latlng.go

// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package maps

import (
	"math"
	"strconv"
	"strings"
)

// LatLng represents a location on the Earth.
type LatLng struct {
	Lat float64 `json:"lat"`
	Lng float64 `json:"lng"`
}

// ParseLatLng will parse a string representation of a Lat,Lng pair.
func ParseLatLng(location string) (LatLng, error) {
	l := strings.Split(location, ",")
	lat, err := strconv.ParseFloat(l[0], 64)
	if err != nil {
		return LatLng{}, err
	}
	lng, err := strconv.ParseFloat(l[1], 64)
	if err != nil {
		return LatLng{}, err
	}
	return LatLng{Lat: lat, Lng: lng}, nil
}

// ParseLatLngList will parse a string of | separated Lat,Lng pairs.
func ParseLatLngList(locations string) ([]LatLng, error) {
	result := []LatLng{}

	ls := strings.Split(locations, "|")
	for _, l := range ls {
		ll, err := ParseLatLng(l)
		if err != nil {
			return []LatLng{}, err
		}
		result = append(result, ll)
	}
	return result, nil
}

func (l *LatLng) String() string {
	return strconv.FormatFloat(l.Lat, 'f', -1, 64) +
		"," +
		strconv.FormatFloat(l.Lng, 'f', -1, 64)
}

// AlmostEqual returns whether this LatLng is almost equal (below epsilon) to
// the other LatLng.
func (l *LatLng) AlmostEqual(other *LatLng, epsilon float64) bool {
	return math.Abs(l.Lat-other.Lat) < epsilon && math.Abs(l.Lng-other.Lng) < epsilon
}

// LatLngBounds represents a bounded square area on the Earth.
type LatLngBounds struct {
	NorthEast LatLng `json:"northeast"`
	SouthWest LatLng `json:"southwest"`
}

func (b *LatLngBounds) String() string {
	return b.SouthWest.String() + "|" + b.NorthEast.String()
}