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

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2
votes
1answer
102 views

Layer with custom UI not working properly

I have a problem with QGIS 2.4 when introducing layers with a custom UI. More precisely, widgets such as CheckBoxes are not recognised as such (appear as Text Edit in Attributes) and the corresponding ...
0
votes
0answers
5 views

Help with georeference: imported Tif is dark gray

Using georef on QGIS 2.6 I import a TIF file, and expect the import to show an image that has black lines on a white background (with some other colors here and there). the file, 96MB, imports, but ...
0
votes
1answer
29 views

Fill polygons via data-defined pie charts

I am trying to summarize my polygons by each's distribution of some variable. To couch the discussion, let's say we wanted to summarize the demographics of each county (of a small state) by it's ...
8
votes
3answers
161 views

Calculating all distances from single points to multiple polygons

I have two layers: a point layer defining properties (95 objects), and a polygon layer defining plots of land associated with the properties (211 objects). Each point relates to one or more polygons. ...
0
votes
0answers
6 views

QGIS procedure for Multidirectional, oblique-weighted, shaded-relief?

Is QGIS capable of the multidirectional, oblique-weighted,shaded-relief method described at http://pubs.usgs.gov/of/1992/of92-422/of92-422.pdf ? If so, what are the steps necessary in QGIS to ...
2
votes
1answer
134 views

Problem with import qgis.core when writing a stand-alone PyQGIS script

I am trying to write a stand alone python script in windows 7 that uses qgis.core and various other qgis libraries. I have found an old question on this subject here: How to write standalone Python ...
1
vote
0answers
39 views

Connect to QGIS 2.6 Python Plugin function via button on custom feature form

I am trying to connect to a QGIS 2.6 Python plugin function via a custom feature form button. On my feature form, I'm attempting to do a few things : enable the updateButton only if the ...
4
votes
1answer
262 views

Snap points to line and calculate chainage using Open source GIS

I have a line layer (representing a pipeline) and a points layer (representing valves) and I would like to calculate the chainage of the valves along the pipeline. I assume that I would first need ...
3
votes
1answer
38 views

How to always disable the “add saved file to map” checkbox in Save as …?

I often use the "Save as.." dialog and just want the exported geojson file there. But he always enables the checkbox "add saved file to map". I really dislike it that way and it does not make any ...
1
vote
1answer
28 views

PyQGIS: feature added signal throws an error message

For my PyQGIS plugin 2.2, I try to: def logFeatureAdded(self,layerId,addfeatures): message = str(layerId) + " has features added: " for feature in addedFeatures: message += str( ...
3
votes
2answers
26 views

Send signal when attributes modified - QGIS 2.6

For a QGIS 2.6 python plugin, I am trying to send a signal when an attribute value is changed (values for an existing feature are updated or added and the attribute form dialog is accepted). This ...
1
vote
0answers
14 views

Custom QGIS 2.6 map tool - mouse click and release issue

I have create a custom map tool for QGIS 2.6, implementing a canvasReleaseEvent and canvasPressEvent. I can't though get the signals to work on one single mouseclick (I have to click twice). My map ...
1
vote
2answers
26 views

How to create an image of mean values from multiple NDVI images?

I have downloaded MODIS NDVI images of 12 months. I would like to create just 1 image with the mean values. I tried using IDRISI's 'NDVI compositing utility', but I get an error. Is there a way to do ...
3
votes
0answers
17 views

How to display features only if labels are displayed?

In my maps there are several point layers, and each layer has a different labelling rule and priority. Sometime the point density is too high and the labelling engine is not displaying some labels, ...
0
votes
0answers
21 views

How to deal with contour error “Exception encountered: invalid index”

I have include vector layer using postgis database with filter(data between two dates) it work fine but after adding when I trying to make a contour from it I get error Exception encountered: ...
4
votes
3answers
97 views

Alternative to OpenLayers plugin for QGIS?

