Add Elevation API

elevation.go

@@ -0,0 +1,73 @@
+package maps
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func (c Client) Elevation(ll []LatLng) (*ElevationResponse, error) {
+	var r ElevationResponse
+	if err := c.doDecode(baseURL+elevation(ll), &r); err != nil {
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (c Client) ElevationPolyline(p string) (*ElevationResponse, error) {
+	var r ElevationResponse
+	if err := c.doDecode(baseURL+elevationpoly(p), &r); err != nil {
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (c Client) ElevationPath(ll []LatLng, samples int) (*ElevationResponse, error) {
+	var r ElevationResponse
+	if err := c.doDecode(baseURL+elevationpath(ll, samples), &r); err != nil {
+		return nil, err
+	}
+	return &r, nil
+}
+
+func (c Client) ElevationPathPoly(p string, samples int) (*ElevationResponse, error) {
+	var r ElevationResponse
+	if err := c.doDecode(baseURL+elevationpathpoly(p, samples), &r); err != nil {
+		return nil, err
+	}
+	return &r, nil
+}
+
+func elevation(ll []LatLng) string {
+	p := url.Values{}
+	p.Set("locations", encodeLatLngs(ll))
+	return "elevation/json?" + p.Encode()
+}
+
+func elevationpoly(poly string) string {
+	p := url.Values{}
+	p.Set("locations", "enc:"+poly)
+	return "elevation/json?" + p.Encode()
+}
+
+func elevationpath(ll []LatLng, s int) string {
+	p := url.Values{}
+	p.Set("path", encodeLatLngs(ll))
+	p.Set("samples", fmt.Sprintf("%d", s))
+	return "elevation/json?" + p.Encode()
+}
+
+func elevationpathpoly(poly string, s int) string {
+	p := url.Values{}
+	p.Set("path", "enc:"+poly)
+	p.Set("samples", fmt.Sprintf("%d", s))
+	return "elevation/json?" + p.Encode()
+}
+
+type ElevationResponse struct {
+	Results []struct {
+		Elevation  float64 `json:"elevation"`
+		Location   LatLng  `json:"location"`
+		Resolution float64 `json:"resolution"`
+	}
+	Status string `json:"status"`
+}

maps.go

@@ -86,6 +86,14 @@ func encodeLocations(ls []Location) string {
 	return strings.Join(s, "|")
 }
 
+func encodeLatLngs(ll []LatLng) string {
+	s := make([]string, len(ll))
+	for i, l := range ll {
+		s[i] = l.Location()
+	}
+	return strings.Join(s, "|")
+}
+
 func Float64(f float64) *float64 {
 	return &f
 }

maps_test.go

@@ -102,3 +102,39 @@ func TestTimeZone(t *testing.T) {
 	}
 	t.Logf("%v", r)
 }
+
+func TestElevation(t *testing.T) {
+	c := NewClient("")
+	ll := []LatLng{{39.7391536, -104.9847034}}
+	t.Logf("%s", baseURL+elevation(ll))
+	r, err := c.Elevation(ll)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	t.Logf("%v", r)
+
+	p := "gfo}EtohhU"
+	t.Logf("%s", baseURL+elevationpoly(p))
+	r, err = c.ElevationPolyline(p)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	t.Logf("%v", r)
+
+	samples := 3
+	ll = []LatLng{{36.578581, -118.291994}, {36.23998, -116.83171}}
+	t.Logf("%s", baseURL+elevationpath(ll, samples))
+	r, err = c.ElevationPath(ll, samples)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	t.Logf("%v", r)
+
+	p = "gfo}EtohhUxD@bAxJmGF"
+	t.Logf("%s", baseURL+elevationpathpoly(p, samples))
+	r, err = c.ElevationPathPoly(p, samples)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	t.Logf("%v", r)
+}