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

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2
votes
1answer
67 views

How to create a 3D shapefile in QGIS?

How can I create a 3D shapefile containing line features or point features? I have to extract the elevations from a DEM and then export a shapefile containing 3D features. I'm currently working with ...
2
votes
1answer
32 views

Add layers to Spatialite Database using PyQGIS

I would like to add layers into a spatialite database. I have used the QgsVectorFileWriter method: parcDisSHP='/xxx/xxx/xxx/xxx/FILE.shp' parcelasDis = QgsVectorLayer(parcDisSHP, 'Parcelas_Unicas', "...
2
votes
1answer
59 views

Computing distance between two points following network and doing it for 100.000 points?

My starting data : a collection of points which are buildings a collection of points which are electrical transformation plant a network of vectors which is the public electric network from an ...
1
vote
1answer
55 views

In QGIS is there a way to make one polygon out of several

I'm trying to use QGIS to get a more simplified vector country data. For example Canada has several bits to the north all as separate polygons where as I'd be happy to just take a rough outline of the ...
1
vote
1answer
32 views

Why does Print composer draw wrong coordinates?

QGIS Version: 2.14.3 EPSG: 32630 (WGS 84 UTM Zone 30N) I´m trying to draw a grid with EPSG: 32630. Layers are in the same CRS. As you see, coordinates are completely off. It does not matter if I use ...
4
votes
1answer
66 views

How to selectively generate averaged raster layer from 5-year data raster layers in QGIS?

I would like to merge 5 years of world ocean surface productivity data raster into 1 averaged raster in QGIS. However, not every pixel has data in every year. To generate the raster layer with the ...
1
vote
0answers
27 views

Merging DEM file generted many negative value in QGIS

With four DEM files downloaded by Python Elevation package, I merged them in QGIS 2.8.3. I use raster-> Miscellanaous -> Input direction, no more attribute was added. The four dem data has ...
2
votes
3answers
230 views

How to use field calculator to change values from a,b,c etc. to 1,2,3 etc.?

I have a vector shp with a column with string values. How can I convert this to a column of integer values in another column but keep the categorization: e.g. from: col1,newcol2 A, A, B, A, C, to: ...
1
vote
0answers
48 views

How to calculate raster area or number of cells for multiple classes in a raster?

I have a raster with many classes and I want to know the area or the number of cells for each class. I found quite a few posts on this topic (see links below). None of the suggestions matched my ...
1
vote
0answers
20 views

Run and install packages from local folder QGIS [duplicate]

I use QGIS in my work and sometimes need install python libraries for plugins to work but I don't have write access to C:/ where QGIS and python is installed (OSGeo4W). Is there a way I can install ...
2
votes
0answers
28 views

Using “Difference” in Geoprocessing Tools results in Minidump

I want to use this tool on 2 vector layers but as soon as I start the process I get a minidump and I have to close QGIS. Does the .dmp file help you in solving this? Or can I open it and look for ...
2
votes
1answer
46 views

georeferencing swisstopo print

when i tried to georeference a printout from map.geo.admin.ch, either the result got turned some degrees, or the height got compressed or both. using the helmert transformation gave me the best ...
1
vote
0answers
35 views

Cutting many lines (as rivers) that are outside of a polygon in QGIS

I would like to extract only the vector lines, that represents rivers in my case, inside a polygon. I tried to use the intersection and clipping from QGIS, but couldn't do it. Any help?
2
votes
2answers
63 views

Mistake in Calculating Area or a Bug in QGIS? [duplicate]

I am trying to calculate the area of a polygon following the step by step mentioned in all the questions related to this issues in this website. Nonetheless, the result of the area calculation is ...
3
votes
1answer
63 views

Hillshades created from QGIS Virtual Raster Tables sometimes have unwanted artifacts

Using QGIS 2.14.3 I tested Virtual Raster Table technology for the first time using two TIF DEMS (NED 1/3 arc-second, projected to EPSG:3338, single band, 32-bit floating point, ~ 5-meter resolution). ...
3
votes
1answer
73 views

Start multiple processes with one action

I am trying to start multiple processes with a single action in QGIS. With Windows commands it is not hard, see here: http://stackoverflow.com/questions/13719174/how-to-execute-multiple-commands-in-...
1
vote
0answers
20 views

