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

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9 views

QGIS raster calculator wrong output

I am trying to create a mask from a DEM (SRTM tile) using raster calculator in QGIS. I have performed the same operation in ver 2.6 with no problem but in the current version the output is incorrect. ...
3
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2answers
125 views

What is the theory behind graduated symbols in QGIS?

QGIS offers 5 methods of classifying vector map data (quantiles, equal interval, etc). What is the theoretical base of these methods? If there are certain methods suitable for certain types of data or ...
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0answers
36 views

What causes some shapefiles to be fat? Can you effectively reduce size of a fat shapefile?

I have a shapefile that contains all counties of Poland in one shapefile. The shapefile is provided by central cartography agency. The file with counties they provide is around 30mb. The same ...
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0answers
12 views

QGIS 2.6 - installing exifread for photo2shape plugin

I've already seen Error loading plugin photo2shape even after installing exifread module and Error installing Photo2Shape QGIS 2.6 for Mac, and other forums, but can´t make it work. First I installed ...
2
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0answers
16 views

Merge several images and Export a GeoTiff File

I have approx 500 geo-referenced images that I was hoping to merge into 1 geo-referenced file, and export it as a single geotiff file. To be used in AutoCAD Civil 3D I know I am pushing my luck and ...
3
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2answers
40 views

Using folder wildcards to copy files with Python

I would like to copy the data of one specific shapefile from a specific folder ("Grid") to a number of folders containing the name "Country". The country shapefiles would keep their original name. ...
1
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0answers
17 views

importing MapInfo georeferenced ratser on qgis 2.2

I do not understand why loading mapInfo shapefiles is possible in Qgis but for the georeferenced image file, is there any possible reason for this? My major concern is that, so far georeferencing on ...
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0answers
10 views

QGIS, How to label a layer in different font sizes, shrink to fit in polygon or a multiple line label?

I am just trying to figure out how to label a polygon layer to fit its size in QGIS. or if its very long title should break in line and scale, i did some research but couldn't find anything helpful is ...
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1answer
18 views

How to change GK-coordinates to UTM with the field calculator in QGIS?

i have a qgis project in ETRS89 (UTM) with some vectorshapes. i already transformes them from GK into UTM. but now the attribute table still show me the GK-coordinates. HOW can i change it? with the ...
1
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1answer
33 views

How to generate line segments between all points

How do I create a vector layer with a network of line segments drawn between every point in another vector layer? Basically, I am trying to create something similar to a hub/spoke network, except ...
2
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0answers
9 views

Concentric Ellipses around polygons as a representation of density

I have someone who has given me a thumbnail of a map with some concentric ellipsoids placed in estimated high density locations for our business. One location has three, and two other location have ...
0
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1answer
19 views

Extract Elevation of Points from DEM using Python QGIS or GRASS

I am utterly new to GIS, so please bear with me if I am providing incomplete information here. I have a DEM file (.dt2). What I am looking to do is as follows: take a series of points specified as ...
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1answer
40 views

Adding points defined by Latitude and Longitude to map using QGIS?

I have an OS map on which I want to display points defined by Latitude and Longitude, but the map coo-ordinates have values I do not recognise or understand. The image shows the map, with my first ...
0
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0answers
20 views

query from shapefile to obtain all long, lat from a point table

So I have two files, one is a shapefile with multiple shapes and shape-length, and another file with long, lat coordinate points. I would like to query for each shape in shapefile all the points ...
1
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1answer
20 views

Editing attribute table on QGIS 2.2?

I work on QGIS 2.2, and I am unable to edit my attribute table to change the field type from string to double. I have gone through several tutorials. - I can not run the table manager plugin, ...
1
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0answers
18 views

QGIS Partitioning Regions

I have to polygon shapefile maps in QGIS that cover the same area. One with ~90 polygons (call them regions) and the other with about ~800 polygons (call them zones). I want to add a data column in ...
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0answers
16 views

Generalize a selected part of shapefile

I see v.generalize takes the whole shapefile as input, but is there a way in QGIS to generalize/smooth selected part of a shapefile? I will select the part in Node Tool and then use v.generalize tool. ...
3
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1answer
28 views

Modifying straight line segments so they follow geodesic / great circle paths using QGIS

I have a kml file showing a dodecahedron stretched across the surfce of a globe, which I downloaded here: http://montalk.net/cgi-bin/coordinates.py I would like to re-project this dodecahedron so I ...
1
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1answer
24 views

Is it possible to overlay ungeoreferenced raster images in the QGIS Desktop Browser?

