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

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0
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1answer
38 views

Geotag shape files

I have several shapefiles that are supposed to be in epgs:4326 but the projection is correct only relative to each other, not absolutely. Is there a way I can geotag shapefiles without having a ...
2
votes
1answer
42 views

QGIS 2.14.3. positioning gap between open layers layer and aerial image

When I add aerial images from a recent survey (delivered in EPSG:31468, DHDN_3_Degree_Gauss_Zone_4) to an empty project together with an openlayers osm layer I'm facing a strange positioning issue. I ...
2
votes
0answers
35 views

How to keep basemap high res detail when printing large resolution in QGIS?

I need to print a map with a0 resolution and I need it zoomed over a large area. Problem when zooming out is that the basemap also gets zoomed out and loses labels and important details. Basemap is ...
2
votes
1answer
38 views

Rendering based on layer overlap qgis?

I'm a little new to this, is there a way to have features on a layer render only if they overlap with features on another layer? I have roads of a city, and different areas in the city, and I'd like ...
1
vote
1answer
23 views

Change project CRS = discard GCPs?

[Using QGIS 2.12 Lyon on Mac with OS X 10.10.5] I am struggling to georeference some old hydrographic survey maps that are in the form of TIFF files (.tif). If I open the georeferencer tool and set ...
0
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0answers
42 views

Read a vector layer from a Postgres/PostGIS database via a SQL query with QGIS and ogr in a python script

I have a treatment table for different aggregation stategies on a geospatial table in a PostgresSQL/PostGIS database. The aggregation strategies addressing temporal and species specific pre-selections ...
2
votes
2answers
48 views

qgis raster palette won't appear

I am trying to style a new single-band raster with a platted style, but when I choose the ‘platted’ no colors or values appear, and I can’t find a way to add them. QGIS Essen, Win 7.
2
votes
2answers
193 views

openlayer-plugin error after installing update

after installing an update for the openlayer-plugin today, this plugin does not work any longer. Reinstalling did not function neither with QGIS 2.12.0-Lyon nor with QGIS 2.14.1 ESSEN. Following error ...
1
vote
2answers
35 views

Integrating R in QGIS with Mac OS El Captain: missing dependencies

I have a Mac OS (El Captain) and I'm trying to run R scripts within QGIS 2.14. When I open a script (like one from the online list) I receive the error message: This algorithm cannot be run :-( ...
3
votes
2answers
78 views

How to organise complex styling rules in QGIS?

For example, my "roads" vector layer has the following attributes: road type: primary, secondary, local, track, or path surface: sealed, or unsealed segment type: road, bridge, tunnel, floodway, ...
2
votes
1answer
53 views

pyQGIS merging shapefiles

I've been searching the internet for a while now trying to look for a way to merge all the shape files from a directory (a folder) into a single shape file. I found many solutions but none of them ...
1
vote
0answers
57 views

Where does the snapshot command take its pixel samples from?

I'm using the snapshot command in QGIS with a horizontal extent from 0 units to 24 units to create an image with a horizontal resolution of 4 pixels. Are the output pixels located at 3,9,15,21 (...
1
vote
1answer
46 views

How to get neighbor list and export

I have a shapefile from the Census Bureau on Zip Code Tabulation Areas (http://www.census.gov/cgi-bin/geo/shapefiles/index.php). I wanted to get, for each zip code, the list of neighboring zip codes. ...
1
vote
1answer
50 views

Using 'ogr2ogr' algorithm in QGIS to transform SHP to GPX

So I am trying to convert a LineString shapefile into GPX using the 'gdalogr:ogr2ogr' algorithm in a QGIS python plugin. The problem is that I alway get routes instead of tracks, even if I specify ...
0
votes
2answers
46 views

QGIS autoupdate attributes

How to change attributes value when i move(change position) point? I don't found some information about this. Sorry for my english.
3
votes
2answers
171 views

Generating an image representing inland surface water using QGis and OSM data

I'm trying to generate a raster image representing surface water for a given bounding box. I'm using OpenStreetMaps data as my input for water bodies, and I'm using QGis on Ubuntu to process this data....
3
votes
0answers
45 views

Python QGIS crashes within categorized renderer setup

I'm hassling around with QGIS renderer definitions in python with QGIS 2.8 at debian wheezy. At least I want simply build step by step a categorized renderer to fill a polygon. The script crashes, ...
1
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0answers
27 views

How to create dissolved buffers using QGIS virtual layers?

