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168 views

How to get the coordinates inside the polygon using python

I have a polygon and using this code snippet we can get the coordinates boundary of the polygon. canvas = qgis.utils.iface.mapCanvas() aLayer = canvas.currentLayer() coord = ...
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52 views

Nearest neighbour / spatial join with attribute condition

I have 2 point format datasets I wish to schematically join (manholes & gullies). I am content that I can join them by nearest proximity alone using e.g. NNJoin plugin. What I would like to do ...
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1answer
171 views

Does anyone know a way to do a supervised classification on a google maps image to show only hedgerows? [closed]

I would like to then use the hedgerows by bringing it into QGIS as a layer. I need to know what software to use and the method to make such a layer? I would like to use a google earth image in Grass ...
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3answers
188 views

Processing modeler: how to dissolve a vector layer and sum the attributes

I have a complex workflow prepared in the processing modeler, but I'm missing one step to link all the model. I need to dissolve a polyline vector in a single line vector that has as attribute the ...
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2answers
178 views

Suitable Raster processing methods to extract field boundaries from images

I'm trying to extract field boundaries and features from a lot of aerial images of agricultural land - and avoid digitizing these features manually. I've managed to get a crude raster file of the ...
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2answers
261 views

Running LAStools on QGIS 2.8: “missing dependency. lastools folder is not configured”

To be honest I'm not sure how to run LAStools from within QGIS 2.8. I'm trying to learn by experimentation. QGIS shows all the LAStools in the toolbox If I double click on a LAStool in the toolbox I ...
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1answer
134 views

Using GDAL library in QGIS plugin?

i've been working on my project to create QGIS plugin for raster analysis purpose. It will be easier if we use gdal library. Are we able to use gdal library to develop QGIS plugin? If so, how do ...
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0answers
30 views

How to pass a token value to QGIS processing modeler?

There are various places in the Processing modeler where I would like to pass the value of a variable. We're iterating through a bunch of features in an input layer. After the processing, we will have ...
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32 views

Couldn't load plugin sextantelwgeomprovider, QGIS 2.0.1 on Ubuntu 14.04.2

I'm getting this error message when I start QGIS Couldn't load plugin sextantelwgeomprovider due an error when calling its classFactory() method Traceback (most recent call last): File ...
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1answer
227 views

What's difference between Topology and Check Validity in QGIS?

I would like to know what the difference is between the Topology Checker and Check Validity tools? Is there anyone who knows of a good document or tutorial that explains functions of these tools? ...
3
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1answer
69 views

Dependent Comboboxes in QGIS 2.8.2

I´m setting up an database for an archaeological project with PSQL. There I have a field "material" connected with a table "materials" containing things like metal, stone, etc. In a third table I have ...
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1answer
140 views

How can I create a polygon from points and assign it a color in QGIS using python?

I want to create a new vector layer, containing a polygon from a set of given points, and giving it a color.
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43 views

Is it possible to perform spatial join in PostGIS and keep all features?

I am attempting to create an employment change map using a hex grid. I have individual establishment data as points with attached employment figures. When I ran the spatial join using the postGIS ...
3
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1answer
49 views

QGIS Convert bathymetry shapefile from fillable to strokeable

In Java I would like to stroke the bathymetry depth lines instead of filling the area. I'm starting with the Natural Earth Bathymetric Data: ...
2
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1answer
359 views

Grass 7 no longer works via the Processing Toolbox on Ubuntu

When I try to execute a Grass 7 algorithm via the Processing Toolbox in QGIS 2.10, 2.8.2 or 2.8.1, I get the following error: Missing dependency. This algorithm cannot be run :-( QGIS ...
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3answers
137 views

How do I count the number of vector lines that pass though a given raster cell?

