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Comment by imgabe | Hacker News Reader

This looks promising. I hope they add some way to measure distances.

What I'm currently wanting to do is draw a circle that's e.g. 100 meters around a given latitude and longitude. Google maps doesn't let you do this. I could do it with Leaflet, but that would involve setting up a whole js app for something that is basically just a back of the envelope calculation. I have access to ArcGIS which I'm sure can do it, I guess I'll have to learn how to use it.

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Funny thing is, it's not exactly a back of the envelope calc, as technically speaking it depends on your requirements on accuracy (or rather, your tolerance for different flavours of distortion), the projection you wish to draw in, the projection the measurement is done in, and what tradeoffs you are willing to make on circumference/shape/area.

Also factors: where you draw the circle, because this matters depending on your choices of projections.

ArcGIS or GDAL or whatever can do the math for you, but there's still domain knowledge and careful tradeoffs involved in representing anything spatial and meeting actual IRL need. It's all relative (and a bit of a goddamned nightmare)

(src: I used to build spatial tools on ArcGIS)

It's coming soon!

I use Free Map Tools for things like this. It's a bit rough around the edges, but does the trick.

https://www.freemaptools.com/

You can do that in Caltopo. They have a lot of really handy mapmaking features (like viewsheds and their “measure distance” tool that can snap to roads and trails), though their UI leaves a lot to be desired.

You can do this quite easily using the ST_Buffer function in PostGIS.

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