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

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5
votes
1answer
74 views

Keep UI Settings for a QGIS plugin

I'm writing a plugin that interacts with external software (hydrological models). One of the dialogs has a lot of entries (parameters to pass to the hydrological software). Once the user has set up ...
1
vote
1answer
14 views

TrainImagesClassifier (SVM) fails when executed from within QGIS modeler

I made a small model in QGIS that runs Second Order Image Statistics, the SVM Trainer, and Image Classification, all tools from the Orfeo provider. The problem is it fails everytime. When I run the ...
0
votes
0answers
20 views

Mini Dump to C when Printing

I'm aware that there have been many questions posted about mini dump issue, but I'm not particularly computer literate and some of it to be honest has gone over my head. Every time I go to print to ...
1
vote
1answer
35 views

Question about Using r.mapcalculator in Python console

According to the following conversation: Using r.mapcalculator in Python console? I tried: ##NoData Background=name ##RASTERLAYER_BAND=raster ##nodatabackground=output raster import processing ext ...
1
vote
0answers
17 views

Defining 3 decimals for value in layer properties of QGIS?

I'm currently working on the latest version of QGIS (windows) and I'd like to define a range of 3 decimals value when I'm editing the widget of my layer properties (column set as decimal number ...
2
votes
1answer
47 views

QGIS, how to export GeoTiff in lat long not map units?

I'm trying to export a map as raster (geo tiff with word file) from print composer. The word file is always coming with Map units because I'm using Google Satellite from OpenLayer web plugin. I tried ...
3
votes
2answers
50 views

Distance Matrix of two datasets

I have two datasets of the same adresses, one geocoded with Google, the other with Nominatim. Now I want to compare address1 of dataset1 with address1 of dataset2, then address2 of dataset2 with ...
2
votes
1answer
80 views

AutoCAD Map 3D GeoTIFF in the wrong place

I recently was looking at a way of using GeoTIFF in AutoCAD 2015. I was looking at a way of specifying coordinate system using one of UTM projections. I didn't have much luck with that and I decided ...
1
vote
1answer
49 views

Lines from points in postgresql postgis

I have this table (all row aren't in order): time, id, latitude, longitude time is character varying and the format is: dd/mm/year hh:mm id, latitude and longitude are numeric I would create lines ...
5
votes
2answers
144 views

Qgis: style a discrete raster

I have rasters with discrete values (Landuse categories, boolean values...). I would like to be able to style them in a discrete way: 0 -> Red 1 -> Blue 2 -> Green ... I wish something ...
1
vote
1answer
53 views

Use Only First “x” Characters from Table in qgis:selectbyexpression

I have a list of street names in this format: STRNAME Elsinore Neil Young Penny Fall And a shapefile ("input_streets") with street names in this format: STREET Elsinore Av Neil Young St Penny Lane ...
0
votes
0answers
34 views

Extract from DEM base on range of values in ArcGIS or QGIS

I have a very large 0.5-meter DEM and would like to extract a specific region of elevation values... e.g. I've tried creating a contour map but that was taking way too long- >24 hours.
0
votes
0answers
26 views

Polyline turned upside down and sideway (from encoded polyline to geojson to shapefile)

I was given an encoded polyline that I decoded and exported into a geojson file using the fabulous tool here: http://barryrowlingson.github.io/polyline-to-geojson/ but now I am running into another ...
1
vote
0answers
21 views

QGIS - convert multiple polygons to evenly spaced points within polygon boundary

I need to convert the polygons in a vector layer to evenly spaced points within the polygon boundaries in QGIS. The vector file contains >1000 polygons mostly with overlaps. The attribute data of ...
2
votes
1answer
43 views

I am trying to download QGIS Essen

I am trying to download QGIS Essen. I run the application and it says it has installed the program but it hasn't. I am using windows 7 and have previously downloaded QGIS successfully on another ...
2
votes
1answer
33 views

Failed DEM via Natural Neighbor in QGIS 2.14.2-Essen

Following the indications of Monde Geospatial (https://www.youtube.com/watch?v=bLbY3iMBW-A) I created a CSV file with the altitudinal data (Google Earth) for 2182 total points and imported it into ...
3
votes
1answer
76 views

Script that runs automatically from the QGIS Python Console when QGIS starts, using schedule tasks on Windows 10