To create dissolved buffers in PostGIS I use ST_Dump and ST_Union: SELECT row_number() over() AS gid, sbqry.* FROM ( SELECT (ST_Dump(ST_Union(ST_Buffer(input_layer.geom, 100))))....
4
votes
2answers
93 views

QGIS doesn't update some snapping options from Python

I've just installed QGIS 2.14.3 (Essen) on a Windows 7 machine, so I've got the default configuration on everything. This means that under "Settings -> Options -> Digitizing", I've got "Default snap ...
0
votes
0answers
22 views

Clipping and exporting raster from QGIS to Google Earth?

I have a 3 band raster from which I need to clip a portion, and then visualise it in google earth. The problem is that the file generated after clipping, shows OK in QGis, but looks completely black ...
1
vote
0answers
33 views

QGIS crashes when printing

I have a 50 MB shapefile. I am trying to import it into Illustrator. When I try printing to an svg file from the Print Composer, QGIS crashes. I am using QGIS Essen 2.14.3. I have tried lots of ...
2
votes
1answer
59 views

How to find near polygons

I have some polygons with attributes (in my case, some polygons have health establishments) and others without attributes (without health establishments). Is there a function that I can use in order ...
1
vote
1answer
26 views

Character problem when save map Atlas

I have 45 maps produced with Atlas. I would like to save them with their names. However, there are character in these names that windows doesn't accept in file name. So, I'm tring to do a expression ...
5
votes
1answer
140 views

Land Use classification and canopy cover using LT8 imagery and ground truth points in QGIS

I am trying to run a land use classification with QGIS on LANDSAT8 imagery to classify the various land uses within an area of northern Vietnam. I want to distinguish between primary forest, ...
1
vote
0answers
39 views

How to join a table based on postcodes in QGIS?

I have 2 datasets, a shapefile with postcode polygons and an excel table (.xls) with postcodes and building count. How to represent the excel table in the map? I know that in ArcGIS it's possible to ...
1
vote
2answers
39 views

Add a geometry in sqlite in pyqgis

I'm trying to create a geometry column in a table which I created. I found the following code: cur.execute('SELECT addgeometrycolumn(%s, %s, %s, %s, %s)' %(table_name, geometry_column_name, EPSGcode,...
3
votes
1answer
93 views

NDVI analysis of LANDSAT 8 imagery in QGIS

I am trying to run an NDVI classification of 2015 multispectral LT8 imagery in QGIS to assess the quality of vegetation cover in regards to habitat suitability for a primate species in northern ...
1
vote
0answers
9 views

Switch QGIS proxy settings programatically

I am using QGIS at two offices with different proxy-servers. At the moment I have to change the proxy settings manually every time i switch the office. I was wondering if its possible to change the ...
1
vote
1answer
38 views

QGIS virtual layer path never saved as relative

When I try to use virtual layers in QGIS, I'm unable to use relative paths. I've already set in the "Project Properties", in the tab "General", the "Save paths" as relative. You can see a ...
1
vote
0answers
35 views

Scroll for qgis custom form

I made form in qt designer for QGIS. But there are a lot of fields in It and It can't placed in screen. I want to add scroll area in my qt designer form but It doesn't work as scroll doesn't appear. ...
2
votes
0answers
21 views

How can I show photos in popup from a ByteA (postgis) in QGIS (or Google Earth/map)

I currently have a postgis database with a table containing point geometry of fire Hydrant. This table contains a raster_blob field which contains the Fire hydrant picture taken by field workers. ...
1
vote
1answer
33 views

How to Create a Catchment Area of a Polygon (Wetland) using DEM in QGIS or Whitebox GAT

I am looking for a way to calculate the upstream catchment area where water would flow into a given wetland. I have delineated the boundary of a wetland (creating a polygon) and would like to ...
2
votes
1answer
58 views

Add multiple rasters using QgsRasterLayer with for loop

I am trying to create a for loop for coloring up multiple rasters simultaneously. I am able to do it for one layer, but trying to implement the for loop to do it for more than one layer is proving ...
1
vote
1answer
26 views