I am working on a project (currently in GRASS7 though I'm not against exporting to Arc or R or other software if necessary) where I am generating thousands of shortest cost paths (using the r.walk and ...
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0answers
412 views

Minidump Error Messages With Large Dataset

I'm using QGIS 2.8 on a system running Windows 8.1 (x64) with 12GB of RAM. I am attempting to run analyses of a very large database (.gdb format, 7.17GB). In attempting to run the "Join attributes by ...
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2answers
151 views

Pipeline connectivity

I'm trying to find a way to determine pipeline connections located downstream a critical facility and score how far those connections are from the facility. Any Thoughts?
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3answers
128 views

QGIS 2.2 is very slow while saving the edited layers

I am using QGIS 2.2 64 bit in windows 7 system. I have an issue while saving the layers after editing. Its taking more time to save my edits. Some times it's working fine but very often i am getting ...
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1answer
151 views

QGIS Composer: Force loading of all tiles on export

I face the problem that not all tiles are loaded on a map export via the QGIS composer. This happens randomly with all kinds of tile servers provided by the openlayers-plugin. Any hint how I can ...
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1answer
51 views

Shape Files and adding Label Data

Introduction: I'm still fairly new to GIS and have only had about 3 weeks experience. I set up an OSM server locally with .osm.pbf data and it worked just fine. When I pulled the map in the browser, ...
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2answers
414 views

Importing raster adf files with the additional files

I am trying to import a vegetation data raster in Esri GRID format from the USDA into QGIS. One file ("w0001.adf") can be added using "add raster", but the attribute table and other info register as ...
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1answer
107 views

QGIS models. deleting multiple columns is slow, is there a better way?

I have a process that has lots of items. This for some reason seems to make a difference to the time it takes to drop a column from a shape file during a model run. i need to drop MANY columns. QGIS ...
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76 views

cutting donuts in qgis

Im trying to cut donut polygons ready to go into a system that cant display them. Basically the exact opposite of this post: How to convert fake donut holes in polygons to real ones? I want to cut ...
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2answers
308 views

How to convert CSV file in VRT

Im a geomatics student. For the treatment I would like to make, I use the gdal executable in QGIS file, with a DOS command. I have a csv file like this (test.csv) : X Y -5.48 42.81 -4.78 ...
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0answers
140 views

Using GEOJSON offline in QGIS

I have some GEOJSON-Layers in my QGIS-project. The problem is, that when I zoom in or out, it takes very long to built up the window again. That's because it always loads it from the server. But I ...
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1answer
204 views

Big performance difference reading shapefiles between QGIS and R

I'm trying to read the belgian landuse ESRI shapefile from geofabrik.de: http://download.geofabrik.de/europe/belgium.html In QGIS it's just a matter of seconds, but in R using the readOGR function ...
3
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1answer
78 views

Moving cursor using PyQGIS?

I would like to move the cursor to a given x,y coordinates of the MapCanvas. Is there an easy way to do this using PyQGIS?
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125 views

Generating shapefile of polylines using pyshp from a csv file and opening file in qgis

I tried the solution posted in: Creating Polyline from GML using PyShp?, Using PyShp to convert polygons in *.csv to *.shp files? and Using PyShp to create polygon shapefiles? to generate ...
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0answers
138 views

How to speed up simultaneous working with PostGIS layers in QGIS?

we are working on one big layer at the same time (10-20 people). Some of us use QGIS 2.8.1 and the other 2.6. The user with 2.8 have a lot of crashes (QGIS). The 2.6 users don't have this crashes but ...
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0answers
112 views

How to create multiple polyline transects with a certain orientation?

I am attempting to create multiple polyline transects and use them as cross-section profiles to analyze snow drifts on a landscape. Is there a method of creating multiple transects in such a way that ...
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26 views

Is it possible update a shapefile instead create a new one when using Processing?