Are there any alternatives to OpenLayers plugin to have Google / Bing maps for QGIS projects? I need an high quality cartography (both aerial and street view) but OpenLayer plugin do not allow to ...
3
votes
3answers
81 views

Spacing a set of points

I have a shapefile of a set of points that I want to space out. I DO NOT want to do this using line interpolation as I run the risk of placing a point where there wasn't one before. I can load this ...
0
votes
1answer
18 views

How to convert total station data (coordinates) to 3D model? [on hold]

i have my coordinates in .csv format and i want to convert it to a usable 3D model. How do i go about this or what software can i use to achieve this?
1
vote
1answer
12 views

Change detection between two classifications in QGIS?

I have two raster classifications. They have the same number of classes which use the same ID (each class has a unique ID). I would like to get information on the changes between classes i.e., class 2 ...
0
votes
1answer
277 views

visualize bounding box to a polygon

I try to make plugin in QGIS that compare 2 bounding box data, ex: (-32.61442167739459, -32.017601026186576, 13.015663782506067, 13.428145228091406) and (-38.6102467739459, -38.017601026186576, ...
2
votes
1answer
19 views

How to display QGIS plugin panel “OSM place search”?

It is possible to hide the panel for the experimental QGIS plug-in 'OSM place search' - but the panel is not listed (to re-display) under the menu item View | Panels. How can it be re-displayed?
1
vote
1answer
19 views

If statement using QgsRasterCalculator

So in the sequence of my previous question (Can't use Raster Calculator with two different rasters), I am stuck again in my project. With my source rasters, I created 3 different outputs using ...
3
votes
0answers
53 views

Correct georeferenced LiDAR data

Often I obtain LIDAR data for concept studies and conventional survey (in dxf format) over a small portion of this. The LIDAR typically covers the broader area and is used for broader studies, ...
3
votes
2answers
1k views

Is there an option to remove duplicate polygon labels in QGIS?

I would like to know if there is an option in QGIS labeling engine which would remove all the duplicate labels. My polygon layer contains a few features with same name. So when labeled it becomes a ...
3
votes
3answers
6k views

Calculating the minimum distance between points and polygons in QGIS

I have two vector layers: one point and one polygon and I want to calculate the minimum distance of each point from the polygons (ie the distance from the closest point of the closest polygon). Is ...
2
votes
3answers
19 views

QGIS: Get data in raster DTM from vectorpoints

I have a vector layer of points. Can I get an output from a rasterlayer which contains DTM-values (height) determined by my points placement?
6
votes
3answers
609 views

Random value calculation in QGIS

Is there a way to do a random value calculation within a range in QGIS? I have been able to do this within ArcMap Field Calculator with the following code: Dim max, min max=20 min=5 ...
0
votes
2answers
14 views

QGIS upper round in field calculator

I need to to in the field calculator the following calc: toint(Field1 / 25.0) but i need to round the result to no decimal places but upwards. Exmaples: If 17/25 result should 1. If 25/25 result ...
5
votes
1answer
290 views

Calculating Topographic Exposure with Raster Calculator

I need you help trying to calculate Topographic Exposure (TOPEX) on a DEM in ArcGIS. I am trying to figure out wind exposure on a DEM with 25m cells. There is a great blog post where someone explains ...
0
votes
0answers
11 views

How to equally space points in a line using QGIS? [duplicate]

How do you place points in a straight line the same distance from each other in QGIS? Thanks
4
votes
1answer
35 views

Qgis2Threejs returns empty page

When i try to make 3D scene from DEM with Qgis2threejs it creates a empty html page. I also try to make 3D thematic map from shapefile with the same result. I have also check my browser and it ...
1
vote
0answers
113 views

Problem using grid with a vector layer [on hold]

I need to establish a model of maritime pollution and I try to use the grid option to work on ocean sectors. I tried to use my grid on a vector file, .shp, with points. Each point is a maritime ...
1
vote
1answer
113 views

Smoothly interpolating Polygons from set of coordinates?

I'm still quite new to QGIS and I'm using it to display and analyze my soil data. I have point information on the distribution of the soils in a specific area and I need to create a soil map from ...
4
votes
2answers
59 views

QGIS batch shp transform

I have a large number of shape files in OSGB (EPSG:7405), with no .prj file that I would like to convert to WGS84 (EPSG:4326). Can you let me know if this is possible in Qgis and, if so, how, and, if ...
3
votes
2answers
674 views

keep the same field headers after joining a table to a shape file in QGIS

I noticed that after joining a table to a shape file the headers of each fields in the table used for the join are changed by QGIS and they are attributed to a different name. For instance, i had a ...
0
votes
2answers
142 views

Can Vector grid shape file be clipped with Satellite image in qgis?

