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

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4
votes
4answers
2k views

How to sum raster image values with vector overlay

I'm new to this and haven't been able to figure out how to do this on my own. I have two files: a raster image of land use data and a vector-based shapefile of my territories. The raster image has ...
3
votes
0answers
148 views

Snapshot command not producing high-res image

I'm trying to export an image of my project with a size of several hundred megapixels (32768x16384) via the snapshot command and all I get is an output file with 0 KB and no error message. I can ...
0
votes
0answers
6 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 ...
0
votes
0answers
6 views

Qgis can not read to geometry type(point,line,polygon)in esri geodatabase *.mdb? [on hold]

Qgis can not read geometry type on ms access*.mdb's table connecting with esri personal geodatabase *.mdb? This can open as test file, but unknow geometry type. how to add long/lati format on *.mdb ...
0
votes
0answers
7 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. ...
0
votes
0answers
5 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. ...
0
votes
0answers
4 views

How to update water levels through Midvatten plugin for QGIS

I am using the Midvatten plugin for ArcGIS to plot water levels on a time series graph. I need to update my water levels, but the import water levels does not work for this because the water levels ...
0
votes
0answers
10 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 ...
0
votes
0answers
11 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 ...
1
vote
0answers
33 views

How to remove, using script, non present entry inside legend symbology?

Using Qgis after loading shp file i loaded a general qml files that are coded for a specific field for my shp. Inside qml are coded a larger number of symbology of the field that not all are present ...
6
votes
2answers
3k views

Error message: qgis_core.dll missing

I have a fresh install of QGIS 2.4. When trying to open a .shp file I get the error message below. I've followed their advice and have done several re-installs and also cleared all qgis files from my ...
0
votes
0answers
15 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
31 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 ...
2
votes
1answer
67 views

Create Layer With Selected in QGIS

Came across this "Create layer with selected" button in the result for a Spatial Query in QGIS. And simply, this creates another layer from the same source with a query on the IDs. Does anyone know if ...
2
votes
1answer
543 views

How Can i create a Vector layer from selected features qgis

In my qgis plugin i select dynamically features from a Vector layer. and currently i create a new layer from selection on combining all feature into a new feature: theField = QgsField self.theString =...
0
votes
0answers
47 views

how to create geometry type(point,line,polygon)on esri personal geodatabase*.mdb?

Qgis can not read geometry type on ms access*.mdb's table connecting with esri personal geodatabase *.mdb? This can open as test file, but unknow geometry type. Point can create using with "point ...
4
votes
1answer
73 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 ...
0
votes
1answer
20 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 . ...
2
votes
3answers
71 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 ‘...
1
vote
0answers
6 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 ...
6
votes
2answers
2k views

How to completely uninstall and remove QGIS 2.8.1?

I want to uninstall and completely remove QGIS installation from my computer(windows vista). I have uninstalled it and when i try to reinstall it says it is already installed on the system.
2
votes
1answer
54 views

How to set “draw line inside polygon” using Python?

In the QGIS properties of a layer I want to activate "draw line only inside polygon" for a specific layer, but using Python. I don't want to use the GUI for it. Can this be done? I set the line ...
0
votes
0answers
20 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
14 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
0answers
626 views

No tables listed in connection to MSSQL 2012 in QGIS

I've (finally) made a connection to my MSSQL 2012 database, but no tables are listed. Here's the tree view of the connection, and the connection properties: Some notes and questions: I've read ...
1
vote
1answer
278 views

Can't get my QGIS external map to display on Ubuntu trusty: QObject::connect: Cannot connect (null) error

I've been following along the examples from the book "Building Mapping Applications with QGIS and for the life of me I can't figure out why my shape files aren't loading and displaying in the app ...
3
votes
7answers
2k views

Can QGIS export Geospatial PDF for Avenza PDF map app?

