Merge pull request #3 from im7mortal/catchup_with_python

Catchup with python

README.md

@@ -5,7 +5,8 @@
 UTM
 ===
 
-Bidirectional UTM-WGS84 converter for golang. It use logic from [UTM python version](https://pypi.python.org/pypi/utm) by Tobias Bieniek
+Bidirectional UTM-WGS84 converter for golang. It use logic from [UTM python version](https://pypi.python.org/pypi/utm)
+by Tobias Bieniek
 
 Usage
 -----
@@ -15,13 +16,13 @@ Usage
 Convert a latitude, longitude into an UTM coordinate
 
 ```go
-	easting, northing, zoneNumber, zoneLetter, err := UTM.FromLatLon(40.71435, -74.00597, false)
+    easting, northing, zoneNumber, zoneLetter, err := UTM.FromLatLon(40.71435, -74.00597, false)
 ```
 
 Convert an UTM coordinate into a latitude, longitude.
 
 ```go
-	latitude, longitude, err := UTM.ToLatLon(377486, 6296562, 30, "V")
+    latitude, longitude, err := UTM.ToLatLon(377486, 6296562, 30, "V")
 ```
 
 Since the zone letter is not strictly needed for the conversion you may also
@@ -30,24 +31,26 @@ to either ``true`` or ``false``. In this case you should define fields clearly(!
 You can't set ZoneLetter or northern both.
 
 ```go
-	latitude, longitude, err := UTM.ToLatLon(377486, 6296562, 30, "", false)
+    latitude, longitude, err := UTM.ToLatLon(377486, 6296562, 30, "", false)
 ```
 
-The UTM coordinate system is explained on this [Wikipedia page](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system)
+The UTM coordinate system is explained on
+this [Wikipedia page](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system)
 
 Speed
 -----
 
-Benchmark             | Amount of iterations | Average speed
---------------------- | -------------------- | -------------
-ToLatLon              | 10000000             | 123 ns/op
-ToLatLonWithNorthern  | 10000000             | 121 ns/op
-FromLatLon            | 20000000             | 80.6 ns/op
+ Benchmark            | Amount of iterations | Average speed 
+----------------------|----------------------|---------------
+ ToLatLon             | 10000000             | 123 ns/op     
+ ToLatLonWithNorthern | 10000000             | 121 ns/op     
+ FromLatLon           | 20000000             | 80.6 ns/op    
 
 > go test -bench=.
 
