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

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1answer
96 views

How to get path for layers listed in a combobox?

I want to get the path of a layer in my plugin, in the console it works fine but in my plugin it gives me the error AttributeError: 'NoneType' object has no attribute 'dataProvider' def run(self): ...
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0answers
36 views

Using QGIS in medical Science? [closed]

I was wondering if anybody would be interested in collaborating? My Idea is using QGIS to analyze and quantify Immunofluorescence raster images of cells from human serum.
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0answers
37 views

How to compute and label distance between points on a line?

I have a line and i want to find and label the distance between the nodes (like the cad aligned distance). v.distance outputs an empty vector file. Is there another way?
11
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4answers
1k views

How to model a graveyard - one point per deceased or one per grave? [closed]

This is a continuation of my previous question about our project on how to economically get away with the implementaion of a graveyard in a GIS system… On the graveyard we can find Regular ...
1
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2answers
54 views

How to remove a certain number of digits from the front or end of an attribute field?

Can I use the filed calculator in QGIS somehow to remove the first 4 numbers in all attribute fields in a column? Example 16011234 -> 1234 EDIT: Silly, I can just subtract with 16000000 in this ...
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0answers
30 views

Georeference Error Messsage QGIS

I'm trying to georeference a 1922 map of Africa by Bartholomew. (found here http://www.davidrumsey.com/maps5268.html). I have it in QGIS and currently the Raster has the default CRS (WGS 84). I have ...
2
votes
1answer
119 views

How to display a picture in QGIS custom form?

I'd like to integrate an UI file as a form in QGIS 2.8. The UI file is created in QT Designer. One of the attributes in the attribute table is a filepath to an image. I'd like to display the picture ...
0
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1answer
85 views

QGIS C++ Hello World example crashing

I have written a very simple C++/Qt application using QGIS comprised of a single "main.cpp" file as below: #include <qgsapplication.h> int main(int argc, char ** argv) { QgsApplication ...
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1answer
179 views

QGIS Wien 2.8.1 RuntimeError concerning the sip module on Win 7

I am running windows 7 64bit and python 2.7.9 I just installed QGIS Wien 2.8.1 and it crashes on start up with the following code: Couldn't load PyQGIS. Python support will be disabled. Traceback ...
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0answers
123 views

Limit Extent of OpenLayers Map in QGis

I am trying to work with a OpenStreet map of Ontario, using the OpenLayers plugin. The problem is that the entire global view renders, slowing down my work. A couple of solutions come to mind: ...
0
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1answer
42 views

Merging SHP lines with attribute data combined?

I have one shapefile which contains hiking routes and another shapefile which has ski routes. Sometimes they follow the exact same path. In QGIS if the lines mentioned above are in the same SHP I ...
2
votes
1answer
209 views

Processing plugin Python error on startup of QGIS 2.8.1

I've been running QGIS with no issues for several versions now, but after I upgraded to 2.8.1 Wien I had trouble running two plugins: qgis2leaf (which I believe depends on Processing) and Processing. ...
1
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0answers
74 views

Why is SAGA kriging slower in QGIS than in SAGA itself?

I'm using QGIS for a while. In my opinion the SAGA kriging tool (processing toolbox) is very slow. Is that an QGIS issue? I tried to interpolate a point layer with 300.000 points (I know it is big) ...
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0answers
24 views

install python packages for qgis? [duplicate]

I need the twisted framework (Python) for a qgis plugin on Windows 7. I installed it with the pip installer. When I want to start the plugin it doesn't find twisted. When I start a python interpreter ...
0
votes
1answer
83 views

Merge touching polygons with keeping their attributes

I've got a layer of polygons Although they all in the same layer, each polygon own some unique data like the date of this polygon and an amount it possess (a number). I want to join/merge all the ...
1
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0answers
41 views

Incomplete results from an intersection

I am trying to map the density of buildings in flood-prone areas. In order to do that, I created a grid of equal-sized squares. I want to intersect the layer of buildings with the grid so I can ...
1
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1answer
24 views

Digitizing 2-node lines?

I tried digitizing in to a new sqlite line layer with autoincrement id ticked..... I want to create a 2-node line, but there seems to be a minimum limit of 3 nodes. Is this correct or am I doing ...
1
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1answer
69 views

How to remove “ERROR 1” messages from a standalone QGIS script?

