Add faces, distance and miscellaneous functions

[retbrown]

Add functions to cover all functions in the current version of H3 except the two experimental prefixed functions (experimentalH3ToLocalIj and experimentalLocalIjToH3)

At a minimum it covers the functions mentioned in #29 and #44

[coveralls]

Pull Request Test Coverage Report for Build 617809629

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

---

Totals
Change from base Build 611964428:	0.0%
Covered Lines:	278
Relevant Lines:	278

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💛 - Coveralls

[phanirithvij]

I think you can remove #45 from this PR's description. I'd also like to know when this will be reviewed/merged?

[phanirithvij]

Also, this code is giving me all 0s when using your fork, all the three ExactEdgeLength.. methods give 0

package main

import (
    "fmt"

    "github.com/uber/h3-go/v3"
)

func main() {
    pt := h3.GeoCoord{
        Latitude:  38.8935128,
        Longitude: -77.1546608,
    }
    for i := 0; i < 16; i++ {
        h := h3.FromGeo(pt, i)
        fmt.Println(h3.ExactEdgeLengthRads(h), h3.ExactEdgeLengthKm(h), h3.ExactEdgeLengthM(h))
    }
}

I'm running it with a go.mod setup like this

module example.org/server

go 1.16

replace github.com/uber/h3-go/v3 => github.com/retbrown/h3-go/v3 v3.0.3-0.20210303141742-f0831fcf37f8

require github.com/uber/h3-go/v3 v3.7.0

Should I open a new issue here, after this gets merged?

I didn't try out the C implementation because I'm assuming it's hard to set it up on windows. I will open an issue over at the h3 repo after trying it out on my Linux machine

[retbrown]

The ExactEdgeLength* methods all require an edge index rather than a cell index. So rather than just passing the h3 index you would need to pass the index for one of the edges. I have modified your code above to do that below. You would need an additional call to ToUnidirectionalEdges and in the example i have just used the first entry in the returned slice to calculate the length from.

package main

import (
    "fmt"

    "github.com/uber/h3-go/v3"
)

func main() {
    pt := h3.GeoCoord{
        Latitude:  38.8935128,
        Longitude: -77.1546608,
    }
    for i := 0; i < 16; i++ {
        h := h3.FromGeo(pt, i)
        fmt.Println(h3.ExactEdgeLengthRads(h3.ToUnidirectionalEdges(h)[0]), h3.ExactEdgeLengthKm(h3.ToUnidirectionalEdges(h)[0]), h3.ExactEdgeLengthM(h3.ToUnidirectionalEdges(h)[0]))
    }
}

Outputs

$ go run main.go
0.1907659917703397 1215.371503443869 1.215371503443869e+06
0.07426317049993154 473.1311925328369 473131.1925328369
0.02893347635775318 184.33538564418043 184335.38564418044
0.010826730357448312 68.97717685317124 68977.17685317124
0.004167017952265829 26.548101296901795 26548.101296901794
0.0015478829104757237 9.861573137861825 9861.573137861826
0.000595086120136727 3.7912979446560024 3791.2979446560025
0.00022113288344402618 1.408839188359099 1408.839188359099
8.503464557269192e-05 0.5417563375704776 541.7563375704776
3.159208403445066e-05 0.20127339424366508 201.27339424366508
1.2148338271555708e-05 0.07739715036430815 77.39715036430815
4.513240645524859e-06 0.02875388856185201 28.753888561852012
1.7354751499254653e-06 0.011056724642480706 11.056724642480706
6.447497860535891e-07 0.004107705516843067 4.107705516843067
2.47925020279934e-07 0.0015795320845328183 1.5795320845328182
9.210711662312412e-08 0.0005868151014196192 0.5868151014196192

[phanirithvij]

@retbrown can this be merged?

[retbrown]

Hi @phanirithvij, Sadly I don't have permissions on the repo to merge any code