 Full example
 -----------
+
 ```go
 package main
 

example/example.go

@@ -1,8 +1,8 @@
 package main
 
 import (
-	"github.com/im7mortal/UTM"
 	"fmt"
+	"github.com/im7mortal/UTM"
 )
 
 func main() {
@@ -13,7 +13,7 @@ func main() {
 	}
 	fmt.Println(
 		fmt.Sprintf(
-			"Easting: %d; Northing: %d; ZoneNumber: %d; ZoneLetter: %s;",
+			"Easting: %f; Northing: %f; ZoneNumber: %d; ZoneLetter: %s;",
 			easting,
 			northing,
 			zoneNumber,
@@ -26,7 +26,7 @@ func main() {
 	}
 	fmt.Println(
 		fmt.Sprintf(
-			"Easting: %d; Northing: %d; ZoneNumber: %d; ZoneLetter: %s;",
+			"Easting: %f; Northing: %f; ZoneNumber: %d; ZoneLetter: %s;",
 			easting,
 			northing,
 			zoneNumber,

utm.go

@@ -46,7 +46,7 @@ func rad(d float64) float64 { return d * x }
 func deg(r float64) float64 { return r / x }
 
 var zoneLetters = []zoneLetter{
-	{84, " "},
+	{84, "X"},
 	{72, "X"},
 	{64, "W"},
 	{56, "V"},
@@ -71,7 +71,7 @@ var zoneLetters = []zoneLetter{
 
 // ToLatLon convert Universal Transverse Mercator coordinates to a latitude and longitude
 // Since the zone letter is not strictly needed for the conversion you may also
-// the ``northern`` parameter instead, which is a named parameter and can be set
+// the “northern“ parameter instead, which is a named parameter and can be set
 // to either true or false. In this case you should define fields clearly
 // You can't set ZoneLetter or northern both.
 func ToLatLon(easting, northing float64, zoneNumber int, zoneLetter string, northern ...bool) (latitude, longitude float64, err error) {
@@ -143,7 +143,7 @@ func ToLatLon(easting, northing float64, zoneNumber int, zoneLetter string, nort
 	n := r / epSinSqrt
 	rad := (1 - e) / epSin
 
-	c := fe * pCos * pCos
+	c := eP2 * pCos * pCos
 	c2 := c * c
 
 	d := x / (n * k0)
@@ -153,8 +153,8 @@ func ToLatLon(easting, northing float64, zoneNumber int, zoneLetter string, nort
 	d5 := d4 * d
 	d6 := d5 * d
 
-	latitude = pRad - (pTan / rad) *
-		(d2/2 -
+	latitude = pRad - (pTan/rad)*
+		(d2/2-
 			d4/24*(5+3*pTan2+10*c-4*c2-9*eP2)) +
 		d6/720*(61+90*pTan2+298*c+45*pTan4-252*eP2-3*c2)
 
@@ -226,11 +226,11 @@ func FromLatLon(latitude, longitude float64, northern bool) (easting, northing f
 		m2*math.Sin(2*latRad) +
 		m3*math.Sin(4*latRad) -
 		m4*math.Sin(6*latRad))
-	easting = k0*n * (a +
-		a3/6*(1-latTan2+c) +
+	easting = k0*n*(a+
+		a3/6*(1-latTan2+c)+
 		a5/120*(5-18*latTan2+latTan4+72*c-58*eP2)) + 500000
-	northing = k0 * (m + n*latTan * (a2/2 +
-		a4/24*(5-latTan2+9*c+4*c*c) +
+	northing = k0 * (m + n*latTan*(a2/2+
+		a4/24*(5-latTan2+9*c+4*c*c)+
 		a6/720*(61-58*latTan2+latTan4+600*c-330*eP2)))
 
 	if latitude < 0 {
@@ -255,13 +255,13 @@ func latLonToZoneNumber(latitude float64, longitude float64) int {
 	}
 
 	if 72 <= latitude && latitude <= 84 && longitude >= 0 {
-		if longitude <= 9 {
+		if longitude < 9 {
 			return 31
-		} else if longitude <= 21 {
+		} else if longitude < 21 {
 			return 33
-		} else if longitude <= 33 {
+		} else if longitude < 33 {
 			return 35
-		} else if longitude <= 42 {
+		} else if longitude < 42 {
 			return 37
 		}
 	}

utm_deprecated.go

@@ -14,7 +14,7 @@ func FromLatLonF(lat, lon float64) (easting, northing float64) {
 	return
 }
 
-//Coordinate contains coordinates in the Universal Transverse Mercator coordinate system
+// Coordinate contains coordinates in the Universal Transverse Mercator coordinate system
 //
 // Deprecated: Use ToLatLon functions to convert LatLon instead.
 type Coordinate struct {
@@ -33,7 +33,7 @@ func (point *LatLon) FromLatLon() (coord Coordinate, err error) {
 	return
 }
 
-//LatLon contains a latitude and longitude
+// LatLon contains a latitude and longitude
 //
 // Deprecated: Use FromLatLon functions to convert LatLon instead.
 type LatLon struct {
@@ -43,7 +43,7 @@ type LatLon struct {
 
 // ToLatLon convert Universal Transverse Mercator coordinates to a latitude and longitude
 // Since the zone letter is not strictly needed for the conversion you may also
-// the ``northern`` parameter instead, which is a named parameter and can be set
+// the “northern“ parameter instead, which is a named parameter and can be set
 // to either true or false. In this case you should define fields clearly
 // You can't set ZoneLetter or northern both.
 //

utm_deprecated_test.go

@@ -1,8 +1,8 @@
 package UTM_test
 
 import (
-	"testing"
 	"github.com/im7mortal/UTM"
+	"testing"
 )
 
 type testDataDeprecated struct {

utm_test.go

@@ -72,6 +72,12 @@ var knownValues = []testData{
 		testCoordinate{377486, 6296562, 30, "V"},
 		true,
 	},
+	// Latitude 84
+	{
+		testLatLon{84, -5.00601},
+		testCoordinate{476594, 9328501, 30, "X"},
+		true,
+	},
 }
 
 func TestToLatLon(t *testing.T) {
@@ -149,15 +155,15 @@ func TestFromLatLonBadInput(t *testing.T) {
 		latLon.Latitude = i / 100
 		_, _, _, _, err := UTM.FromLatLon(latLon.Latitude, latLon.Longitude, false)
 		if err != nil {
-			t.Errorf("not cover Latitude %d", i/100)
+			t.Errorf("not cover Latitude %f", i/100)
 		}
 	}
 	latLon.Latitude = 0
 	for i := -18000.0; i < 18001.0; i++ {
 		latLon.Longitude = i / 100
 		_, _, _, _, err := UTM.FromLatLon(latLon.Latitude, latLon.Longitude, false)
 		if err != nil {
-			t.Errorf("not cover Longitude %d", i/100)
+			t.Errorf("not cover Longitude %f", i/100)
 		}
 	}
 }