Upload a raster in postgis

I know this might be a similar question to many others. I have been prompting multiple questions here and on google but I cant figure it out. I have a raster and I have uploaded it into postgis with ...
1
vote
1answer
54 views

Visualizing interpolation result with three js in QGis

I used topographic map to trace the contours in QGIS. For each line, I added an attribute value (ex. 565, 564, 563 etc). After that, I used the IDW and TIN interpolation methods to create a couple of ...
4
votes
1answer
65 views

Stratified Random Sampling Tool

Is there a way to produce a certain amount of random points over different classes in a raster in QGIS? I have extensions such as GRASS or GDAL, ...
-1
votes
0answers
25 views

QGIS and image server

I am lacking in knowledge and wanting to link to the following image service. how do I get this link correct for QGIS ? http://gis.pcc.govt.nz/arcgis/rest/services/Base/Urban_Aerials_2016/...
2
votes
1answer
49 views

Plugin for fast export selected features from multiple layers

Is there any tool or plugin providing export of selected features from more than one layer on one click? I need to create multiple exports from three layers. Feature from layer one, then feature from ...
-3
votes
2answers
43 views

Finding address geographically? [duplicate]

Is there a way to make Geocode or location address based on a shapefile streets, without using a web service and using QGIS or some open source software?
2
votes
0answers
48 views

QGIS equivalent of Calculate Adjacent Fields for Atlas

Is there a QGIS plugin available or a processing model to calculate and populate fields that can be used to label the adjacent pages in a map book? Although there are tools to create vector grids, I ...
1
vote
0answers
21 views

Convert a SHP file set to a categorised ASC raster with Qgis?

I have a shapefile with regolith (soil) data that I would like to use as a categorised raster (say 007_1ASC) in Maxent. The regolith data is in the following files: 007_1.cpg 007_1.dbf 007_1.prj ...
1
vote
0answers
26 views

Classification of multiple values at the same point

If I have a point dataset with multiple values for the same geographic location (e.g. residuals from a regression where multiple individuals live at the same location) which I classify using quantile ...
2
votes
2answers
95 views

How do I get the building housenumber from OSM data?

I've made a map in which buildings in a city are displayed using shapefiles from Geofabrik and unfortunately, none of the shapes contain the housenumber. When I download the .osm files from Geofabrik ...
1
vote
1answer
35 views

Geoprocessing in CRS WGS84 and UTM Zone in QGIS

Why do I can't do union or do another geoprocessing two shapefiles with different CRS in QGIS? For example, I want to do union two shapefiles, one shp with CRS WGS84 and another shp with CRS WGS84/UTM ...
2
votes
1answer
63 views

Is there any plugin to Identity in QGIS? [duplicate]

Identity is one of ESRI ArcGIS Feature that clipping feature class by another feature class then union first feature class to the result of clip process. The simple explanation is like this picture ...
2
votes
0answers
42 views

Automatically split line at intersection of nearby shapes/zones

I have a large dataset in QGIS with roads (blue line in picture below) and 3 type of zones (mostly rectangular areas, red and green shape in picture below). My task is to spilt to road into segments ...
1
vote
2answers
82 views

how secure is data on qgis? [closed]

What is the safety guarantee using the QGIS platform for data storage? I want no data loss and easy access to data when stored. Can passwords be used to safeguard data and how do I give permissions to ...
3
votes
1answer
51 views

QGIS 2.14 Debian Sid - Couldn't load plugin 'processing'

The processing plugin can't load because python import error for QtWebKit.QWebView. QGIS is installed from Debian official repositories. The plugin worked fine until 2.14.1. The error message at ...
2
votes
0answers
38 views

Aligning layers in QGIS?

I am new at QGIS and am having a problem aligning layers. Possibly I just don't understand how projection works. I have 2 layers: 1) GPS waypoints collected in a GPS UTM zone 55N 2) polygon ...
4
votes
1answer
86 views

How to load multiple vector layers into QGIS' map canvas using python scripting?