I am running a standalone script for QGIS which creates a high resolution grid and clips shapefiles onto it. Works perfect if the cell width and height have a high values (in my case, >200m for both). ...
3
votes
0answers
56 views

How to offset polyline geometries (not symbology) using QGIS?

I have a polyline layer which has a road network digitized, up the center, in both directions however the polyline are sat "one on top of the other". I can display the lines separately by ...
0
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0answers
23 views

QgsMapCanvas render is very slow

I use QgsMapCanvas in my C++ application. When I add my layers to project in QGIS (2.6.0) they are rendered quickly (I use PostGIS to store the data). But when I load the same layers in my application ...
2
votes
1answer
50 views

Automatically adding Z-values from a DEM to an already created polygon

We have excavated a very large 5.000 year old fish fence, which was documented by photogrammetry, and is now being digitized. I started digitizing the orthophoto in QGIS and everything is cool. Now ...
2
votes
1answer
76 views

Change layer datasource in qgis project with python

I have different qgis project with some layer and their datasource like ../my_path/my_file.shp. I need to insert this shp file to a remote db. For do it i use shapefile from PGeo module and it's work ...
3
votes
1answer
94 views

How to create a virtual field in QGIS by Python Console?

Is there any example about how to create a virtual field and subsequently change the attribute of a non-virtual field without wiping out the virtual field? Both are required to be done in the Python ...
1
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2answers
184 views

Generate PNG/JPG maps from multiple ASCI/GeoTIFF in Python/GDAL

I need to generate maps (saved in PNG, JPG or PDF) from raster files (for each file - one map) which meets following criteria; * each map has exactly the same color pallette, so that it will be easy ...
1
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0answers
48 views

Considering “holes” in Voronoi polygon creation in QGIS?

I am trying to create voronoi polygons in QGIS that would consider "holes" in the general domain. An example would be: I actually created the Voronois in this image using QGIS through the GRASS ...
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0answers
17 views

QGIS modal value within distance

I have a vector layer with several values associated to each polygon. I then have a point vector layer. I want to get the mode of each value for polygons within 500 km of each point. I'm not sure how ...
2
votes
1answer
73 views

QGIS plugin problem, can't reach objects in a Qt-based Stacked Widget

I am creating a plugin for QGIS but am having trouble with the Qt components. I have used Plugin Builder and Qt designer to create all necessary files for the plugin. I want to use a QStackedWidget ...
2
votes
1answer
60 views

merge two DEMs of different resolutions? [duplicate]

I have two DEMs, the first one is in 30 meters of résolution and the second: 5 meters, and will like if there is a possibility of merging them to extend the area where I do my research?
0
votes
2answers
95 views

Points within polygon in QGIS [duplicate]

I have a shapefile with polygons. And I have a csv file with points. Now I want to know for each point in which polygon it is situated. Every polygon has a number, so I want to create a file where you ...
2
votes
0answers
26 views

Error using grass script v.lidar.edgedetection

I'm in trouble with the grass script v.lidar.edgedetection. When I try to filter an xyz format dsm the script starts but at the end of it an error message appears (see attached image). Somebody ...
1
vote
1answer
59 views

How do I create a spatial filter on a layer?

I have a layer that draws points in a PostgreSQL (PostGIS) database. The problem is, all points in the table are being drawn. I want to limit the points drawn to a spatial query. How do I limit the ...
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0answers
23 views

Track administrative changes with QGIS

I use QGIS. I have two shape files with the administrative boundaries in two differnet years. These boundaries have changed: some wards (smallest administrative area) remain the same, some are newly ...
3
votes
2answers
212 views

How to load a raster layer using PyQGIS?

I need to load a raster file from the provided file path. I wish to use it further in the Raster Calculator. I wrote a function which converts string (I assume it is a file path) to a raster object. ...
1
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1answer
89 views

QGIS processing script: Move points by specified distance and add segment

I try to move points (they come as WGS84, but I'm not sure if it works with unprojected CRS) by a specified distance and connect original and new point with a line segment with the below script, but ...
1
vote
2answers
145 views

How to overlay a Lat/Long CSV and NAD83 Shapefile in QGIS?

