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1500 questions
27
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7 answers

Transferring custom QGIS settings from one computer to another?

Can I export custom general settings from my QGIS installation to a file so that I can transfer the settings to QGIS on a different computer? Does QGIS have them already saved to a file located somewhere on hard disk?
Guest25
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27
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3 answers

Get Lon Lat values from a GEOGRAPHY data type in PostGIS

After storing lon lat values as a GEOGRAPHY data type, how do I retrieve the individual lat lon values? Failed attempt: SELECT id, geog, ST_X(geog), ST_Y(geog) FROM locations; Error: No function matches the given name and argument types. You might…
Nyxynyx
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27
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3 answers

Reading attribute values using PyQGIS

What is the way to get the information contained in the attribute table, say in column 2, row 2 using PyQGIS?
user16018
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27
votes
3 answers

Are ellipsoids a mathematical necessity?

The literature usually just tells us that the Geoid is too complex to describe mathematically and that we therefore fit different Ellipsoids to approximate it. Are these Ellipsoids mathematically necessary, or could we define projections from the…
underdark
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27
votes
4 answers

The simplest way to uninstall any and all ArcGIS products?

What it is the simplest and most straightforward way to uninstall any and all ArcGIS products more or less in one go that might be present on a Windows machine? perhaps scriptable? Add/Remove Programs from the Control Panel is straightforward, but…
matt wilkie
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27
votes
6 answers

What tools in Python are available for doing great circle distance + line creation?

I need to use Python to create a great circle distance -- both a number, and preferably some kind of 'curve' that I can use to draw in a client-side map. I don't care about the format of the curve -- be it WKT, or a set of pairs of coordinates --…
Christopher Schmidt
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27
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5 answers

Is ArcSDE no longer needed at ArcGIS 10.1?

Through my frustration of not finding the post-installation wizard with ArcSDE 10.1 and being unsuccessful with the command line tool to start an SDE service on our SDE databases, I found I was able to access the databases and copy/past/add…
Luke
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27
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5 answers

Getting path of project or layer file in PyQGIS

I am generating new raster files from vector layers on a project. I would like to save them in the same directory as the project or layer files. How do I find this path using PyQGIS?
fccoelho
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27
votes
6 answers

Finding centrelines from polygons in QGIS

I was wondering if there is a way to create center lines from polygons in QGIS? I have a polygon layer, but ideally need the centerlines as a separate file.
Alan Carr
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27
votes
5 answers

Error adding qgis.org repository public key to apt keyring

The old QGIS key ring qgis-2017.gpg.key is expired and generates a warning during apt update today. Following the QGIS instructions, I tried to update the key as follows: wget -O - https://qgis.org/downloads/qgis-2019.gpg.key | gpg --import gpg…
tinlyx
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27
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4 answers

Counting number of vertices of polygons and lines in QGIS?

In QGIS, is there a way to count the number of vertices of polygons and lines in a given layer, and create a separate field containing these values? I suspect it's a function somewhere in the field calculator but I can't find it.
crichard75
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27
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12 answers

Working with LiDAR data using other than Esri software?

I will be working with LiDAR data soon and I am wondering what the alternatives to using Esri software to do this are, including open source solutions?
Robert Buckley
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27
votes
7 answers

Drawing Circles with set radius using QGIS

I have a site and want to draw an indicative line in a 5km buffer around the centre of the site. So I want to draw a circle with a radius of 5km. I have a tool for drawing circles and ellipses and rectangles squares and spirals. None of these let me…
Ger
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27
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4 answers

Calculating distortion on Equirectangular Projection

I am trying to calculate distortion so I can distort overlaying text and forms to precisely match an image of an equirectangular projection. How does one calculate the distortion at a given latitude on an equirectangular projection 1:45,000,000…
NCashew
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27
votes
2 answers

Using QGIS vertex editor?

I'm having two main problems: When hovering over a map with multiple layers, even though I only have one layer editable and visible, I am seeing all the nodes of all layers show up as red dots when hovering over the map canvas, making it impossible…
John N
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