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

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8 views

Recast data from one geographic standard to another

I'm working right now a project looking at medical labour supply in rural areas in Australia. I aim to use STATA for most of this analysis, but a change in geographic standards by the Australian ...
3
votes
2answers
111 views

Way to find minimum value from a group of values - QGIS?

I'm wondering if there is a way to find the minimum value of a group within QGIS? Basically I need to find the minimum distance of each unique value in a table of about 5000 records. I can do the ...
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0answers
10 views

QGIS Set Composer Legend to shrink the font size to fit

QGIS 2.10.1. I have read that it is "impossible to make the legend smaller then its contents". Is there a way to set the legend to shrink the font size when re-sizing the bounding box? Or when you add ...
2
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1answer
34 views

What projection to use to get a game map into QGIS?

I have built and maintain a SWTOR game map atlas. At the moment, it's all static jpg maps, but I would like to get the info into an actual GIS software to get more functionality and make my website ...
3
votes
1answer
299 views

How to compute average slope and area-weighted average slope?

I am learning GIS for use in hydrologic analysis. Related to computation of overland flow there are two types of slope that I would like to be able to obtain from GIS. The first is average slope for ...
2
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1answer
42 views

How to create flow maps in Qgis

I have several records from a survey and would like to show flow map from places mentioned in the survey. I have all places mentioned georeferenced and some records mentioned no places and others ...
2
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0answers
17 views

How to randomly select three points in each polygon?

I have two layers: first layer includes polygons of districts, second layer containts points (phytocoenological relevées). The goal is to create a new layer that will contain max 3 randomly selected ...
1
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2answers
34 views

About defining coordinate reference system

I have been wondering about the following issue for several years. In ArcGIS and QGIS you can add data on your map and it aligns perfectly even when the Coordinate Reference System (CRS) is not set. ...
3
votes
1answer
95 views

Where did Processing Algorithms go?

I have recently installed QGIS 2.8.2 on my Windows 8.1 laptop with the stand alone .exe installer. The processing toolbox is missing the GDAL/OGR, GRASS, QGIS algorithms, Saga and the Orfeo Toolbox ...
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1answer
35 views

How to find the intersection length between two polygons using python

I have two polygons and i want to find the intersection line length between these polygons. for geom1,geom2 in itertools.permutations(selection,r=2): intersection ...
3
votes
1answer
695 views

How calculate areas between certain contour lines in qgis?

Sorry for asking a question which I found in similar ways already here, but I am trying this for days and just got no result: How do I calculate the area between certain contour lines (e.g. 0-800, ...
3
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2answers
64 views

How to create a consecutive alphanumeric column in a QGIS attribute table?

I am trying to create a column in the attribute table such that each cell lable is a prefix (M) follwed by a unique number ie M1, M2,.. etc
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1answer
17 views

Creating an intersecting linestring layer from two polygon layers using some tolerance

I have two postgis layers: The first layer contains the sidewalks of my town (polygons in blue). The second one contains the pavements (roads) of my town (polygons in brown). The map looks like ...
2
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0answers
15 views

qgis 2.8.2 always produces minidump on exit

QGIS 2.8.2 on windows 8.1 produces the below error every time it is closed. Anyone have any ideas as to why or possible fixes ?
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0answers
14 views

Text box with automated coordinate reference system in use on Qgis

Using an expression, is it possible to automatically fill a text box placed on the map (in the composer) showing the reference coordinate system of the project? If possible, how would that expression ...
1
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1answer
74 views

How to get a “clean” polygon after using dissolve in QGIS?