I am trying to write a standalone script in python to create a QGIS map canvas. The vector layers I am attempting to load are Shapefiles. Currently, I am able to load each vector layer, add them to ...
1
vote
1answer
60 views

Counting nodes/vertices in large polyline GeoJSON?

I have a large .geojson file (~ 1 GB) of made up of thousands of polylines. My objective is to count the number of vertices (not end points) in the entire file. Is there a python module that is ...
3
votes
1answer
50 views

Create street map with A-10 type grid & index

I need to create a printed map using QGIS with an arbitrary grid superimposed, such as is usually found on street maps.. say A to K on one axis and 1 to 10 on the other. Then I will need to create an ...
1
vote
1answer
33 views

GRASS/QGIS- “buffer” created with DEM analysis- how to avoid it?

I have, to start, a DEM raster and a shapefile, with random created points, within a given polygon. The DEM raster was clipped with that same polygon. With the DEM raster, I used GRASS to perform ...
1
vote
2answers
59 views

Are there roadmap datasets available for qgis?

On ArcGIS.com, you can download public datasets such as road maps. Do these work with qgis or are there public datasets available for qgis? By public, I'm referring to datasets that others have ...
2
votes
0answers
19 views

get active colourramp form qgis rasterlayer

I m building a pythonscript were i need the active singleband pseudocolour colourband of a raster. I want to give the active colourramp a new min and max value. I can only find examples like this ...
0
votes
2answers
48 views

how to insert Co-ordinates (LAT. and LONG.) in a map composer of QGIS 2.8

In QGIS 2.8, how to insert co-ordinates (degree, minute and second) in map composer? when I did it, the the X and Y intervals value were showing on the frame instead of actual lat. & long of the ...
0
votes
0answers
26 views

Raster to categories to shapefiles

I have a raster data file which is the population density. I would like to transfer this raster into a specific number of categories, let's say 5. After that I would like to convert the raster to a ...
2
votes
0answers
21 views

classify colourramp with new min and max value with python

For my script i want to update the existing colourramp of a raster with new min and max value. In my current code is can fill the min and max but can't classify and update the raster. How does the ...
1
vote
1answer
50 views

How to delete one band from raster file?

I was working using drone imagery (regular camera) and there is this alpha band which is preventing me from doing maximum likelihood classification. I want to remove the alpha band. So far I used ...
1
vote
0answers
48 views

KML with raster in QGIS

I have a kml file which displays correctly in Google Earth but only as a bounding box in QGIS . What can I do to see the associated raster image?
3
votes
1answer
105 views

How to make some labels BOLD using Expression Builder QGIS

I am using QGIS 2.14 and I am trying to make some of my labels bold to stand out. I'm not sure how to do this using the expression builder. I know this is wrong and I was wondering if someone could ...
3
votes
1answer
33 views

QGIS geoprocessing script, ## hand-over processing-specific information error

I have a QGIS python geoprocessing script starting like this: ## Networking = group ## lIn = vector ## lOut = output vector from qgis.core import * v = processing.getObject(lIn) #[...the rest...] ...
1
vote
0answers
28 views

Problem in layer overlapping (qgis)

I want to plot gps pts on qgis (version 2.14.1). I have added the vector layer of SE Asian countries, and added the delimited text layer of my gps pts which included species name, lat and lon. ...
5
votes
1answer
125 views

QGIS display on high resolution screens

I recently changed over to a laptop with a 3200x1800 resolution screen, and QGIS no longer displays properly. Many items and font are too small and almost unreadable. Slight improvements can be made ...
3
votes
0answers
29 views

Rotate feature by angle (QGIS)

Trying to offset a line by 10 degrees, rotating around an endpoint. I've read up on the older plugins and the new Rotate Feature tool, but am having trouble. I am using QGIS 2.8.9 Wien, reinstalled ...
1
vote
2answers
53 views

Creating an artificial coordinate system to plot a garden experiment

I am trying to map plant death in a garden experiment. The location of the garden doesn't matter, I just care about each plant in relation to the others. They were all planted on a grid system. My ...
1
vote
1answer
30 views

QGIS- extract raster information into a point return nulls

I have a 1) raster layer and a 2) point layer. I want to extract the pixel value to each point, but it is not working when using this tools (QGIS): plug-in "Point sampling tool" (the new shapefile ...