I'm working with QGIS 2.8 and windows 10. Is it possible that after open QGIS using the schedule tasks from windows 10, I could open the python console and run a script within QGIS programmatically. ...
3
votes
1answer
33 views

QGIS Reprojecting a layer CRS

I have a series of layers of lines (shapefiles) in My Project. The CRS of some are different and to merge them they all must have same CRS. When I use ...
0
votes
0answers
33 views

Generating polygons from lines and problem with rings

I have a problem when generating polygons from lines. I got dxf file with layers: cadastral parcels (as polygons) soil classes (as lines) Now I want to generate polygons for soil classes (so I ...
1
vote
0answers
25 views

'Find Nearest' Equivalent in QGIS?

I'm a new user to QGIS, trying to solve a problem that I've encountered in ArcGIS Online. I want to run a 'Find Nearest' analysis, however the number of points I'm routing from is greater than 1,000. ...
2
votes
1answer
56 views

Displaying data from a partitioned PostgreSQL / PostGIS table is unacceptably slow in QGIS

I have two very similar datasets of 27 million polygons stored in PostgreSQL / PostGIS. One is loaded as a single table, with spatial indexes and regular indexes on key fields. The other is ...
3
votes
0answers
45 views

How to access attributes from linked tables (QGIS 2.14.2 Essen)

I have one source shape file like this: It consist the geographical coordinates of weather stations: And several attribute files, wich contain the Temperature data of each date for several years ...
2
votes
1answer
35 views

Using labels with diagrams in QGIS?

I'm trying to display point data as diagrams with labes next them. I'm getting the diagrams and labels to work separately, but they won't work together. When both are turned on, the labels disappear ...
1
vote
0answers
28 views

Installing QGIS on Mac OS X?

After failing to successfully install QGIS 2.14.2 Essen on my Mac OS X 10.7.5 (Lion) I thought I could try a previous version of QGIS. What download file should I use from the QGIS "all releases" ...
2
votes
1answer
28 views

How to set zero value of reflectance number of land using QGIS?

I try to get SST (Sea Surface Temperature) data from Landsat image using QGIS, but I don't know how to set zero value of reflectance in land area using QGIS. Does anyone know of any method to set ...
2
votes
1answer
33 views

Line density map in QGIS

I would like create something like that in QGIS: http://2.bp.blogspot.com/--EFSaghZ92s/VqQXXIoE4AI/AAAAAAAABKw/KGkoB8zZ6K8/s640/scs2%2Bmap.jpg I have a huge amount of points and I can import in QGIS ...
3
votes
1answer
64 views

Select by expression and remove points

How do I select points by expression and delete these selected points? Is it possible to do this inside the modeler with a tool? The selection by expression works fine but do I have to set all the ...
1
vote
0answers
19 views

Making two maps the same

I am producing radar maps from the NEXRAD site near Omaha (OAX) using GrADS. I'd like to make a basemap in QGIS. I put a geotiff version of the GrADS output in QGIS and had it 'zoom to layer.' In ...
4
votes
0answers
28 views

Using QgsNewVectorLayerDialog

I am using QgsNewVectorLayerDialog for taking user input for creating a new shape file. When the user clicks OK i am reading the inputs selected by the user using the following code. dlg = ...
1
vote
2answers
51 views

Decode encoded polylines to usable format for QGIS

Beginner alert. I was given a set of encoded polylines that I need to import into a QGIS project. I understand what encoded polylines are but now I am stuck with how to decode them into some usable ...
1
vote
0answers
32 views

GRASS gis: treating certain cells as starting points in mapcalc

I am attempting to calculate the vertical height from horizontal of every point on a slope. I want to use stream beds (the lowest points in my DEM) as my starting spot, with the horizontal plane ...
1
vote
0answers
12 views

Append object from another layer to the new layer through form (drop-down list)

I'm trying to get to know is it possible to append object from another layer to the new layer through form (drop-down list)? Do I need to create an application? If yes please tell me what language ...
3
votes
1answer
76 views

Same crs, different spatial reference system units, shape files / QGIS

I have two files, same crs but different reference system units and different scale. Long story short, the shp files won't overlap :( I've read some answers to what seems to be the same problem but I ...
3
votes
1answer
39 views