I'm trying to obtain the boundaries of shapefile, thus to clean the inside as a matter of speaking. While I had expected that dissolve while get me a proper polygon, unfortunately it still has some ...
4
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1answer
171 views

MapInfo “Boundary Select”, “Sum Attributes”, and “Update Column by Spatial Query” in QGIS? [on hold]

I´m a MapInfo user, I´ve gone over to QGIS and it´s got a lot going for it, except for some "missing" simple features from MapInfo I just can´t do without.... MapInfo Boundary Select - spatial query ...
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1answer
37 views

Communicate relation between two table

At this time, I'm able to create a relation (1:M) between two table or geometries. After, I user Identify tool to exploit the relation. It is only possible to use this feature when your Identify tool ...
6
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3answers
1k views

Rendering and Labeling Shapefile with PyQGIS

I've been running into a few problems working with the QGIS API for python. I've gotten more comfortable working in the python console in QGIS but I run into problems when I try to run the code ...
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0answers
18 views

qgis python: select on screen and change (pre-set) properties accordingly

I have a map with different zones where I have drawn isochrones -where I will arrive within 15 min, within 30 min and so on. The picture attached shows the 15-120 min isochrones. This is set as a ...
0
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1answer
206 views

How to solve sqlite_rtree_geometry_callback error?

I have just installed qgis 1.8 and it show error message the procedure entry point sqlite3_rtree_geometry_callback could not be located in the dynamic link library sqlite3.dll How to fix ...
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2answers
6k views

How Can I change the projection of shapefile in Qgis?

I have a probleme with Qgis. I would like to change the projection of my shapefile, it's about caves in my country. The default projection is set to EPSG:3003, I want to change it to wgs84 EPSG:32632. ...
2
votes
3answers
401 views

Rasterize line shapefile

I'm trying to convert a line shapefile to a raster image at QGis, but my attempts have been unsuccessful. I've tried to use Raster/Conversion/Rasterize and SAGA/Grid - gridding/Shapes to grid, but to ...
2
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0answers
31 views

Merge Line Segments based on their length in QGIS

I have a layer containing line segments which are connected by their endpoints (e.g. as within a street network). I'd like to merge (union) polylines within this layer into one feature until following ...
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2answers
54 views

Fix Polygons to be true Rectangles

I got a featureclass polygon of 4 point polygons that delineate the coverage area of a georeferenced image; these polygons will later be map sheets. Anyway I discovered some of them are not true ...
0
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1answer
33 views

Points and polylines representation of coordinates in QGIS? [duplicate]

I am working on the "Jakarta Bay", Indonesia. I have a shapefile for the Indonesian coastline and I clipped my region of interest using an appropriate polygon. I also have points that are located ...
10
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8answers
8k views

How to georeference a vector layer with control points?

I have a non-georeferenced vector layer that I need to be georeferenced. With raster layers the task is easy and straightforward, but I have no idea what should I do with my vector layer. I have a few ...
3
votes
1answer
24 views

Problem exporting registers with the land registry in DXF continuation (suite) in reprojection

I visualize (display) a municipality with the plugin register with the land registry in spatiality and in projection Lambert 93. I need the bottom on Autocad in projection CC47 thus I re-throw ...
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0answers
25 views

QgsVectorLayer from delimitedtext fails

I am having trouble loading csv files into layers using QgsVectorLayer(). I know this looks like a repeat, but I have carefully read Create a script to add delimited text layer in QGIS and ...
2
votes
1answer
44 views

QGIS LTR vs other release

Just after some advice with respect to the QGIS LTR schedule. Our IT managers have recently intervened in our use of QGIS (a State Government Authority) and are wanting to put in place a policy to ...
0
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0answers
12 views

QGIS to Leaflet Projection Weirdness

I've been using the mmqgis tool to create a hex grid. It loads up in QGIS looking good, but when I save it as geojson and load it up in leaflet it gets stretched (see attached). It starts life as ...
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0answers
8 views

Adding to signature list from ROI list does not work?

I'm trying out QGIS with SCP, but I've run into some problems First of all, my setup is as follows: QGIS version 2.10.1-Pisa on Mac OSX Yosemite 10.10.5 compiled and running against qt 4.8.6 ...
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1answer
19 views

Cut/Clip/Split a polygon with another polygon from same layer (Editing) - Qgis 2.8.1

To not have overlapping polygons/features I normally use a practice where I use one or more polygons to clip/shape other polygons. This is often much faster than tracing when adding polygons etc. I ...
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0answers
22 views

How to use interacting PostgreSQL/PostGIS triggers in QGIS?