Proportional circles as function of value NOT range

I have two point layers, each containing one column of values. When using the graduated style in layer properties, the size of the points is relative to the total range of values within that layer . ...
1
vote
0answers
23 views

grass algorithm changes integer to fixed length

using grass v.clean in the graphical modeller it changes all integer values from the original file to int with length 9 Is this a standard behaviour? Can this be avoided? The details of the grass ...
2
votes
1answer
26 views

If keep resolution = False in gdalogr:cliprasterbymasklayer

What does it mean if i put keep_resolution = False in gdalogr:cliprasterbymasklayer? In the tool itself in QGIS I could choose then a resolution which I want to have for the output, but here via ...
1
vote
0answers
27 views

Is there a Python equivalent to QGIS Raster Calculator's “file1.asc” AND “file2.asc”

I would like to script a calculation equivalent to QGIS Raster Calculator's "file1.asc" AND "file2.asc". I have 18 data raster files which I would like to do the equivalent of ADD to each of five ...
2
votes
0answers
33 views

Connecting QGIS 2.14.3 to SQL 2012 both on LocalHost or Remote

I am working on establishing MSSQL (2012) spatial connection from my QGIS 2.14.3, its giving me an error like: (Error opening connection: [Microsoft][SQL Server Native Client 11.0]Named Pipes ...
2
votes
3answers
110 views

No Module named qgis

I installed QGIS through OSGeo4W, and I am trying to write a standalone PyQGIS script, however, I am unable to import the qgis, qgis.core, processing ect… modules, as shown in the picture, I get the ‘...
7
votes
1answer
115 views

SVG markers made in InkScape appear transparent in QGIS

Using QGIS 2.14.3 on Ubuntu 16.04, I created a custom icon using inkscape for QGIS. You can find it here (Update: that icon is now fixed). In inkscape, in my filesystem, it displays as: However in ...
2
votes
1answer
36 views

Polygon intersection using QGIS virtual layers

I'm trying to intersect polygon geometries in QGIS by using a virtual layer: SELECT sbqry.rowid AS gid, sbqry.geom FROM (SELECT ST_Intersection(land_parcels.geometry, flood_zone....
1
vote
1answer
43 views

Split multiple attributes from a big polygon to smaller ones

I am looking for a sort of spatial (un)join function. Let's say I have 2 tables, both with a large number of polygons. The first one has a pop/polygon column in his attribute table. The 2nd one has ...
1
vote
0answers
21 views

How can I stop crashes when opening layer properties after adding SVG paths?

I am running the most recent version of QGIS, 2.14.3. I recently added several folders to the locations of of SVG files, but I opened the Style Manager and removed them when the crashes started. ...
1
vote
0answers
28 views

Compressing clipped raster in QGIS?

I am using QGIS: Raster/Extraction/Clipper I have a raster image (Sentinel 2 satellite 3 bands combination, total area: 1,000,000 hectares, file size 740 MB) from which I clip a certain area, which ...
0
votes
0answers
30 views

QGIS 2.14.3 very slow when saving edits on Ubuntu 16.04

QGIS 2.14.3 "Essen" is really very slow when saving edits on a single layer (point features) on Ubuntu 16.04 64 bits. There is only about 100 points in this layer. In editing mode, when saving, it ...
2
votes
1answer
47 views

QGIS geoprocessing scripts, default values for field names

In QGIS geoprocessing scripts, default values must be provided for input numbers and strings, according to http://docs.qgis.org/2.8/en/docs/user_manual/processing/console.html#creating-scripts-and-...
3
votes
2answers
45 views

Why do certain fields import as strings in QGIS?

I have imported a CSV to QGIS with lat/lon values representing points. The other fields, at least in the original CSV file, contain numeric values. > sapply(pune_hotspots, class) id ...
1
vote
1answer
55 views

How to load html file with leaflet map using PyQGIS

I have simple .html file with leaflet map layers. I want to load these layers in QGIS mapCanvas with ability to choose one of the layers. How can I load this .html and show one of map layer with using ...
2
votes
0answers
32 views

Dynamic Label or Annotation in QGIS canvas

I'm creating an animation from several Raster images, and I'd like to add a label or an annotation to the map canvas, not the print composer, that will enable me to show the layer's name, which holds ...
1
vote
0answers
13 views

How to write CRS info from QGSVectorLayer

I'm writing a plugin which will create a new virtual layer containing points. I know the CRS of the new layer, as it is the same as the layer I am using for input. I would like to specify the CRS in ...