GRASS r.reclass QGIS 2.14. error: “the following layers were not correctly generated”

I am getting a strange error message when running the GRASS r.reclass algorithm. The error states that: "The following layers were not correctly generated *reclassified You can check the ...
2
votes
0answers
36 views

Fit images to polygons

I have a vector map with all the zip-codes of Denmark. I have taken a picture in each zip-code, and I now want to fit theses pictures into the zip-code polygons (I'm using QGIS). I can add the ...
1
vote
1answer
34 views

QGIS - Get Bounding Box of Map Extent in Stand Alone Application

I basically have the same question as this one : How to quickly calculate bounding box coordinates of a selected polygon with qgis However I am building a stand alone application in python and so ...
1
vote
0answers
28 views

shortest path layer display

i'm working to find the shortest path in mapserver apllication after i created my layers which are 3 ( base layer , edge layer and node layer) i created my mapfile and the tree.js file ( javascript) ...
0
votes
0answers
10 views

shortest path in mapserver application [duplicate]

i'm working in application of shortest path using qgis 2.12 and mapserver i created the mapfile and tree.js file ( javascript) and the php code and i created the database using postgresql`entfunction ...
4
votes
1answer
29 views

Filter a range number in Query Builder of QGIS 2.8.6

I need to filter features that have attributes that start within a relative number range. I am using brackets to filter the range of numbers, but it does not work me. This is my query: CASE WHEN ...
3
votes
1answer
74 views

Removing cloud from Sentinel 2A imagery?

I would like to use sentinel 2A imagery to look at canopy cover in Northern Vietnam. The only problem is that ALL the recent images have large amounts of cloud in the area I want to look at. Is it ...
1
vote
0answers
19 views

Using angle attribute to split voronoi polygan to three small polygon in QGIS?

I have a point data set, that include [id] and [angle] attribute, like 0/120/240。I made voronoi layer use point, i want to use angle attribute split voronoi polygan to three small polygan, how to do ...
1
vote
0answers
27 views

Grid interpolation using a new calculated field

Still learning.... I am trying to run the grid interpolation tool on a point shp file. I can successfully use the tool with the existing data but cannot run the tool on a new field I created in the ...
2
votes
0answers
30 views

Data is lost after merging selected features and pressing save

I've run into this problem multiple times. I'll merge features and the data will appear. Then when I hit the save button, all my merged data are replaced with null. This is in QGIS 2.14.1
3
votes
1answer
42 views

Create an Origin - Destination map using roadnetwork layer

I am using Qgis 2.14.2, I am trying to create a O-D using the road network that I have in a feature. Is any way or plugin that can help me to plot 500 trips using as a path my road network layer? I ...
1
vote
0answers
34 views

Populating label fields in print composer

Is it possible to fill text fields in a print composer template using data saved in a csv file? For example, every template I create has the same fields which I always have to manually enter: Client ...
1
vote
0answers
37 views

how to while true in thread for qgis plugin?

I am currently working on qgis plugin that searches for information every 5 seconds from database and refreshes the map. In my first version, I used Qtimer to do this job. However, in my second ...
2
votes
1answer
57 views

Postcode mapping (QGIS): how to transform OS csv data to an polygon map (.shp)?

I am trying to obtain a full England postcode map (polygons) out of free (and reliable) data out there. The English National Office of Statistics does share a huge list of postcodes and some ...
0
votes
0answers
48 views

Why does ST_Area in SQL give a different value to $area in QGIS?

The area value I'm getting using the SQL term 'ST_Area' is markedly different from that gained from QGIS functions like $area, the area measure tool and area as a derived feature (all of which agree ...
1
vote
0answers
17 views

QGIS-I have 37 polygons, can I bulk create 2 other sets of 37 that are 1 px larger all the way round and 1px smaller

I have 37 polygons covering a Lakes spatial extent at a particular point in time. I need to bulk create 2 sets of polygons. One 1 px larger all the way around and one 1px smaller to calculate the area ...
3
votes
3answers
53 views

How to add all “.dat” files (raster) into QGIS, in a defined directory and defined legend (style), using python code

I'm using a QGIS 2.8.3 in Windows 10. I've added just one raster ("dat" file) to the QGIS, with a defined legend, using the following code. If I wanted to add all the "dat" files into a directory how ...