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I just downloaded QGIS (3.0.2) and trying to create minimum convex polygon around points using minimum bounding geometry (convex hull). The videos and help documents I see online appear to be from older editions of QGIS. I cannot find comparable menu options in this edition.

Can this be done in this version of QGIS?

If so, I seek simple instructions (I'm new to GIS).

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I had no problem with the convex hull (vector > geoprocessing tools > convex hull) of QGIS 2. It used to make a convex hull around a set of points immediately. In QGIS 3, the same raises the error "Cannot calculate convex hull for a single Point feature (try 'Minimum bounding geometry' algorithm instead)."

Greg gave the answer (toolbox -> Vector Geometry -> Minimum Bounding Geometry): enter image description here

In the drop box "Geometry type", choose "Convex hull".

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Thank you for the quick response. It was helpful. But I am still not getting what I expected. My goal is for QGIS to create a polygon around the outermost points - a minimum convex polygon. This is done in ArcMap by using minimum bounding tool with convex hull geometry. My impression is the instructions you give above is the QGIS equivalent. These images show you what I am doing and then what I get. I get a new 'layer' entitled convex hulls but they are not showing anything. I zoom to layer and nothing; I turn off all other layers and I get a completely white canvas. I checked the projection (all are in UTMs) and that is correct. Any thoughts? What I need is a single polygon connecting the 'outer' dots. But I am trying to do this for research so I do not want to connect dots by manually drawing a polygon - that is too subjective for peer-review. Thank you in advance.

enter image description here

enter image description here

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I read this earlier when trying to make an MCP myself. In QGIS 3.2.0-Bonn, I made a 100% MCP by opening the processing toolbox -> Vector Geometry -> Minimum Bounding Geometry.

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Welcome to GIS StackExchange! Try the Vector menu as shown below:

enter image description here

  • Processing toolbox-concave hull will solve your problem. – Rashmita Sep 12 at 9:58
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Interesting. I tried to reproduce your problem and I have the exact same problem. So I assume that it has something to do with QGIS 3.0.x

If you know your way around R, there is a great package for home range analysis called "adehabitatHR". It provides various functions for HR analysis, some a lot more sophisticated than convex hulls.

https://cran.r-project.org/web/packages/adehabitatHR/vignettes/adehabitatHR.pdf

hope this helps

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First, you want to add a new field to your point data that represents which polygon the points belong to. Remove the blank rows that represent the spaces between your polygons.sample point data

Next, use the vector geometry tool called minimum bounding geometry that @Greg suggested, but make sure you set the "Field" to your new polygon field.min bounding box tool window

Points before: points

Polygons after: enter image description here

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