56 lines
1.9 KiB
Dart
56 lines
1.9 KiB
Dart
import 'package:nmea/nmea.dart';
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class Gngga extends TalkerSentence {
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static const String id = "GxGGA";
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Gngga({required super.raw});
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@override
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bool get valid => super.valid && fields.length >= 15;
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String get utcOfPositionFix => _field(1);
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int get gpsQualityIndicator => _parseInt(_field(6), fallback: 0);
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String get latitudeDirection => _field(3).toUpperCase();
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double get latitude => _parseLatitude(_field(2), latitudeDirection) ?? 0.0;
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String get longitudeDirection => _field(5).toUpperCase();
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double get longitude => _parseLongitude(_field(4), longitudeDirection) ?? 0.0;
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int get numberOfSvsInUse => _parseInt(_field(7), fallback: 0);
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double get hdop => _parseDouble(_field(8), fallback: 0.0);
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double get altitudeAboveMeanSeaLevel =>
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_parseDouble(_field(9), fallback: 0.0);
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double get geoidSeparation => _parseDouble(_field(11), fallback: 0.0);
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String _field(int index) {
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if (index < 0 || index >= fields.length) return '';
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return fields[index].trim();
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}
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int _parseInt(String value, {required int fallback}) {
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return int.tryParse(value) ?? fallback;
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}
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double _parseDouble(String value, {required double fallback}) {
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return double.tryParse(value) ?? fallback;
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}
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double? _parseLatitude(String value, String direction) {
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if (value.length < 4) return null; // ddmm.mmmm
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final deg = double.tryParse(value.substring(0, 2));
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final min = double.tryParse(value.substring(2));
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if (deg == null || min == null) return null;
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final result = deg + (min / 60.0);
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return direction == 'S' ? -result : result;
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}
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double? _parseLongitude(String value, String direction) {
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if (value.length < 5) return null; // dddmm.mmmm
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final deg = double.tryParse(value.substring(0, 3));
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final min = double.tryParse(value.substring(3));
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if (deg == null || min == null) return null;
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final result = deg + (min / 60.0);
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return direction == 'W' ? -result : result;
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}
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}
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