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

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80 views

Using Advanced Python Calculator in QGIS Modeler

I'm trying to create a column with integer values based on a small function that basically uses conditional statements. In short, a reclassification. My attempt below: def getValue(Etat): if Etat ...
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1answer
227 views

Installing QGIS on Mac OS X 10.6

Could someone kindly explain how to get QGIS (any stable basic version) on my old Mac (OS X 10.6)? I'm completely new with QGIS and all the instructions that I can find beats me.
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1answer
42 views

Exporting output in ASCII from a QGIS model

I'm trying to find a geoalgorithm in QGIS's Graphical Modeler that can convert and export a vector to ASCII. Could anyone enlighten me if there's an option for that? Perhaps through some script but I ...
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1answer
175 views

How to detect coordinate reference system (CRS)? – I cannot display two vector layers in QGIS at the same time!

When I in QGIS try to display layer (a) together with another layer (b) that differ in their CRS it doesn’t work. Both are vector shapefiles. I have tried both with using QGIS ‘on the fly’ CRS ...
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0answers
71 views

QGIS Pipe Flow and Aerial Photo

I am completely new to QGIS and We had the survey pick for drainage pipes and pits. We have Upstream and Downstream invert level for each pipe. Wondering if any one could help with step by step, set ...
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0answers
177 views

QGIS - Pop-up menu not displayed when right click on a layer in layer tree view

I'm developing a custom QGIS application using the QGIS API. I've been using the API provided with QGIS Brighton (Version 2.6.1) and have been developing the application in Python in a Windows 7 ...
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1answer
126 views

Problem with writing input and output for QGIS user script

I need to write QGIS script, which removes features with same value of specific attribute - in output will be only features with first occurrence of value. I know, how to check duplicity, but I don't ...
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1answer
266 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. ...
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1answer
165 views

QGIS working directory

I was just wondering what's the best way to organise QGIS projects. My problem is that I work across different platforms, Mac, Win and Linux and the project contents are stored with links to the files....
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2answers
96 views

Interactive “for each item in … do …” in QGIS?

How does one interactively run a basic looping batch construct in QGIS? for each {feature} in {features}: do {thing} with/to {feature} save/export/display {result} Where: {features} ...
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0answers
37 views

Number of intersected features from one layer per feature from second layer

How can I get number of intersecting features from one layer per feature from second layer using any component from QGIS 2.8 (GRASS, SAGA, Python scripting...)? Result should be stored in new ...
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1answer
338 views

Is it possible to use non-printable characters as delimiter for text file layer in QGIS?

I am trying to import a Delimited Text File Layer from a .csv file in QGIS. Because this caused a lot of errors, I posted a question here and got the hint towards using ASCII non-printable control ...
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1answer
47 views

How to change decimal places when using graduated renderer?

The classifications given when I use the graduated renderer on QGIS under 'Layer Properties' are to 4 decimal places, and I would like none. I know I can use the rule based style and create my own ...
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1answer
105 views

How to change the “application_name” of a PostGIS-connection in QGIS?

PostGIS offers a view called pg_stat_activity, where you can see all the active connections to the database. This view includes the interesting column application_name. When a connection comes from a ...
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3answers
126 views

Strange coordinate system [closed]

Here's an extract of a feature from the web that I converted to geojson using qgis. However, the coordinates are not standard are at all and when trying to actually preview it on the web it fails, ...
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1answer
144 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 ...
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2answers
174 views

Is it possible to split a picture taken with a regular digital camera into real spectral RGB channels?

I have no idea how the sensors inside a camera work. I know I can take jpeg and separate the R, G and B channels but I have no idea whether these channels are the real red, blue and green in visible ...
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1answer
146 views

How to remove group filter applied via Python-console (setSubsetString) of QGIS?

I need to quickly applie (and then change/remove) the same filter for about 100 layers in my QGis project (all put together in one group). Since there is no implemented solution right now (a feature ...
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1answer
32 views

Adding New Linear Feature using QGIS?

I am new to QGIS (2.6.1) and am having trouble adding a new linear feature to an existing layer. I have set tolerances and digitized the vertices of the line and it terminates with a large green X at ...
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0answers
77 views

Create a sript for “point sampling tool” of QGIS

Is there any way to create a python script to the "point sampling tool" plugin from QGIS? I have a very large number of Netcdf files which I want extrat the values from pixels to a irregular points ...
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1answer
69 views

in a single vector layer I have a three of polygons with different field values (e.g1,2,3). How Can I color each field value polygon differently?

In a single vector layer I have a three of polygons with different field values (e.g1,2,3). How Can I color each field value polygon differently? To explain a bit more my three polygons are showing ...
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1answer
81 views

Bing Aerial metadata in QGIS

I am using Bing Aerial imagery within QGIS through the openlayers plugin. How can I find the dates of the images that are within the map canvas? Thank you Becky
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2answers
330 views

Is it possible to not show node in editing mod QGIS

I actually have a plugin that allows me to draw on a vector layer (I made it based on the FreeHand Editing Plugin). When a mouseMoveEvent is detected, it creates a new point on the vector layer and ...
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47 views

QGIS File Geodatabase Vertices missing

I am adding Data from a File Geodatabase to QGIS. Everything is working fine, but the drawing of a specific Line subtyp (first image). It looks like, QGIS can not draw the circle properly. An export ...
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2answers
904 views

QGIS 2.8 starts with an error and I am not able to run Python console

I have installed QGIS 2.8 - Wien on Linux Red Hat 7. Unfortunately when I start the application I got this python error: {Couldn't load plugin 'processing' from ['/usr/share/qgis/python', '/home/...
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2answers
154 views

Need a vector format that is editable in QGIS and supports >10 character column names

For reasons, I need to create a new column in a vector shapefile with a name longer than 10 characters, and export to mapinfo TAB format. I know .shp's don't support >10 character column names, so I'...
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1answer
35 views

Classify values from table

I would like to classify several values from a vector table with field calculator in 5 classes based on standard deviation. Example: value = 3.3, mean = 2.5, std deviation = 0.7 and class #5 is "mean+...
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0answers
43 views

How to automatically refresh canvas after saving layer edits

After saving a layer edit in QGIS 2.8.2 (Win7) I've to press F5 or change the map section to refresh the canvas. This is quite annoying when working with dynamic PostGIS views. Is there a way to ...
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1answer
123 views

How can I implement animation with lines using QGIS TimeManager?

