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

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2
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1answer
29 views

Mapping out 3D points with QGIS2threejs

I have some points I would like to map out in 3D. The points were gotten from a GPS module athat was attached to a Raspberry Pi. This is the settings I used before starting qgis2threejs: This was ...
1
vote
1answer
31 views

Changing CRS in QGIS due to pop up window: "CRS warning! Warning: Input layers have non-matching CRS. This may cause unexpected results.” [duplicate]

I'm using GIS to map the movement of animals and their speed and density in different habitat types using shape polygons. When I got to the step ;Count points in polygon' a pop up window appeared ...
3
votes
1answer
41 views

Find out if overlaying polyline matches polygon centerline in qgis

I have a polygon and a polyline and I need to find a scientific way of how close that polyline is to the actual polygon centerline. Is there any way of doing this in qgis? Any extensions, models, ...
1
vote
0answers
39 views

QGIS LYON desktop cannot be opened on windows 7

I have installed QGIS lyon from http://qgis.org/downloads/QGIS-OSGeo4W-2.12.3-1-Setup-x86_64.exe on win7. I did not install the default data set. On my desktop, there are some icons of QGIS. ...
2
votes
1answer
36 views

Extracting NDVI using QGIS from multiple images to Excel?

I created 25 images in QGIS. Each image has different information about the NDVI of the area. How can I extract mean, max, and min information about the NDVI from each image and put it in Excel?
1
vote
2answers
38 views

How to eliminate points by difference (vector geo processing tool)?

I have a point that falls outside the bounds of my area of study. What I did was select it and resorted to vector commands - GIS - difference. Unfortunately I can not get the desired result. My ...
3
votes
2answers
72 views

Changing pixel size in 'asc' file using Qgis?

I have soil data and BioClim data from Australia soil data: rows 2200 columns 1400 pixel size 0.0025, -0.0025 255 BioClim data: rows 660 columsn 420 pixel size 0.00833333, -0.00833333 I am ...
1
vote
2answers
38 views

How to combine two polyline shapefile together

Here is my question Two shapefile: * A: represent the outer boundary of the city area * B: represent the inner boundaries of the city divisions. I want to * Combine these two shapefile * ...
4
votes
0answers
41 views

OS terrain 50: .vrt from zip files

I tried to follow what was suggested in How to use OS Terrain 50 in QGIS, but I got the following problem: in spite of being generally able to generate .vrt files using gdalbuildvrt from unzipped ...
1
vote
2answers
48 views

Calculate Z Median from 3d line?

How does one calculate the median value of Z from a 3D line? The Add Surface Information tool in 3D Analyst only does Min,Max and Mean (average), and requires a surface model. (In this case I have ...
2
votes
1answer
40 views

Automated clearing /tmp using QGIS batch processing?

I'm currently batch processing a bunch (~200 x 200MB) of ascii grid surfaces using some SAGA and GDAL algorithms in QGIS and have been running into "out of storage" errors. The issue is that between ...
3
votes
1answer
62 views

Counting polygons in one layer that are overlapping/touching/contained in each polygon in separate layer of contiguous polygons using QGIS?

I have a layer of contiguous (pink) polygons (UK Parliamentary constitutencies) and a separate layer containing (blue) polygons representing protected nature areas (Natura 2000 areas): Each ...
3
votes
1answer
26 views

Disable QGis Tips Panel when application start

I am trying to disable the QGIS Tips Panel with config files. I use QGIS Lyon. - QGIS2.ini - And a custom file define with the parameter --customizationfile I know the user can click on "I've had ...
2
votes
0answers
11 views

Qgis PCA plugin not responding

I am trying to do principle component analysis, my file size is 1,5GB. It has been not responding past 30 mins, but I decided not to close the program, is it running or I am just waiting for nothing? ...
2
votes
1answer
37 views

Rename cells in Attribute Table to 'XXX.$ID'

I feel like this should be easy to answer, but I can't get it to work for me. I need to edit the attribute table of a .gpx file before I load it into my GPS, in order to label the points. I can rename ...
3
votes
3answers
26 views

Connecting points - plugin problem QGIS

I have a question related to connecting points in QGIS. I am doing a project relating to transport. I have a layer of points (bus stops) and I have to connect them according to a timetable (as runs a ...
1
vote
0answers
44 views