Afternoon ladies and gentleman, I work for a company that produces Mining Investigation reports for property in the South West of England and I have spent the last 12 months digitising abandoned ...
2
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1answer
25 views

Not able to load any Raster File using QGIS Python

I am trying to run an elementary piece of Python code, that simply loads a dem file as a raster accessing the QGIS Python API. On the embedded console (within the QGIS application GUI), it runs fine ...
1
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1answer
25 views

Rename output shapefiles in PyQGIS

I have a shapefile which resides in a folder, gets processed and the output is saved in another folder. Before the output, I would like to rename the shapefile slightly differently from the original: ...
1
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2answers
43 views

QGIS Rule Based Rendering

I am looking for an example of how to use the QgsRuleBasedRendererV2 to filter features of a layer based on an attribute value (0 or 1). Has anyone done this in Python or C++?
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1answer
38 views

QGis 2.8.1 crash even after reinstall

I've been using QGis for quite a few years. I normally update QGis to the latest version once it is released on qgis.org, without uninstalling previous versions. I've never encountered any problems ...
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0answers
28 views

how to make an intersection between a shapefile and A WMS layer in QGIS 2.8.1

I am using QGIS 2.8.1 I think what I want to do is an intersection between a shapefile and A WMS layer, both in vector format. I have 1 small vector layer that consists of different forest stands, ...
2
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2answers
62 views

Procedure putting online a graveyard in a GIS

I would appreciate some advice. I’m not an expert in GIS but recently I studied a bit, came on different sites. Among others QGIS, MangoMap, ArcGIS, … etc A group of 6 small towns in Belgium wants to ...
2
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2answers
33 views

Overlaying Shapefile with projection and raster (without projection but with defined extent) using QGIS?

I'm trying to overlay a shape file into a raster. The raster has no defined projection but it's a global raster with extent 0, -1800 : 3600, 0. I tried "on the fly CRS" transformation and followed the ...
2
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1answer
25 views

Adjusting extents so that same-CRS shapefiles overlap in QGIS?

I have two files with identical projections/CRS. Using both OTF on & off I cannot get them to overlap: one shapefile contains coastal polygons of Massachusetts, and the other shapefile contains ...
0
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1answer
37 views

polygonize giving duplicated polygons

I am trying to reproject some ascii files and convert them into shapefiles. I am new to python but looking at some code online and help files I was able to write the following code to run on Python ...
2
votes
1answer
38 views

GPS Live tracking with qgis android

I have a Tablet 10.1 notes on which I installed QGIS Android (v. 2.8) and a Garmin GPS 62 stc. So I tried to do the "live GPS tracking" by connecting through the USB cable the GPS to Tablet. Next, ...
1
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2answers
60 views

QGIS: circular buffers

I have a coastal line layer ( us-medium-shoreline from http://shoreline.noaa.gov/data/datasheets/medres.html ), which is loaded into a project with On-The-Fly reprojection ( WGS 84 / World Mercator ...
0
votes
1answer
30 views

QGIS: custom build, python error

I have built qgis source on windows 7. Libs have been downloaded from osgeow4 site. I even installed postgress as a standalone. I am getting this error when the app launches.. File ...
0
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1answer
34 views

Script not processing shapefiles from one folder to another

I am working on a script which takes shapefiles from one folder called "Original files", process them and then output the results into another folder named "Processed files. I asked a question on how ...
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0answers
27 views

Cost_Matrix Distance: Vehicle routing problem!