I am working in open layers plugin in QGIS. in order to project the satellite image wit respect to vector shape file i am having, Andre Joost suggested me to create a vector grid with crs sysytem of ...
8
votes
1answer
91 views

Can you use wildcards for column headers in Field Calculator?

I know you can use wildcards for fields like so (in the Field Calculator): case when "column" ILIKE '%example%' then 1 else 0 end Can you do something similar for the column headers themselves? I ...
1
vote
1answer
17 views

Why use QgsFeatureRequest() when iterating?

I am unclear on why one should use QgsFeatureRequest() when iterating over a file’s features. Let’s say I would like to print out all IDs in my currently active dataset. Now, most examples will ...
2
votes
0answers
23 views

Shapefile layers in QGIS don't display unless I zoom out

I have two shapefile layers in a Qgis project that have problems with zooming. One is a line I copied/pasted in a new layer from a set of height contours and the other one is a polygon layer I created ...
1
vote
1answer
63 views

How to select and zoom in features from a QGIS Python Plugin

I'm very new to Python. I'm trying to find a way to select and zoom to the features from a QGIS layer. I've created a plugin and built a custom form. I have 3 values from the form which I need to ...
2
votes
1answer
116 views

How to load a *.qgs file in a C++ QGIS standalone app?

I'm using QGIS-2.4.0 API to develop a standalone app by C++. I saved a test.qgs file in QGIS Desktop software, in the project, there was one layer and it was visible. Then I loaded the test.qgs ...
2
votes
1answer
68 views

Run processing toolbox outside QGIS in standalone app

I am developing a standalone app in Python, using QGIS libraries including processing algorithms. I am developing in Linux environment and I put the libraries in a folder. Also I put the processing ...
3
votes
2answers
25 views

Qgis - Projection Problem with EPSG:2272

I work in both Qgis and ArcGIS. Most of my data has been created using ArcGIS and all of my data should be in the EPSG:2272. When I add my data to Qgis, it does not recognize my projection and gives ...
4
votes
2answers
40 views

Adding Eastings and Northings as attributes automatically to a point layer in QGIS

I have a point layer that I am adding to and am working in British National Grid. Two of the columns are Easting and Northing. When I add a new point I want these two columns to be filled out ...
7
votes
2answers
549 views

How to write scripts that can call on both Arcpy and PyQGIS?

I have spent quite a bit of time looking for a clear answer this topic and have still been unable to really accomplish my goal of accessing PyQGIS in a stand alone script. Parts of answers have been ...
1
vote
2answers
39 views

How to set the QGIS display to show decimal degrees?

Using QGIS 2.6.1 Brighton. I am trying to set the CRS for the project to display Decimal Degrees, where it is defaulting to Feet. I can change it in the Properties Dialog, but it does not change it, ...
2
votes
1answer
20 views

Visualising a raster PostgreSQL table in QGIS

I have imported a raster tif image into PostgreSQL with this command: raster2pgsql -s 32643 -I -M filepath.tif -F -t 100x100 public.databassename > filepath.sql And imported the output SQL file ...
2
votes
1answer
36 views

Merge multiple bus stops with same name

my question is similar to this one, but it's not answered sufficiently: How to merge points (bus stops) in QGIS manually or programmatically? I have OSM-transit data with bus stops. Some stops have ...
1
vote
2answers
156 views

render geotiff tiles as a map layer

i have the following problem: i have downloaded tiff files with gMapMaker and transformed them to GeoTiff using the associated .map files in QGIS. now i want to render these GeoTiff files to use them ...
1
vote
0answers
14 views

Error when using r.watershed

When i am calculating LS Factor using Grass r.watershed the error "Raster map or group not found" (image below) keeps turning on. I don´t understand why this error happens if i am using a elevation ...