For reference I am new (as in a few hours of messing around) to GIS. I have a shape file/accompany projection files ect: CURRENT.prj CURRENT.shx CURRENT.shp CURRENT.dbf CURRENT.sbx CURRENT.sbn I ...
0
votes
0answers
13 views

send attribute from 75,000 object polygon to 20Mil point database

I have sql server 2008 r2. I have two tables: PropertyParameters and REF_GEOID. Property Parameters has four columns: PropertyID, ParcelID, Lat, Long. REF_GEOID has two: GEOID and GEOM. GEOM is a ...
0
votes
1answer
60 views

Creating KMZ files from QGis using GarminCustomMap plugin

I am new to GIS and QGIS, and really lost with some basic QGIS concepts. I have installed the GarminCustomMaps plugin, and by usign the default plug-in settings I am able to generate a single tile of ...
1
vote
1answer
137 views

How to create dissolved buffers in QGIS with PostgreSQL/PostGIS?

Creating a dynamic buffer in QGIS I use the following query: CREATE VIEW buffer40units AS SELECT gid, st_buffer(geom,40)::geometry(polygon, 31492) AS geom FROM point; Now I want to dissolve ...
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0answers
32 views

Action on group of features from layer in QGIS?

I need to implement a rename action on a selected group of features in a certain order. The idea is that I would rename one feature and then select the features that are 'next in line' and execute a ...
1
vote
1answer
46 views

assigning random points to unique values

I have generated random points in qgis and would like to assign the value of their geometry to a unique column in another table. I would like to do this in qgis or postgres or spatialite. Table A ...
1
vote
1answer
160 views

How Does Ogr2Ogr Simplify Work?

Can someone explain how the ogr2ogr simplify works? I am trying to use raster data which has a spectral resolution of 30m. The vector file that I am trying to import into Google Fusion is large in ...
1
vote
0answers
30 views

Transform GeoTiff to WMT

I'm not a gis specialist at all so this question may seem dummy to you. I have a GeoTiff base of images (hundreds) I'd like to transform to a WMTS repository to put behind a web server. Web pages are ...
1
vote
1answer
88 views

Calculate area intersected areas, problem [closed]

(I'm working in QuantamGIS) I intersected two layers creating a new layer. Within the attibute table of this new intersect layer i would like to calculate the new areas. However, it just doesn't ...
2
votes
1answer
141 views

Strange circles have appeared on QGIS map?

Why are circles appearing on my map? It started after using QGIS dev build 2.9 and now appears even on 2.8.1. Also I've noticed that the usual list of CRS does not appear while using the dev build. ...
1
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0answers
34 views

Is there a way to export entire projects or groups to KMZ?

There is a lot of questions about exporting single files, Im trying to see if there is a way to export an entire group in QGIS to a .kmz file that can be opened in google earth. I know there is a way ...
1
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0answers
20 views

Display tabs don't appear when files and folders are selected in QGIS?

My setup: QGIS 2.8.1 Wien on OS X 10.10.2 I'm a complete beginner at GIS and I'm having trouble on getting the Param/Metadata/Preview/Attributes tabs to appear in the Display Window. When I select a ...
2
votes
0answers
50 views

ST_Buffer with segment AND endcap parameters

Making a QGis plugin that buffers a line and I want to declare a high number of segments and a flat endcap. ST_Buffer(geom, 40, 25, 'endcap=flat') This doesn't work with both parameters entered, ...
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0answers
36 views

QGIS topology overlap check

I have checked topology rule must not overlap with and i get error The problem is that i have check this many times, and made hole vertex after vertex so it is not possible that these objects ...
2
votes
1answer
95 views

Clip layer with selected object from another layer in QGIS

In ArcMap, I can clip a layer with selected objects from another layer by using the editor toolbar. I want to do the same operation in QGIS. I want to create holes in the landuse layer by selecting ...
1
vote
1answer
34 views

Change name of category heading in legend

In QGIS 2.8.1, I have a SHP layer. In the display it is categorized by one of the fields, "Sannsynlig". In the table of layers and in the legend, it is also identified as "Sannsynlig", as the name ...