I'd like to calculate the "real distance" between one source and many targets, such as we do in the "vehicle routing problem", in order to get the matrix distance at the end. after using the osm2po, ...
1
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0answers
20 views

QGIS heatmap misplaced over dataset [duplicate]

First of all I'm a complete noob when it comes to QGIS so maybe thats the reason why I cannot find anything on this on google (or is this due to the 2.8.1 compatebility issue?). My issue is that when ...
1
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2answers
19 views

Batch export QGIS for various locations

I have the data for several cities in a layer. I'd like to run a batch export, that goes through a list and zooms in on one city (coordinate + zoomlevel), then the next, etc and exports each results ...
2
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2answers
28 views

MMQGIS:Create:Hub Distance: Output shapefile in wrong coordinate system

I have a QGIS-project that is completely in EPSG:31467 - DHDN / Gauss-Kruger zone 3. It consists of random points (camera traps) surrounded by a polygon (forest edge). I already converted the polygon ...
0
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0answers
18 views

Thin black line get grey when using composite pattern

I have noticed a couple times that if I set pen width of line smaller than 0.20 the line is no longer black. It is clear that the line does not just look gray because it is thin, the line is changing ...
0
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0answers
13 views

Assign Nodes ID to Polylines in QGIS

I want to consolidate data from various layers into a single layer so I can export it for use in an external software program. I am interested in how to selectively combine data from different ...
1
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1answer
56 views

differences in distance between shapely and geopy

I am getting totally different distances from shapely and geopy. On one hand - it makes total sense, shapely measures on a plane and geopy measures on a spheroid. But the differences are so dramatic, ...
1
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1answer
39 views

Attribute table not updating after QGIS field calculator used? [on hold]

Using QGIS 2.8.1 i am trying to update an attribute table using the field calculator. its a vector layer of vegetation communities. i am trying to update the area fields in the table. The output ...
0
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0answers
30 views

QGIS - save vector poly layer into individual shp files? [duplicate]

Using QGIS v2.8.1, I have a directory of GeoTiff images. Using the raster ‘Tile Index’ plug-in (selecting “location” as the file index), I am able to create perfectly matched vector polys that I can ...
1
vote
1answer
31 views

Rename layers with script

Just discovered Qgis and really impressed! I've not formal GIS training so rely on Google to figure stuff out. I'm using the SHP files made available by the Canadian Government as part of their ...
5
votes
0answers
53 views

Getting weird lines in Print Composer QGIS

I am working with QGis 2.8 and want to use the print composer to create a jpg image. I used this PlugIn (https://github.com/jdugge/ClipToHemisphere) to create the globe. The graticules I created the ...
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0answers
33 views

Reproject before a Spatial Join

I have one polygon file containing all German municipalities as well as a point file. For each municipality, I would like to compute the average of a certain attribute of all points within the ...
0
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0answers
19 views

Georeferencer does not open when clicked

Since a week my raster georeferencer is not opening when I click it. I have made sure it is checked in the plugins collection and have tried re-installing the newest version of QGIS, yet also in this ...
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0answers
15 views

Difficulty creating a point layer using the line intersections function in QGIS [on hold]

I am attempting to create a point layer from two line layers where the lines cross. I am using QGIS's built-in Line Intersection tool but the output point file created remains empty. I have checked ...
2
votes
1answer
42 views

Merging ShapeFiles with QGIS for UK counties

I want to draw a map for all the counties of UK including North Ireland. Since I can not find a source of counties including both North Ireland and Britain. I try to merge two shapefiles with QGISfrom ...
1
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1answer
54 views

Where is the python library of QGIS 2.8

where is the Python library for QGIS 2.8 on a mac (10.10)? I cannot find it... sys.path in the QGIS python console gave me some path, but where the interesting part is happening it replaces the ...
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0answers
32 views

Representing overlapping polylines in QGIS

I have several shapefiles representing bus lines with different colors for each segment, however, because the lines are exactly superposed, only the shapefile on top can be seen. Is there a way to ...
1
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1answer
36 views

Proof low deviations in DEM compared to point dataset

I am not sure how to achieve the following consistently: I have a regular distributed point dataset (surface elevations). From this I derived several DEM using QGIS IDW Interpolation method. Now I ...