Coordinates are stored as Floats. Could they also be integers? about geo

[amandasaurus]

My motivation for this was when working with the MVT vector tile format for OpenStreetMap. In that file format, vector geometry is stored as integers.

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the intersection of two integral line segments

Yes I had those problems. For my use case I just choose some point that's "good enough". the Intersection algoritm is probably one where you Floats are required.

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I do think a rasterize operation onto a given grid at the end is the way to go -- that way the user could provide whatever grid they wanted.

You can do this with the MapCoords trait, which allows you to change the types. You could convert f64 to i32 etc. (That's one of the reasons I wrote it like this.

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We should definitely explain what's going on in the docs, point out caveats etc. when this turns into a PR, though.

Agreed. I didn't do the "grunt work" in the fork because I wasn't sure if the idea was acceptable and likely to be merged. Now that I see the support, I'll work on cleaning it up and making a real PR.

[amandasaurus]

I have worked on this a little more, and reworked it against current master. The new branch is https://github.com/rory/rust-geo/tree/any-num-coordinates

Any feedback? Is this something that rust-geo should have?

[mbattifarano]

Would you mind pushing the branch? I'm curious to take a look. I don't think I understand how this would work since many operations on integral geometries won't always return integral geometries.

For example, the intersection of two integral line segments: l1 = (0, 0), (2, 1) and l2 = (0, 1), (1, 0) is (2/3, 1/3). Walking through the algorithm with ints (and integer division) you'd get (0,0) (or one of the other endpoints depending on the implementation).

At first glance, I do think a rasterize operation onto a given grid at the end is the way to go -- that way the user could provide whatever grid they wanted.

[amandasaurus]

There's a branch here: https://github.com/rory/rust-geo/tree/any-num

This commit is how I implemented it. I created CoordinateType to replace the Float. Then it's almost just a find and replace to use that instead.

Some operations (like line intersection or area) might not make sense, and still require the Float trait.

[jdroenner]

I like it. Operations can still limit the generic type to Float if they require it.

[frewsxcv]

yep, looks good to me too 👍

[urschrei]

I don't do much raster stuff atm so I'm not really qualified, but it definitely seems like a good idea. We should definitely explain what's going on in the docs, point out caveats etc. when this turns into a PR, though.

[amandasaurus]

PR #187 fixes this, so I'll close the issue. Discussion should take place on the PR