refactor(geobase): unit types to singluar form #264

dart/geobase/lib/src/common/conversions/angle_unit.dart

@@ -15,46 +15,48 @@ import 'dart:math';
 /// ```dart
 /// /// Convert directly from and to radians.
 /// final radians = 3.14159; // ~pi
-/// final degreesUnit = AngleUnit.degrees;
-/// final degrees = degreesUnit.fromRadians(radians); // ~180.0
-/// final radians2 = degreesUnit.toRadians(degrees); // ~3.14159
+/// final degrees = AngleUnit.degree.fromRadians(radians); // ~180.0
+/// final radians2 = AngleUnit.degree.toRadians(degrees); // ~3.14159
 ///
 /// /// You can also convert between units without using radians.
-/// final gradians = degreesUnit.toUnits(degrees, AngleUnit.gradians); // ~200.0
+/// final gradians = 
+///     AngleUnit.degree.toUnit(degrees, AngleUnit.gradian); // ~200.0
 /// ```
+/// 
+/// See also [Angle](https://en.wikipedia.org/wiki/Angle) in Wikipedia.
 enum AngleUnit {
   /// 1 milliradian is equal to 0.001 radians.
-  milliradians(0.001, 'mrad'),
+  milliradian(0.001, 'mrad'),
 
   /// The SI base unit for angles.
   ///
   /// 1 radian is approximately 57.296 degrees.
-  radians(1.0, 'rad'),
+  radian(1.0, 'rad'),
 
   /// 1 arc second is equal to π / (180 * 60 * 60) radians.
   ///
   /// 1 degree contains 60 * 60 = 3600 arc seconds.
-  arcSeconds(pi / (180 * 60 * 60), 'arcsec'),
+  arcSecond(pi / (180 * 60 * 60), 'arcsec'),
 
   /// 1 arc minute is equal to π / (180 * 60) radians.
   ///
   /// 1 degree contains 60 arc minutes.
-  arcMinutes(pi / (180 * 60), 'arcmin'),
+  arcMinute(pi / (180 * 60), 'arcmin'),
 
   /// 1 degree is equal to π / 180 radians.
   ///
   /// 1 degree is 1/360 of a full circle.
-  degrees(pi / 180, 'deg'),
+  degree(pi / 180, 'deg'),
 
   /// 1 gradian is equal to π / 200 radians.
   ///
   /// 1 gradian is 1/400 of a full circle.
-  gradians(pi / 200, 'gon'),
+  gradian(pi / 200, 'gon'),
 
   /// 1 turn is equal to 2π radians.
   ///
   /// 1 turn is a full circle.
-  turns(2 * pi, 'turn');
+  turn(2 * pi, 'turn');
 
   /// The conversion factor to radians.
   final double factorToRadians;
@@ -75,13 +77,13 @@ enum AngleUnit {
   }
 
   /// Convert a value from this unit to another unit.
-  double toUnits(double value, AngleUnit targetUnit) {
+  double toUnit(double value, AngleUnit targetUnit) {
     final valueInRadians = toRadians(value);
     return targetUnit.fromRadians(valueInRadians);
   }
 
   /// Convert a value from another unit to this unit.
-  double fromUnits(double value, AngleUnit sourceUnit) {
+  double fromUnit(double value, AngleUnit sourceUnit) {
     final valueInRadians = sourceUnit.toRadians(value);
     return fromRadians(valueInRadians);
   }

dart/geobase/lib/src/common/conversions/area_unit.dart

@@ -13,43 +13,45 @@
 /// ```dart
 /// /// Convert directly from and to square meters.
 /// final squareMeters = 10000.0;
-/// final sqKmUnit = AreaUnit.squareKilometers;
+/// final sqKmUnit = AreaUnit.squareKilometer;
 /// final squareKilometers = sqKmUnit.fromSquareMeters(squareMeters); // 0.01
 /// final squareMeters2 = sqKmUnit.toSquareMeters(squareKilometers); // 10000.0
 ///
 /// /// You can also convert between units without using square meters.
-/// final acres = sqKmUnit.toUnits(squareKilometers, AreaUnit.acres); // ~2.4711
+/// final acres = sqKmUnit.toUnit(squareKilometers, AreaUnit.acre); // ~2.4711
 /// ```
+/// 
+/// See also [Area](https://en.wikipedia.org/wiki/Area) in Wikipedia.
 enum AreaUnit {
   /// 1 square millimeter is equal to 1e-6 square meters.
-  squareMillimeters(1e-6, 'mm²'),
+  squareMillimeter(1e-6, 'mm²'),
 
   /// 1 square centimeter is equal to 1e-4 square meters.
-  squareCentimeters(1e-4, 'cm²'),
+  squareCentimeter(1e-4, 'cm²'),
 
   /// The SI base unit for area.
-  squareMeters(1.0, 'm²'),
+  squareMeter(1.0, 'm²'),
 
   /// 1 square kilometer is equal to 1e+6 square meters.
-  squareKilometers(1e6, 'km²'),
+  squareKilometer(1e6, 'km²'),
 