Since QGIS uses GDAL, does any map exported as a PDF become a Geospatial PDF? I am hoping to import maps from QGIS into the Avenza PDF Map app on my phone. Previous posts mentioned exporting as ...
1
vote
0answers
22 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 ...
3
votes
1answer
73 views

QGIS MSSQL Spatial Layer Instant Crash

I am able to connect to the mssql server database and choose the table that contains the spatial data. However, as soon as the layer is added, I get the 'crash dumped' error with a message saying "...
13
votes
0answers
7k views

Is it possible to export geospatial PDF from QGIS via GDAL/OGR? [duplicate]

Is there any plugin for QGIS which would help me in exporting the map document as a geospatial PDF (similar to Terrago's GeoPDF)?
2
votes
1answer
26 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....
3
votes
1answer
67 views

Qgis slow on loading project

Is there any work around to mitigate the amount of time QGIS takes when loading projects that have large tables from postgis layers . I have tried to turn off this large layers so they are not in use ,...
1
vote
1answer
686 views

How to add the current project path in Print Composer?

I'm trying to demonstrate to my company that we can begin using QGIS in conjunction with (and sometimes even instead of) ArcGIS and MapInfo. I've started setting up some layout templates but have run ...
1
vote
1answer
18 views

How to create a label with QGIS project path in print composer? [duplicate]

Is there a way in the Print Composer of QGIS to create a label that will automatically update the path of the QGIS project?
1
vote
0answers
15 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
1answer
30 views

How can I export single bands of a MODIS image with QGIS?

How can I export single bands of a MODIS image (in particular MODIS Terra - MOD02HKM) with QGIS? It's .hdf file but with QGIS, I don't know to export these. I also used Modis Reprojection tool but ...
-4
votes
0answers
24 views

How to make a layer with a cone y QGIS? [on hold]

Is there any plugin for QGIS to do this ?
-3
votes
0answers
30 views

Incremental (dynamic) Delaunay Triangulation

Is there an incremental (dynamic) Delaunay triangulation in QGIS or using a plugin ? While the “batch” construction of the Delaunay triangulation of a set of data points, for example, is well known, ...
3
votes
3answers
1k views

How to create a compressed GeoTIFF with the QGIS Clipper tool?

I have a geo-tiff created by Pix4D which is about 375 Mb in file size. I have clipped it to a smaller area using Qgis 2.8(using Raster ‣ Extraction ‣ Clipper), and the output file is about 900 MB in ...
1
vote
0answers
25 views

How to implement a Plotting widget into already existing PyQt4 Interface

I am using Python, PyQgis for about one week and already built a plugin for GIS 2.14 which is -so far- working pretty well. As my next step I want to add a widget to plot data to my already existing ...
1
vote
1answer
33 views

QGIS: startup.py executed twice?

To test something I have a very simple startup.py file in my .qgis/python folder: import qgis qgis.utils.iface.actionShowPythonDialog().trigger() print "Welcome chump" Python console launches fine,...
1
vote
1answer
48 views
+50

How to define border colour for rule-based style using PyQGIS?

I use the following to create a Rule-based style for a given layer which includes defining a label, expression and colour fill: from PyQt4.QtGui import QColor layer = qgis.utils.iface.activeLayer() ...
1
vote
1answer
40 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 ...
5
votes
2answers
1k views

How to remove all selection from all registered layers using QGIS plugin?

I want to remove all selection from registered layer in QGIS using Python. I tried to clear the map canvas using: self.iface.mapCanvas().clear() self.iface.mapCanvas().refresh() but the ...
2
votes
2answers
30 views

Create time series graph with multiple rasters

I need to create a time series graph for a few random cells with known underlying attribute such as "forest" or "agriculture" based on the VCI (Vegetation Condition Index). I have been reading and ...
0
votes
0answers
19 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 ...
1
vote
1answer
33 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-...
2
votes
2answers
34 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 ...
3
votes
0answers
48 views

How to handle large tables in QGIS using python?

I'm currently writing a plugin that calculates values based on a QgsVectorLayer's attributes. To display and print the values I'm using a QgsComposerTextTableV2. I have several problems with my ...
2
votes
1answer
37 views

QGIS create layer from spreadsheet file (Spreadsheet Layer plugin)

With the QGIS plugin 'Speadsheet Layers' i try to create a layer with the following parameters: But I'm just getting a layer with no geometry. I've been playing arround with real instead of ...