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

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167 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 ...
0
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1answer
77 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
27 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
67 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
32 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
27 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. ...
4
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1answer
94 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
38 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
78 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
44 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
116 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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2answers
145 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 ...
0
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0answers
77 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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3answers
135 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
votes
2answers
48 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
62 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
66 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
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1answer
165 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, ...
2
votes
2answers
78 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
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1answer
47 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
46 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 ...
2
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0answers
73 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, ...
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0answers
26 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 ...
2
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2answers
47 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
61 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 ...
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0answers
20 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 ...
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0answers
23 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
143 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
84 views

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

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
31 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
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1answer
62 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 ...
6
votes
1answer
121 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
51 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 ...
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0answers
28 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 ...
2
votes
1answer
79 views

Merging ShapeFiles with QGIS for UK counties

I want to draw a map for all the counties of the UK including Northern Ireland. Since I cannot find a source of counties including both Northern Ireland and Britain, I tried to merge two shapefiles ...
1
vote
1answer
181 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 ...
3
votes
1answer
123 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
49 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 ...
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0answers
51 views

3d model to point cloud

Excepting FME, is there a way to convert 3d model to point cloud?
0
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0answers
32 views

Graduated Style on edges not appearing — QGIS

I have added a layer from a PostGIS database. The layer is representative of road segments in the greater Chicago area. I have added a second layer that does not have any geometry information but ...
0
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0answers
74 views

develop rooftop solar radiation potential from 3d buildings model (3dm)

Need to create solar cadastre without having LIDAR data. Have 3d buildings model in .3dm (150 000+ roof surfaces, 500 000+ facade surfaces unmapped, dtm 15x15m) with a lot of multipatch geometry ...
0
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0answers
56 views

Convert Zip+4 to Lat-Long

I have a need to convert about 1 million Zip+4 records to Latitude/Longitude for mapping but cannot find anything that is granular enough in output. Is there an easy way to convert this information?
4
votes
1answer
210 views

Programmatically grouping multiple layers into separate groups using QGIS?

I'm trying to group a large number of layers together based on a common portion of name string. They are a mix of polygons and points. I would like to create individual groups by using part of the ...
0
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0answers
56 views

force QGIS-labels behind polygon areas

Is it possible to force labels behind a polygon dataset. In my case I want to put 50% transparent polygons onto areas, which are shown "inactive" on maps. Unfortunately, some feature labels are shown ...
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0answers
50 views

dxf-Export is not readable in BricsCad

With the QGIS 2.8 dxf-Export it is not possible to open these files in BricsCad (a CAD-Programm which is very similar to AutoCad). the dxf-Export from GIS 2.8 and import in BricsCad looks like!(not ...
0
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0answers
51 views

Using the phase 1 habitat styles?

I am utilising the phase 1 habitat styles and wanted to show 'mixed scattered trees' which is essentially a layer with two different types of green dot. I cannot figure out how to do this and also ...
1
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1answer
56 views

extracting the outline of raster imagery using GDAL

Salams I want some help regarding developing a method using GDAL to extract and represent the footprint of any raster file (or group of raster data) in a vector format... any ideas please ??
0
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1answer
42 views

Graphical modeler in QGIS. I can't find a model [duplicate]

I'm a doing a tutorial for QGIS and at one point I have to use 'Join attributes by location' model but I do not find it in the Graphical modeler. Does it have to be there? I have to download it from ...
1
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0answers
189 views

qgis-bin.exe - System Error

I'm running QGIS 2.8 Wien on Windows 8.1. I got this error: The program can't start because qgis_core.dll is missing from your computer. Try reinstalling the program to fix this problem. I ...
2
votes
2answers
88 views

QGIS distance matrix: wrong metric distance

I used the lineair distance matrix tool in QGIS 2.6 My coordination system is metric (national Dutch RD new) The results have the wrong decimals, as shown below. How can I fix this? (showing unique ...