   /// 1 square inch is equal to 0.00064516 square meters.
-  squareInches(0.00064516, 'in²'),
+  squareInch(0.00064516, 'in²'),
 
   /// 1 square foot is equal to 0.09290304 square meters.
-  squareFeet(0.09290304, 'ft²'),
+  squareFoot(0.09290304, 'ft²'),
 
   /// 1 square yard is equal to 0.83612736 square meters.
-  squareYards(0.83612736, 'yd²'),
+  squareYard(0.83612736, 'yd²'),
 
   /// 1 square mile is equal to 2589988.11 square meters.
-  squareMiles(2589988.11, 'mi²'),
+  squareMile(2589988.11, 'mi²'),
 
   /// 1 acre is equal to 4046.8564224 square meters.
-  acres(4046.8564224, 'ac'),
+  acre(4046.8564224, 'ac'),
 
   /// 1 hectare is equal to 10000 square meters.
-  hectares(10000.0, 'ha');
+  hectare(10000.0, 'ha');
 
   /// The conversion factor to square meters.
   final double factorToSquareMeters;
@@ -70,13 +72,13 @@ enum AreaUnit {
   }
 
   /// Convert a value from this unit to another unit.
-  double toUnits(double value, AreaUnit targetUnit) {
+  double toUnit(double value, AreaUnit targetUnit) {
     final valueInSquareMeters = toSquareMeters(value);
     return targetUnit.fromSquareMeters(valueInSquareMeters);
   }
 
   /// Convert a value from another unit to this unit.
-  double fromUnits(double value, AreaUnit sourceUnit) {
+  double fromUnit(double value, AreaUnit sourceUnit) {
     final valueInSquareMeters = sourceUnit.toSquareMeters(value);
     return fromSquareMeters(valueInSquareMeters);
   }

dart/geobase/lib/src/common/conversions/distance_unit.dart

@@ -13,43 +13,47 @@
 /// ```dart
 /// /// Convert directly from and to meters.
 /// final meters = 4000.0;
-/// final kmUnit = DistanceUnit.kilometers;
+/// final kmUnit = DistanceUnit.kilometer;
 /// final kilometers = kmUnit.fromMeters(meters); // 4.0
 /// final meters2 = kmUnit.toMeters(kilometers); // 4000.0
 ///
 /// /// You can also convert between units wihout using meters.
-/// final miles = kmUnit.toUnits(kilometers, DistanceUnit.miles); // ~ 2.485484
+/// final miles = kmUnit.toUnit(kilometers, DistanceUnit.mile); // ~ 2.485484
 /// ```dart
+///
+/// See also [Unit of length](https://en.wikipedia.org/wiki/Unit_of_length) and
+/// [Orders of magnitude (length)](https://en.wikipedia.org/wiki/Orders_of_magnitude_(length))
+/// in Wikipedia.
 enum DistanceUnit {
   /// 1 millimeter is equal to 0.001 meters.
-  millimeters(0.001, 'mm'),
+  millimeter(0.001, 'mm'),
 
   /// 1 centimeter is equal to 0.01 meters.
-  centimeters(0.01, 'cm'),
+  centimeter(0.01, 'cm'),
 
-  /// The SI base unit for distance .
-  meters(1.0, 'm'),
+  /// The SI base unit for distance.
+  meter(1.0, 'm'),
 
   /// 1 kilometer is equal to 1000 meters.
-  kilometers(1000.0, 'km'),
+  kilometer(1000.0, 'km'),
 
   /// 1 inch is equal to 0.0254 meters.
-  inches(0.0254, 'in'),
+  inch(0.0254, 'in'),
 
   /// 1 foot is equal to 0.3048 meters.
-  feet(0.3048, 'ft'),
+  foot(0.3048, 'ft'),
 
   /// 1 yard is equal to 0.9144 meters.
-  yards(0.9144, 'yd'),
+  yard(0.9144, 'yd'),
 
   /// 1 mile is equal to 1609.344 meters.
-  miles(1609.344, 'mi'),
+  mile(1609.344, 'mi'),
 
   /// 1 nautical mile is equal to 1852 meters.
   ///
   /// Official unit symbols for nautical miles are "NM", "nmi" or "M" depending
   /// on the context ([Wikipedia](https://en.wikipedia.org/wiki/Nautical_mile)).
-  nauticalMiles(1852.0, 'nmi');
+  nauticalMile(1852.0, 'nmi');
 
   /// The conversion factor to meters.
   final double factorToMeters;
@@ -70,13 +74,13 @@ enum DistanceUnit {
   }
 
   /// Convert a value from this unit to another unit.
-  double toUnits(double value, DistanceUnit targetUnit) {
+  double toUnit(double value, DistanceUnit targetUnit) {
     final valueInMeters = toMeters(value);
     return targetUnit.fromMeters(valueInMeters);
   }
 
   /// Convert a value from another unit to this unit.
-  double fromUnits(double value, DistanceUnit sourceUnit) {
+  double fromUnit(double value, DistanceUnit sourceUnit) {
     final valueInMeters = sourceUnit.toMeters(value);
     return fromMeters(valueInMeters);
   }