Among all the examples I saw, I can only find those with animated dots. I need to implement a time slider based on each link's capacity, and display different colours according to the magnitude. ...
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0answers
118 views

Zonal Statistics for multiple rasters

I'm trying to create a timeseries of raster data (one layer per year) by polygon (Administrative regions). Is there any way in QGIS to perform Zonal Statistics for multiple years (without having to ...
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1answer
20 views

Hub Distance - 'Layer not found'

I am trying to calculate the distance between a polyline (River) and multiple points. However after installing the MMQGIS plugin and running a Hub Distance between the two layers the error comes up '...
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1answer
197 views

Using the Function Editor to replace special characters

I am attempting to use the new Function Editor within QGIS 2.8.2. I have a field called LAND_NAME with hundreds of rows. What I'm trying to do is find and replace all "special characters". In ArcGIS, ...
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1answer
268 views

How to display map tips only for one layer?

I'm relatively new to QGIS. I added the hover labels to my map using the Map Tips. My issue is that it makes hover labels for EVERY layer on my map. I only want it to make labels for one layer. Is ...
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1answer
15 views

QGIS Graphical Modeler Help editor does not save

Is there a special way to save whatever text you're writing in the Help Editor for a QGIS Model? I've been trying a few times, apparently just after I click ok, even though I immediately click "save" ...
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0answers
58 views

Python snippets from QGIS

Out of curiosity and perhaps for practical reasons, is there a way to obtain Python snippets from QGIS 2.8 the same way you do in ArcGIS? Please don't redirect me to some other question that looks ...
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1answer
198 views

How to fill a hole - with islands within?

In QGIS I have simplified a layer. At the end of the simplification process (using GRASS v.generalize), my final layer "lost" a polygon: see white space in image: How can I recreate a polygon which ...
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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 ...
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1answer
148 views

Change page setup in composer window using the QGIS API

Is it possible to use the QGIS API to change the orientation within page setup in the composer window. We have a plugin that builds a map template based on user defined options. When they choose to ...
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1answer
240 views

Why can't I copy values from a virtual field to a non-virtual field using PyQGIS?

Using the python console, I am trying to copy values from a virtual field into another non-virtual field. Both fields are integer types but I get NULL in the non-virtual field. I followed the answer ...
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0answers
86 views

Using GPS to field walk through a LiDAR scene

I am doing field surveying for archaeology using Lidar. If I attached a USB GPS to my laptop would it be possible to track where I am "in real time" on the Lidar as I am field walking? I'm wanting to ...
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0answers
29 views

Delineate new political boundary in dataset

In the political area I'm working on, there has been a recent formation of a new city, legitimized with government plebiscites and resolutions etc. Geographically speaking, it's still the same land ...
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2answers
312 views

Understand QGIS errors when importing .csv file

I am trying to import a .csv file as a layer in QGIS and keep getting a number of errors that I don't understand. Is there any documentation of QGIS errors available? Or can you point me towards a ...
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1answer
247 views

Cannot install “Processing” plugin on MacOS + QGIS 2.9.3, fresh install

I have just installed a new MacBook Pro and QGIS, everything is fine but this strange error if I try updating or reinstalling the "Processing" plugin. The plugin is broken. Python said: cannot ...
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1answer
92 views

Joining Parcel/Building Attributes Based on Coordinates

GIS noob here: I downloaded a building footprint shape file for a city and imported it as a vector layer in QGIS. I was hoping to see street address information in the attribute table, but there was ...
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0answers
125 views

How to make a model with more than 2 input layers for buffering and merging?

Would it be possible to add more inputs to Buffer and Merge? From what I can see there is a limit of two input layers per both. As far as I know this is possible in ArcGIS's Model Builder but from the ...
3
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1answer
147 views

How to change font color in one column of attribute table in Composer reports?

How do you change the font color in just one column of the attribute table included in QGIS's Composer? I would like to have the numbers listed in color red just for one column out of four columns in ...
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2answers
462 views

How to create a line between a point and nearest neighbour using python (template included)

I have 2 shapefiles - one is a series of points, the other is a polyline. I want to draw a straight line between each point to the nearest point on the polyline. This question has already been asked ...
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1answer
271 views

Adding point layer in QGIS from SQL Server failing

I just downloaded QGIS a few days ago (version 2.8.2-Wien) but I am not able to get it to work as I thought it would. I tried pulling in spatial data from sql server (a "geometry" column containing ...
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1answer
144 views

Problem with Memory storage type in PyQGIS when updating with auto form

I have a layer of "Memory storage" type (Memory provider) which I created with Python. When editing=on and updating values using the attribute table interactively everything works as expected, i.e. ...
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1answer
269 views

Combining multiple overlapping rasters - retain maximum value?

I have 40 overlapping raster grids (derived from flood modelling software) that I want to combine in such a way so as to retain only the maximum value in any of the given rasters at each grid location,...