Using Processing to add or calculate a field it's always necessary create a new shapefile? Is there a way to just update and keep using same layer?
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94 views

QGIS Training Manual - Lesson 12.2.1 (GRASS GIS) - r.colors.table module does not color raster

I am going through the QGIS Training Manual, Lesson 12.2.1 ("Follow Along: Set Raster Colors) and noticed that the 'r.colors.table' GRASS module did not color my DEM raster layer which I imported via ...
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1answer
163 views

Grid vs. Polygon Overlay in R gives different results than in QGIS

I have a shapefile of range polygons. Each colored set of polygons represents a different group of species/genera/whatever. I next overlay a 5x5 grid onto this map. And then use join attributes by ...
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324 views

Converting Points to Lines in QGIS using Points2One Plugin - generates attribute table but the lines are not visible

I am using the Points2One plug in (QGIS 2.6.0) to generate lines from points. There are 2 layers on which I have worked on. Point Layer 1: This was generated/created for testing purpose with fields ...
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31 views

Accessing SD card and/or cloud storage in QGIS android

Is there anyway to access the SD card or cloud storage in QGIS for android? I find that I will be running out of space on my tablet anytime soon as it seems everything has to be on the main device ...
2
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1answer
588 views

QGIS2WEB Plugin (openLayer3) for QGIS not exporting raster images

I am using the QGIS2WEB plugin for QGIS. I have added vector features as well as a raster image (.tif or .ecw) format. When I try to export the webmap, all the layers are visible expect the rasters. ...
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0answers
62 views

How can i add sub menu under custom top menu in QGIS using python

I have added "My Tools" Menu on top. Now i am clicking on "Plugin" then selecting QGIS Plugin bulider. Here in the menu field a drop down list is coming. How can i add "My tools" in this drop down ...
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0answers
166 views

qgis unable to connect to ms sql server using sql authentication

I am getting the following error when I try to set up a connection to a MS SQL Server database using sql server authentication. I did find a bug report from 2014, but that was apparently fixed and ...
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1answer
75 views

Capturing coordinates via snap with QGIS

I would like to know if there is a way to get and extract the coordinates of a node (one of the node that conforms a polygon) in order to use these pair of coordinates to georeference a DXF file, ...
1
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1answer
62 views

QGIS Attribution and Geometry Query Question

I am trying to use select by expression to query lines that contain certain attributes and that there geomerty touch. In other words are connected or neighbor each other. I tried a query such as ...
3
votes
2answers
64 views

QGIS: additional description in legend [duplicate]

In ArcMap there is the possibility to have a symbol, the symbol description or layer name and an additional description in your legend Layer Properties --> Symbology --> Fetaures: Single symbol --> ...
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2answers
86 views

What CRS is the USGS Global Land Cover Characteristics Data Base?

I have trouble bringing land cover data from the USGS into a "decent" coordinate system. I obtained an .img file of the "Global Land Cover Characteristics Data Base Version 2.0" from ...
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2answers
486 views

PopUp with Images with QGIS2web

is it possible to create popups with images via QGIS2web? if yes, what would be the workflow? Couldn't it figure out yet. So any help is welcome! Thanks
3
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0answers
35 views

Extract the outer points of a Point Shape into a Line Shape? [duplicate]

I've installed QGIS 2.8.2 since a few days and have no experience with this application. I try to extract the outer points of a Point Shape into a Line Shape, like a shell for the inner points. All ...
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2answers
146 views

Topological errors after dissolve - how to avoid/get rid of?

After dissolving a layer in QGIS 2.8, I get a lot of topological errors in the new (dissolved) layer. Any suggestions as to how to get rid of these errors without manually editing each one? ...
3
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0answers
75 views

Trouble importing an QGIS ascii DEM file

The output I get from QGIS 7.0.1 for an ASCII DEM file doesn't seem to be a correct format. It differs from the format I get when I download a DEM file from webGIS ( ...
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2answers
512 views

Is there a way of mirroring layers on QGIS?

I would like to know if there is any way of mirroring layers on QGIS. My current project is a bit hard to explain... I'm excavating the inside of a large pot and, in the end I will have a set of plans ...
4
votes
1answer
222 views

Generate grid shapefile in R

I have the following shapefile of a 10x10 degree latitude/longitude grid that I created in QGIS. I can read it into R using the rgdal package. Grid<-readOGR(".","GridShapeFile") It has the ...
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0answers
121 views

QGIS printing shift on WGS 84 Pseudo Mercator base

I've had this problem before but I'm not succeeding in fixing it using what I thought worked before. This has been brought up as an issue previously, but I'm stuck when I apply the previous answers. ...