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I have a point layer in QGIS in EPSG:4326 and want to create polygon-circles of 10m radius around each point. All of the points are located within a kilometer² in northern Germany. How do I do this? Buffering generates circles which are ellipses and way too big.

I'm quite inexperienced with GIS and I honestly searched the old questions before I posted this.

Taras
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Chris
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    Please define what you mean by "buffering doesn't seem to work". Which CRS is your point layer in? – Erik Oct 02 '20 at 10:01
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    Following on from @Erik, when you try to buffer does it result in polygons that are way too big or does it fail to even run? If it fails then what error does it throw? The CRS (Coordinate Reference System) of your data needs to be in metres if you want to buffer it by x metres, data can usually be reprojected easily so if it isn't in the correct CRS then it's fixable. – TeddyTedTed Oct 02 '20 at 10:16
  • Thank you for answering! The CRS is EPSG:4326 (if that makes any sense), and when I buffer the "circles" are neither circle shaped nor the right size (way too big). That might be because the CRS is not in meters... – Chris Oct 02 '20 at 10:31
  • This is a duplicate of many questions, for example https://gis.stackexchange.com/questions/67775/why-does-the-buffer-take-up-whole-screen and https://gis.stackexchange.com/questions/118248/create-buffer-to-qgis but it is understandable that it surprises new users. – user30184 Oct 02 '20 at 11:48
  • Does this answer your question? Buffering in meters/km using WGS84 layers using QGIS – til_b Oct 02 '20 at 11:54
  • Thank you all for your help! The question is answered and it worked! – Chris Oct 02 '20 at 11:56
  • Please, do not forget about "What should I do when someone answers my question?" – Taras Jan 21 '22 at 12:11

2 Answers2

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From your comment your data is in EPSG 4326 which is WGS 84, this uses latitude and longitude coordinates, so when you tell that to buffer by 10 it buffers by 10 degrees which is massive.

To get your point layer to use metres instead you will need to convert it to a CRS which uses metres. You will need to right click on the layer in the table of contents, then Export > Save Features As and as part of saving them choose an appropriate CRS. Choosing the right CRS depends on where in the world your data is. Google is your friend here to find out what's the right CRS.

This new dataset should now buffer correctly.

TeddyTedTed
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    Good answer. Since the OP says all his points are within 1 sq km in Germany, any projected CRS that works well in Germany will work for them, and give essentially identical results for a 10m buffer. EPSG:5243 is one that they can use if no-one else is prescribing other guidance. – Houska Oct 02 '20 at 10:51
  • Thanks @Houska, I'm not familiar with CRSs for Germany so I was hesitant to recomment any. TIL EPSG:5243 is the way to go. – TeddyTedTed Oct 02 '20 at 11:00
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    Usually we're using 25832 (UTM 32N) and 25833 (33N). This is supported by next to all official sources. – Erik Oct 02 '20 at 11:03
  • Thank you so much guys, it worked! – Chris Oct 02 '20 at 11:30
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    Please mark it as the answer if it did the job. – MarcM Oct 02 '20 at 12:18
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I see that there is an answer here that probably should have been accepted, but just an extra comment.

It depends a bit on what you want the 10m circles for. If you want to use them for some further geographical analysis, you need to reproject your data and do the buffering as mentioned above. On the other hand, if you want them just for displaying on the map, in the Layer properties -> Symbology, set your marker as 10 "Meters at scale" with a transparent fill color. Add on another marker if you want to mark the centre point.

This gives a cross surrounded by a circle of 10 meters Setup of symbology

Zoomed in Zoomed in

Zoomed out Zoomed out

Notice that the size of the cross on the image does not change. If zoomed out far enough the circle will not be visible.

MortenSickel
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