackexchange.com/a/155988/8202 to dive into it a bit. When creating features in a new target layer from an ...
2
votes
1answer
89 views

Is there a way to integrate my own custom tools into the Processing toolbox in QGIS?

Is there a way to integrate my own custom tools into the Processing toolbox in QGIS? I believe I have found where to strategically hack the stock processing scripts to ensure it picks up my custom ...
2
votes
3answers
66 views

How can I get the UK Land Cover 2007 25m raster data set from Digimap to work in QGIS?

I have downloaded the UK Land Cover 2007 25m raster data set from Digimap (which my university has a subscription to). I have uploaded the data into ArcMap where it works fine, with all 23 classes and ...
2
votes
1answer
74 views

How to dynamically change images in map reports?

I need to make a report about several cadastral parcels which data are contained inside three different tables of a database. Report must contain: Cadastral data taken from the three tables A ...
2
votes
2answers
247 views

Where is the QGIS API action for “deselect”?

Where is the QGIS action for the “deselect” toolbutton in the 'Attributes" toolbar? I do not see this action in the QgisInterface class or do not recognize it by name. Is it missing from iface? I'd ...
2
votes
1answer
151 views

How to avoid a QGIS crash when it is appended a symbol layer in a symbol?

When I run the next code at the Python Console of QGIS with a line vector layer: symbol1 = QgsLineSymbolV2.createSimple({'penstyle':'solid', 'color':'black', ...
2
votes
1answer
375 views

Grass 7 no longer works via the Processing Toolbox on Ubuntu

When I try to execute a Grass 7 algorithm via the Processing Toolbox in QGIS 2.10, 2.8.2 or 2.8.1, I get the following error: Missing dependency. This algorithm cannot be run :-( QGIS ...
2
votes
3answers
157 views

QGIS 2.2 is very slow while saving the edited layers

I am using QGIS 2.2 64 bit in windows 7 system. I have an issue while saving the layers after editing. Its taking more time to save my edits. Some times it's working fine but very often i am getting ...
2
votes
1answer
81 views

QGIS re-write loop efficiently, assign number to every row of a column,

I have a column titled CompanyNam and I need to extract the ownership information. For example, if CEZ is the first company then, I assign to it number 1, then Sokolovska is the next number, etc. If ...
2
votes
2answers
108 views

Rotation field is missing in rule-based renderer in QGIS 2.6

I am trying to do rotation of point symbols in QGIS. I am working with rule-based renderer. In other types of classification there is a button advanced (for example in categorized renderer), where I ...
2
votes
1answer
104 views

How to create a sequence for a table which was created by selecting data from another table?

I have created a new table by selecting data from an existing table: CREATE TABLE polygon2 AS SELECT gid, geom FROM polygon1; CREATE SEQUENCE polygon2_gid_seq; SELECT SETVAL('polygon2_gid_seq', (...
2
votes
1answer
171 views

Adding QGIS feature, that shows coordinates and scale, into a custom application

I'm writing a standalone application using PyQGIS and I'd like to add the QGIS feature that shows coordinates and scale as the cursor hovers over the map. I need to know this mainly in case of ...
2
votes
1answer
77 views

How to add a message bar to custom canvas?

There is a simple code to add message bar to main window in QGIS: iface.messageBar().pushMessage("Hello","World") My question is how to add bar to my custom canvas canvas = QgsMapCanvas() in ...
2
votes
1answer
154 views

QGIS 2.8 OSM download with overpass fails

When trying to download OSM data in QGIS 2.8 I am using a layer to provide the extend for the requested data. The extend basically covers all the countries that share coast line of the Baltic sea (...
2
votes
1answer
99 views

Understanding QGIS scale dependent visibilty?

I cannot understand why the scale dependent visibility function does not want to work in QGIS. I'm using the latest version (2.8.1 Wien) and want to insert diagrams (pie/histogram) to illustrate ...
2
votes
2answers
286 views

QGIS/Python script to generate random points many times

Good day. Can anybody provide a simple code to be run in the Python Console of QGIS (I am using 1.8 Lisboa) to generate X number of random points (say e.g. 5000) over a certain global shape of ...
2
votes
2answers
554 views

How to extend line features up to their intersection point in QGIS?

Is there a tool or plugin in QGIS to extend line features up to their intersection point?
2
votes
3answers
411 views

QGIS joins 2 FIELDS

I have an excel with 4 columns (Region; District; village; number of cases) Have a shapefile with dots for villages with many columns including (Region ; District ;Village) I want to plot the cases ...
2
votes
1answer
124 views

How can I apply a color ramp to a shape file layer in QGIS 2.8?

How can I apply a color ramp to a shape file layer to show something simple like population variance? If this was ArcGIS, I would do it by using the Quantities tab in Symbology but I have been unable ...
2
votes
1answer
276 views

QGIS fails to clip and produces empty shapes

I've seen this type of question a few times and have tried all the different suggestions but no luck. I have 2 layers, one polygon and one line. I want to keep the lines based on a selected polygon. ...
2
votes
1answer
156 views

PyQGIS: How to get the list of valid layers in TOC?

To get the list of TOC layer names I used the approach suggested here: for layer in QgsMapLayerRegistry.instance().mapLayers().values(): print layer.name() But this method is not reliable due ...
2
votes
2answers
42 views

How to list data in the attribute table in the same order as I selected the data?

I have a map that consists of a number of pipes that are connected to each other. Is there a way I can list data in the attribute table in the same order as I selected the data? For example: I select ...
2
votes
2answers
132 views

In QGIS plugin, How do I determine when layer visibility is turned ON or OFF (changed)

I need to update a vector layer's data when the visibility is turned back on. My update does not occur when the visibility is off. To what signal do I need to connect to catch the visibility change?
2
votes
2answers
708 views

What is “Simplify tolerance” in QGIS's Simplify geometries tool?

I am trying to use QGIS 2.8 to simplify vector geometries. But I do not understand the significance of the Simplify tolerance value in the Simplify geometries tool. The documentation does not ...
2
votes
1answer
140 views

Save a table in ascending order in QGIS [duplicate]

Is there a quick way to sort an attribute table in QGIS in ascending order permanently and save it? My third column is an integrer, of course if I clik on the header the table will be sorted in ...