init

Author: rot1024

.github/workflows/ci.yml

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+name: CI
+on:
+  workflow_call:
+  push:
+    branches:
+      - main
+  pull_request:
+jobs:
+  ci:
+    name: CI
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+      - uses: golangci/golangci-lint-action@v6
+        with:
+          version: v1.64
+          skip-cache: true
+      - name: test
+        run: go test ./... -v -race -coverprofile=coverage.txt -covermode=atomic
+      - name: Send coverage report
+        uses: codecov/codecov-action@v4
+        with:
+          file: coverage.txt

.gitignore

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+*.asc

LICENSE

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+MIT License
+
+Copyright (c) 2025 Eukarya
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# japangeoid-go
+
+日本のジオイド高を計算するための Go ライブラリ / Go library for calculating geoid height in Japan
+
+- 本ライブラリは国土地理院が提供するものではありません。
+- 本ライブラリは [ciscorn/japan-geoid](https://github.com/ciscorn/japan-geoid/tree/main) （MIT License）を参考に実装しています。
+
+対応ジオイドモデル：
+
+- 日本のジオイド 2011（Ver.2.2）（[出典](https://fgd.gsi.go.jp/download/geoid.php)）: `gsigeoid2011`
+- 日本のジオイド 2025（[出典](https://www.gsi.go.jp/buturisokuchi/grageo_reference.html)）: 正式公開後対応予定
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/eukarya-inc/japan-geoid-go/gsigeoid2011"
+)
+
+func Example() {
+	g, err := gsigeoid2011.Load()
+	if err != nil {
+		panic(err)
+	}
+
+	lng, lat := 138.2839817085188, 37.12378643088312
+	height := g.GetHeight(lng, lat)
+	fmt.Printf("Input: (lng: %.6f, lat: %.6f) -> Geoid height: %.6f\n", lng, lat, height)
+
+	lng, lat = 10, 10
+	height = g.GetHeight(lng, lat)
+	fmt.Printf("Input: (lng: %.6f, lat: %.6f) -> Geoid height: %.6f\n", lng, lat, height)
+
+	// Output:
+	// Input: (lng: 138.283982, lat: 37.123786) -> Geoid height: 39.473871
+	// Input: (lng: 10.000000, lat: 10.000000) -> Geoid height: NaN
+}
+```
+
+## Lisence
+
+[MIT Lisence](LICENSE)

cmd/conv.go

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+package main
+
+import (
+	"compress/gzip"
+	"io"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+
+	japangeoid "github.com/eukarya-inc/japan-geoid-go"
+)
+
+func main() {
+	if len(os.Args) < 2 {
+		println("Usage: conv <file>")
+		os.Exit(1)
+	}
+
+	p := os.Args[1]
+	name := path.Base(p)
+
+	f, err := loadAsc(p)
+	if err != nil {
+		println(err.Error())
+		os.Exit(1)
+	}
+
+	defer f.Close()
+
+	grid, err := japangeoid.FromAsc(f)
+	if err != nil {
+		println(err.Error())
+		os.Exit(1)
+	}
+
+	f2, err := os.Create(strings.TrimSuffix(name, ".asc") + ".bin.gz")
+	if err != nil {
+		println(err.Error())
+		os.Exit(1)
+	}
+
+	defer f2.Close()
+
+	w := gzip.NewWriter(f2)
+	defer w.Close()
+
+	if err := grid.ToBinary(w); err != nil {
+		println(err.Error())
+		os.Exit(1)
+	}
+
+	println("Done")
+}
+
+func loadAsc(url string) (io.ReadCloser, error) {
+	if strings.HasPrefix(url, "http://") || strings.HasPrefix(url, "https://") {
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			return nil, err
+		}
+
+		res, err := http.DefaultClient.Do(req)
+		if err != nil {
+			return nil, err
+		}
+
+		return res.Body, nil
+	}
+
+	return os.Open(url)
+}

geoid2011/geoid2011.go

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+package gsigeoid2011
+
+import (
+	"bytes"
+	"compress/gzip"
+	_ "embed"
+	"fmt"
+
+	japangeoid "github.com/eukarya-inc/japan-geoid-go"
+)
+
+//go:embed gsigeo2011_ver2_2.bin.gz
+var geoid2011raw []byte
+
+func Load() (*japangeoid.MemoryGrid, error) {
+	b := bytes.NewReader(geoid2011raw)
+	g, err := gzip.NewReader(b)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create gzip reader: %w", err)
+	}
+
+	return japangeoid.FromBinary(g)
+}

geoid2011/geoid2011_test.go

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+package gsigeoid2011
+
+import (
+	"fmt"
+	// "github.com/eukarya-inc/japan-geoid-go/gsigeoid2011"
+)
+
+func Example() {
+	g, err := Load()
+	// g, err := gsigeoid2011.Load()
+	if err != nil {
+		panic(err)
+	}
+
+	lng, lat := 138.2839817085188, 37.12378643088312
+	height := g.GetHeight(lng, lat)
+	fmt.Printf("Input: (lng: %.6f, lat: %.6f) -> Geoid height: %.6f\n", lng, lat, height)
+
+	lng, lat = 10, 10
+	height = g.GetHeight(lng, lat)
+	fmt.Printf("Input: (lng: %.6f, lat: %.6f) -> Geoid height: %.6f\n", lng, lat, height)
+
+	// Output:
+	// Input: (lng: 138.283982, lat: 37.123786) -> Geoid height: 39.473871
+	// Input: (lng: 10.000000, lat: 10.000000) -> Geoid height: NaN
+}

geoid2011/gsigeo2011_ver2_2.bin.gz

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+package japangeoid
+
+// GridInfo はジオイドモデルのメタデータを表します。
+type GridInfo struct {
+	XNum    uint32  // x方向グリッド数
+	YNum    uint32  // y方向グリッド数
+	XDenom  uint32  // x方向の分母 (0.025→1/0.025=40)
+	YDenom  uint32  // y方向の分母 (0.016667→1/0.016667≈60)
+	XMin    float32 // 経度の最小値
+	YMin    float32 // 緯度の最小値
+	IKind   uint16  // 未使用(ヘッダのikind)
+	Version string  // バージョン文字列
+}

gird_info.go

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+module github.com/eukarya-inc/japan-geoid-go
+
+go 1.24.0