Add upport for elevation checking

elevation.go

@@ -1,18 +1,123 @@
 package geonames
 
-type ElevationSRTM1 struct {
+import (
+	"context"
+	"fmt"
+)
+
+type srtm1Resp struct {
 	Srtm1 int     `json:"srtm1"`
 	Lng   float64 `json:"lng"`
 	Lat   float64 `json:"lat"`
 }
 
+type srtm3Resp struct {
+	Srtm3 int     `json:"srtm3"`
+	Lng   float64 `json:"lng"`
+	Lat   float64 `json:"lat"`
+}
+
+type asterResp struct {
+	Astergdem int     `json:"astergdem"`
+	Lng       float64 `json:"lng"`
+	Lat       float64 `json:"lat"`
+}
+
+type gtopoResp struct {
+	Gtopo30 int     `json:"gtopo30"`
+	Lng     float64 `json:"lng"`
+	Lat     float64 `json:"lat"`
+}
+
+// Elevation holds elevation data expressed in meters npm.
 type Elevation struct {
-	Type string
-	Lat  float64
-	Lng  float64
+	Type  string
+	Lat   float64
+	Lng   float64
+	Value int
+}
+
+// GetElevationSRTM1 takes two float numbers representing latitude and longitude
+// and returns elevation in meters according to SRMT1. The sample area is ca 30m x 30m.
+// Ocean areas returns "no data", and have assigned a value of -32768.
+func (c *Client) GetElevationSRTM1(ctx context.Context, lat, lng float64) (Elevation, error) {
+	path := fmt.Sprintf("/srtm1JSON?lat=%.3f&lng=%.3f&username=%s", lat, lng, c.UserName)
+	var er srtm1Resp
+	err := c.get(ctx, c.BaseURL+path, &er)
+	if err != nil {
+		return Elevation{}, err
+	}
+	e := Elevation{
+		Type:  "srtm1",
+		Lat:   er.Lat,
+		Lng:   er.Lng,
+		Value: er.Srtm1,
+	}
+	return e, nil
 }
 
-func GetElevationSRTM1() Elevation {
+// GetElevationSRTM3 takes two float numbers representing latitude and longitude
+// and returns elevation in meters according to SRMT3.
+//
+// SRTM data consisted of a specially modified radar system that flew
+// onboard the Space Shuttle Endeavour during an 11-day mission in February of 2000.
+// The dataset covers land areas between 60 degrees north and 56 degrees south.
+// SRTM3 data are data points located every 3-arc-second (approximately 90 meters) on a latitude/longitude grid.
+func (c *Client) GetElevationSRTM3(ctx context.Context, lat, lng float64) (Elevation, error) {
+	path := fmt.Sprintf("/srtm3JSON?lat=%.3f&lng=%.3f&username=%s", lat, lng, c.UserName)
+	var er srtm3Resp
+	err := c.get(ctx, c.BaseURL+path, &er)
+	if err != nil {
+		return Elevation{}, err
+	}
+	e := Elevation{
+		Type:  "srtm3",
+		Lat:   er.Lat,
+		Lng:   er.Lng,
+		Value: er.Srtm3,
+	}
+	return e, nil
+}
+
+// GetElevationAstergdem returns elevation in meters according to aster gdem.
+//
+// Sample are: ca 30m x 30m, between 83N and 65S latitude. Ocean areas have been assigned a value of -32768
+func (c *Client) GetElevationAstergdem(ctx context.Context, lat, lng float64) (Elevation, error) {
+	path := fmt.Sprintf("/astergdemJSON?lat=%.3f&lng=%.3f&username=%s", lat, lng, c.UserName)
+	var er asterResp
+	err := c.get(ctx, c.BaseURL+path, &er)
+	if err != nil {
+		return Elevation{}, err
+	}
+	e := Elevation{
+		Type:  "astergdem",
+		Lat:   er.Lat,
+		Lng:   er.Lng,
+		Value: er.Astergdem,
+	}
+	return e, nil
+}
 
-	return Elevation{}
+// GetElevationGTOPO30 returns elevation data sampled for the area of 1km x 1km.
+//
+// Ocean areas have assigned value of -9999 indicating no data for the requested lat and lng.
+// GTOPO30 is a global digital elevation model (DEM) with a horizontal grid spacing
+// of 30 arc seconds (approximately 1 kilometer).
+// GTOPO30 is derived from several raster and vector sources of topographic information.
+//
+// Documentation: http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/gtopo30_info
+func (c *Client) GetElevationGTOPO30(ctx context.Context, lat, lng float64) (Elevation, error) {
+	path := fmt.Sprintf("/gtopo30JSON?lat=%.3f&lng=%.3f&username=%s", lat, lng, c.UserName)
+	var er gtopoResp
+	err := c.get(ctx, c.BaseURL+path, &er)
+	if err != nil {
+		return Elevation{}, err
+	}
+	e := Elevation{
+		Type:  "gtopo30",
+		Lat:   er.Lat,
+		Lng:   er.Lng,
+		Value: er.Gtopo30,
+	}
+	return e, nil
 }

elevation_test.go

@@ -2,48 +2,157 @@ package geonames_test
 
 import (
 	"bytes"
+	"context"
+	"fmt"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/qba73/geonames"
 )
 