Riparian corridor delineation in QGIS

I am trying to delineate the riparian corridors using GRASS in R. But I am having some issues. So is there a plugin in QGIS using which I can extract riparian corridors using the already available ...
1
vote
1answer
39 views

Decompose the polygon with polyline inside

Here is my question: I have a polygon shapefile represent the whole country area. A polyline shapefile(with a bunch of line boundaries) represent the province boundaries So, how to decompose the ...
3
votes
3answers
69 views

Can't replace attribute with field calculator

I have an attribute table where one of the columns (laeskaerm) has been edited/created by checkboxes on 2 different machines. Result: it contains both 1, 0, true, false and NULL I'd like to replace ...
3
votes
2answers
46 views

How to detect a covered polygon by other polygon in same QGIS layer?

QGIS - Identify overlapping polygons in single layer As described this question there are 3 conditions for two polygon on a same layer. These 2 polygons can have intersection area. (How to ...
3
votes
1answer
25 views

Advanced Digitizing Panel bad value or bug?

This is my first post here. What would cause the "Advanced digitizing panel" D (length) to show up wrong? I'm in the US using WGS 84 as CRS. If I add a feature (line) Advanced Digitizing Panels ...
3
votes
2answers
35 views

Adding Excel file with degrees to map with CRS in QGIS?

How can I add a layer with X,Y in degrees (from an excelfile) to a map with CRS? I am using QGIS 2.8.2
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0answers
24 views

python handling case in address (lowercase,uppercase) [closed]

I'm working on a python QGIS plugin that takes address info from specific parcels and lists it. The data is in various cases and I'm having a hard time figuring out how to handle it. My data looks ...
5
votes
1answer
94 views

How to use ST_Difference to create linestrings from non-intersecting polygon boundaries?

There are two tables with polygon features in my PostgreSQL database. I want to create linestring features where the boundries of the polygons are not intersecting. CREATE TABLE schema.poly_a ( gid ...
1
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0answers
22 views

QGIS crashes when using PostgreSQL/PostGIS triggers

When using PostgreSQL/PostGIS triggers saving layer edits gets slower and slower every time when saving a layer edit. This issue occurs after a few up to a few dozen saved layer edits. Finally QGIS ...
1
vote
1answer
39 views

When using the QGIS2web plugin (OpenLayers3 option), no HTML file is created

I'm using the Qgis2web plugin (the OpenLayers3 option), and there is no html file that is created. The folders appear (Layers, Styles, and Resources). My web browser opens when the folders are ...
1
vote
1answer
77 views

How to check the encoding in the .dbf files?

I am having difficulties when I try to load a shapefile into my database, the is because I do not know the encoding of the dbf portion of the shapefile. The attribute tables are in Spanish, I have ...
1
vote
2answers
33 views

How to compute the distance from the current polygon centroid to another in QGIS field calculator?

There is layer with polygons. I want to save in new field distance of every polygon's centroid to centroid of one particular polygon. To do this I should write some expression like this: ...
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vote
0answers
17 views

How to define the similar elevation points from 2 layers in the 4 nearests points?

I´m using QGIS 2.8.3. and I want to know what is the most similar elevation points value from a layer A to layer B in the 4 nearest points. My layers have an attribute table with Long, Lat coordinates ...
1
vote
0answers
28 views

QPyNullVariant not recognized outside of QGIS

So here is a weird one. I'm getting an error about an operation involving a QPyNullVariant: TypeError: unsupported operand type(s) for *: 'QPyNullVariant' and 'float' So I wanted to put a check ...
2
votes
1answer
76 views

How to compute zonal statistics fast?

I have 12000 circles with a radius of 50 miles on a raster with 0.05 degree resolution. Global analysis. The raster is 32 bit float and I have to calculate zonal statistics for 20 different rasters. ...
1
vote
1answer
16 views

Is there more than one option to change QGIS' temporary folder?

I have tried changing the TEMP folder of QGIS following this post,and although it wasnt required, I restarted the system after making the change, but still got no result (printscreen below). Is there ...
1
vote
0answers
13 views

How do I generate a sampling path by numbering points?

I need to number points from left to right and then the next row of points the numbering must continue from right to left, then again from left to right the row thereafter - and so on, and so on. ...
7
votes
4answers
164 views

How to compute max and min coordinates for multiple polygons?