I use point geometries (table 'label_point') to place multiple labels on polygon geometries (table 'soil'). After doing layer edits I've to update the affected label_point features. Therefore I've ...
3
votes
3answers
752 views

How to change layer transparency without changing border lines?

I have a raster image of elevations. I have added a vector shapefile that contains local political divisions. I want to keep the elevation colors, but I want to keep the black lines representing the ...
1
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1answer
37 views

change SRID of shapefile and QGIS

It is possible to change the SRID from a shapefile to another SRID in QGIS ? I have a shapefile in 2100 srid and i want to change it in 4326 SRID.
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0answers
15 views

QGIS 2.8 composer image

I have a table with photo's, i now want to make dynamic map with discription en showthe photo. In the composer with atlas, so i can produce about 1000 pdf files Is this possible?
0
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1answer
43 views

Querying related tables in QGIS

I have a parcel layer and a table of property sales. I have the two tables related (it is a one-to-many relationship) in a QGIS project so that when you click on a parcel you see all the related ...
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votes
0answers
35 views

How can i make image of shape file using python in QGIS? [on hold]

Here I am trying to below code, but it give me error. import shapefile import Image, ImageDraw # Read in a shapefile r = shapefile.Reader("K:\TM_WORLD_BORDERS-0.3\Mississippi\mississippi") # ...
1
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1answer
45 views

Is it possible to change the geometry without startEditing the layer

I am working in c++/QT 4.5 with the QGis 2.8.2 API. I had to change the geometry of features in a layer each second. Each second new data comes from the Ethernet connection, the application gets the ...
1
vote
1answer
174 views

QGIS 2.8 starts with an error and I am not able to run Python console

I have installed QGIS 2.8 - Wien on Linux Red Hat 7. Unfortunately when I start the application I got this python error: {Couldn't load plugin 'processing' from ['/usr/share/qgis/python', ...
0
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0answers
26 views

QGIS display wrong histogram statistics for float32 raster

While trying to display a float32 raster created with TauDEM, QGIS displays a min/max of 1,1 although the .aux.xml file contains the correct values. I am using QGIS 2.10.1 both on Windows 7 and Mac OS ...
2
votes
1answer
37 views

Remove inner rings from QgsGeometry polygon in QGIS Python

I am a QGIS python user. I want to iterate over the rings of a polygon to remove holes in the polygon, so: I need to iterate over the rings in a QgsGeometry polygon I need to detect the main ring ...
2
votes
1answer
40 views

How to add a map created in QGIS to a Matlab plot

I am generating a number of plots in Matlab. I want to overlay these over maps I have created in QGIS. I thought the best way would be to import the maps as a geotiff into Matlab and then overlay my ...
0
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0answers
16 views

Grids stay visible in QGIS Composer Legend when turned off in project

I am using QGIS 2.8 to create a template for a dataset library. Lots of layers - vector and grids. The grids stay visible in the legend even when turned off in the map. I am using the "Filter Legend ...
2
votes
2answers
29 views

How to load stored composer from project file in standalone QGIS application?

I would like to load a .qgs file and get a composer from it, but I can't figure out how. Is there a way, or do I have to read the xml myself and individually set the appropriate values for the ...
0
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0answers
20 views

Viewshed analysis plugin on QGIS keeps resulting in errors

I've been trying to test the Viewshed analysis plugin on QGIS 2.10, but it keeps giving back error messages. I've tried to reduce the radius area and have also reprojected both my DEM and my point ...
1
vote
1answer
115 views

How to fix the broken MGRS Tools plugin?

Here the case: i have a plugin installed in .qgis2/python/plugins that remains broken and i cant make it work. I've found it here https://github.com/volaya/mgrs-tools. If any of you know the way to ...
0
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2answers
277 views

How to get image pop ups in QGIS?

I have a map of an area and georeferenced photos. I need to be able to bring the pictures as points and then be able to click at a certain point and an image pop up.
1
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2answers
53 views

Make a new shapefile from parts of two shapefiles

I have tried all day to connect two shapefiles, crop a part of them, and save it into a new Shapefile. In the image you can see two Shapefiles and inside of the square is the part which I want to ...