-// ts is a helper func that creates a test server with embedded URI validation.
-var testServer = func(reader io.Reader, wantURI string, t *testing.T) *httptest.Server {
+// newElevationtestServer creates a test server with embedded URI validation.
+func newElevationTestServer(data []byte, wantURI string, t *testing.T) *httptest.Server {
 	ts := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 		gotReqURI := r.RequestURI
 		verifyURIs(wantURI, gotReqURI, t)
-		_, err := io.Copy(rw, reader)
+		_, err := io.Copy(rw, bytes.NewBuffer(data))
 		if err != nil {
 			t.Fatal(err)
 		}
 	}))
 	return ts
 }
 
-func TestGetElevationReturnsDataOnValidInput(t *testing.T) {
+func TestGetElevationSRTM1ReturnsDataOnValidInput(t *testing.T) {
 	t.Parallel()
 
-	resp := new(bytes.Buffer)
-	resp.Read([]byte(`23`))
+	lat, lng := 50.0, 50.0
+	wantReqURI := fmt.Sprintf("/srtm1JSON?lat=%.3f&lng=%.3f&username=DummyUser", lat, lng)
 
-	ts := testServer(&resp)
+	ts := newElevationTestServer(srtm1, wantReqURI, t)
+	defer ts.Close()
+
+	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := geonames.Elevation{
+		Type:  "srtm1",
+		Lat:   54.166,
+		Lng:   -6.083,
+		Value: 375,
+	}
 
+	got, err := client.GetElevationSRTM1(context.Background(), lat, lng)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !cmp.Equal(want, got) {
+		t.Error(cmp.Diff(want, got))
+	}
 }
 
-func TestGetElevationValidInput(t *testing.T) {
+func TestGetElevationSRTM3ReturnsDataOnValidInput(t *testing.T) {
 	t.Parallel()
 
-	wantReqURI := "/srtm1JSON?lat=50&lng=50&username=DummyUser"
-	ts := newTestServer(testFile, wantReqURI, t)
+	lat, lng := 55.166, -6.088
+	wantReqURI := fmt.Sprintf("/srtm3JSON?lat=%.3f&lng=%.3f&username=DummyUser", lat, lng)
+
+	ts := newElevationTestServer(srtm3, wantReqURI, t)
 	defer ts.Close()
 
 	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	client.GetElevation()
+	want := geonames.Elevation{
+		Type:  "srtm3",
+		Lat:   55.166,
+		Lng:   -6.088,
+		Value: 263,
+	}
+
+	got, err := client.GetElevationSRTM3(context.Background(), lat, lng)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !cmp.Equal(want, got) {
+		t.Error(cmp.Diff(want, got))
+	}
 }
+
+func TestGetElevationAstergdemReturnsDataOnValidInput(t *testing.T) {
+	t.Parallel()
+
+	lat, lng := 50.01, 10.20
+	wantReqURI := fmt.Sprintf("/astergdemJSON?lat=%.3f&lng=%.3f&username=DummyUser", lat, lng)
+
+	ts := newElevationTestServer(astergdem, wantReqURI, t)
+	defer ts.Close()
+
+	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := geonames.Elevation{
+		Type:  "astergdem",
+		Lat:   50.010,
+		Lng:   10.200,
+		Value: 206,
+	}
+
+	got, err := client.GetElevationAstergdem(context.Background(), lat, lng)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !cmp.Equal(want, got) {
+		t.Error(cmp.Diff(want, got))
+	}
+}
+
+func TestGetElevationGTOPO30ReturnsDataOnValidInput(t *testing.T) {
+	t.Parallel()
+
+	lat, lng := 47.01, 10.2
+	wantReqURI := fmt.Sprintf("/gtopo30JSON?lat=%.3f&lng=%.3f&username=DummyUser", lat, lng)
+
+	ts := newElevationTestServer(gtopo30, wantReqURI, t)
+	defer ts.Close()
+
+	client, err := geonames.NewClient("DummyUser", geonames.WithBaseURL(ts.URL))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := geonames.Elevation{
+		Type:  "gtopo30",
+		Lat:   47.01,
+		Lng:   10.20,
+		Value: 2632,
+	}
+
+	got, err := client.GetElevationGTOPO30(context.Background(), lat, lng)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !cmp.Equal(want, got) {
+		t.Error(cmp.Diff(want, got))
+	}
+}
+
+var (
+	srtm1     = []byte(`{"srtm1":375,"lng":-6.083,"lat":54.166}`)
+	srtm3     = []byte(`{"srtm3":263,"lng":-6.088,"lat":55.166}`)
+	astergdem = []byte(`{"lng":10.2,"astergdem":206,"lat":50.01}`)
+	gtopo30   = []byte(`{"lng":10.2,"gtopo30":2632,"lat":47.01}`)
+)