I would like to calculate the maximum, median and minimum latidudinal coordinates for a large set of polygons, using QGIS or R. So the highest and lowest points reached by each polygon across a ...
2
votes
0answers
13 views

“Problem loading output layers” error when running algorithms on rasters in QGIS

I am trying to delineate a catchment from SRTM 1arc second data in QGIS. For this, I first try to use the Fill Sinks algorithm and then the Catchment Area algorithm. Both of the operations gives a ...
5
votes
3answers
166 views

Are there any portable versions of QGIS?

I am looking for a portable version of QGIS. Do you know if there are any portable version of QGIS?
3
votes
1answer
73 views

PyQGIS couldn't import processing with standalone script

I have read post on that problem (How can I access `processing` with Python?). The problem is even with a sys.path.append it couldn't import processing. It's very frustrated. Here the code I used: ...
5
votes
2answers
77 views

Label only the largest polygon of a multi-part polygon layer in QGIS

I am exploring the new Label engine of QGIS 2.12.2 and I found it a great improvement. However, I discover it is not yet up to ArcGIS "standard" when dealing with multipart polygons. As a workaround ...
2
votes
0answers
34 views

Extract coordinates of corner cells of a shape file in python script (QGIS)?

I have a grid in a Lambert Conformal Conic projection (with columns: ID, value) and I want to extract the corners of each cell in the native projection of the grid with QGIS. In particular, I want the ...
2
votes
0answers
25 views

Performing Grouping Analysis in QGIS? [duplicate]

Is there a QGIS tool that does the function of http://pro.arcgis.com/en/pro-app/tool-reference/spatial-statistics/grouping-analysis.htm MY NEED - I have about 15,000 points. I need them clustered in ...
2
votes
0answers
33 views

Why does QGIS Browser 2.12.1 keep freezing/crashing when I try to view a csv data table?

I've just downloaded QGIS Lyon 2.12.1. The desktop application works great but the browser crashes whenever I try to view a csv data table. I've gotten it to work once out of ten tries. I click on ...
1
vote
1answer
38 views

How to edit virtual field definitions in QGIS?

I have a virtual field in QGIS. The values are updates depending another column with a concatenate CASE statements. I would like to edit this statement but I cannot see it. I have attempted to use ...
1
vote
0answers
28 views

Same CRS but different units of raster cells in qgis

I have two rasters with the same CRS (WGS 84/UTM 34N). One is from a LiDAR scan and the other raster is created thru interpolation of point measurements by me. I would like to change the cell size to ...
1
vote
0answers
41 views

Arrows with direction and proportional to attribute

my data looks like this: > main end.station start.staion Freq end.latitude end.longitude end.station 1 359 519 929 40.75510 -73.97499 E 47 St &\nPark Av 2 ...
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0answers
20 views

Use QgsRasterCalculator inside function

I'm relatively new to PyQGIS and I'm building a plugin to perform some calculations between raster layers. I was seeking to use the QgsRasterCalculator for some operations, however, the function that ...
1
vote
1answer
24 views

How can I add r.local.relief to the QGIS Processing Toolbox?

I'm working with QGIS 2.12 and GRASS 7.0.3RC1. I'm making a model using the model builder and trying to add the GRASS addon "r.local.relief" in my QGIS model, but the addon does not show up in the ...
3
votes
1answer
21 views

'Fix' offset and undersized data in QGIS

I'm currently working on a project to visualize some climate data, among the datasets I'm using is the data from the NCEP/NCAR Reanalysis Project. Now, this data comes in a regular (non-gaussian) ...
0
votes
0answers
15 views

Processing toolbox on Google Cloud compute engine

I used to utilize the QGIS python console to do GIS batch operations on my local machine. Computation times are rapidly increasing and I'm switching to a virtual machine solution in the cloud. How ...
1
vote
0answers
27 views

Create GRASS Mapset in QGIS 2.12

How do you create a new GRASS mapset in QGIS 2.12? The GRASS panel has only the Open GRASS Tools button.I don't see any way to actually create a GRASS mapset in QGIS.
2
votes
1answer
27 views

PyQGIS: Change attribute value doesn't work, results in NULL

I am writing a QGIS plugin, which at one point attempts to change several attribute values on a layer. However, in the end no changes are made. If I punch similar code into the built-in Python ...