# Projections

Last updated:

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October 18, 2026

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\| 5 minutes read

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The Maps SDK for Flutter provides a `Projection` class that represents the base class for different geocoordinate systems.

## Supported projection types[​](#supported-projection-types "Direct link to Supported projection types")

* `WGS84` - World Geodetic System 1984
* `GK` - Gauss-Kruger
* `UTM` - Universal Transverse Mercator
* `LAM` - Lambert
* `BNG` - British National Grid
* `MGRS` - Military Grid Reference System
* `W3W` - What three words

You can check the projection type using the `type` getter:

```dart
final type = projection.type;

```

## WGS84 projection[​](#wgs84-projection "Direct link to WGS84 projection")

The **WGS84** projection is a widely used geodetic datum that serves as the foundation for GPS and other mapping systems.

Create a `WGS84` projection using a `Coordinates` object:

```dart
final obj = WGS84Projection(Coordinates(latitude: 5.0, longitude: 5.0));

```

Access and modify coordinates using the `coordinates` getter and setter:

```dart
final coordinates = obj.coordinates; // Get coordinates
obj.coordinates = Coordinates(latitude: 10.0, longitude: 10.0); // Set coordinates

```

info

The coordinates getter returns null if the coordinates are not set.

## GK projection[​](#gk-projection "Direct link to GK projection")

The **Gauss-Kruger** projection is a cylindrical map projection commonly used for large-scale mapping in regions with a north-south orientation. It divides the Earth into zones, each with its own coordinate system.

Create a `Gauss-Kruger` projection:

```dart
final obj = GKProjection(x: 6325113.72, y: 5082540.66, zone: 1);

```

Access values using the `easting`, `northing` and `zone` getters. Modify them using the `setFields` method:

```dart
final obj = GKProjection(x: 6325113.72, y: 5082540.66, zone: 1);

final type = obj.type; // ProjectionType.gk
final zone = obj.zone; // 1
final easting = obj.easting; // 6325113.72
final northing = obj.northing; // 5082540.66

obj.setFields(x: 1, y: 1, zone: 2);

final newZone = obj.zone; // 2
final newEasting = obj.easting; // 1
final newNorthing = obj.northing; // 1

```

danger

The `Gauss-Kruger` projection is currently supported only for countries that use **Bessel ellipsoid**. Converting to and from `Gauss-Kruger` projection for other countries will result in a `GemError.notSupported` error.

## BNG projection[​](#bng-projection "Direct link to BNG projection")

The **BNG** (British National Grid) projection is a coordinate system used in Great Britain for mapping and navigation. It provides a grid reference system for precise location identification.

Create a `BNG` projection:

```dart
final obj = BNGProjection(easting: 500000, northing: 4649776);

```

Access values using the `easting` and `northing` getters. Modify them using the `setFields` method:

```dart
final obj = BNGProjection(easting: 6325113.72, northing: 5082540.66);

obj.setFields(easting: 1, northing: 1);

final type = obj.type; // ProjectionType.bng
final newEasting = obj.easting; // 1
final newNorthing = obj.northing; // 1

```

## MGRS projection[​](#mgrs-projection "Direct link to MGRS projection")

The **MGRS** (Military Grid Reference System) projection is a coordinate system used by the military for precise location identification. It combines the UTM and UPS coordinate systems.

Create a `MGRS` projection:

```dart
final obj = MGRSProjection(easting: 99316, northing: 10163, zone: '30U', letters: 'XC');

```

Access values using the `easting`, `northing`, `zone` and `letters` getters. Modify them using the `setFields` method:

```dart
final obj = MGRSProjection(
    easting: 6325113, northing: 5082540, zone: 'A', letters: 'letters');

obj.setFields(
    easting: 1, northing: 1, zone: 'B', letters: 'newLetters');

final type = obj.type; // ProjectionType.mgrs
final newZone = obj.zone; // B
final newEasting = obj.easting; // 1
final newNorthing = obj.northing; // 1
final newLetters = obj.letters; // newLetters

```

## W3W projection[​](#w3w-projection "Direct link to W3W projection")

The **W3W** (What three words) projection is a geocoding system that divides the world into a grid of 3m x 3m squares, each identified by a unique combination of three words.

Create a `W3W` projection:

```dart
final obj = W3WProjection('token');

```

Access and modify the token and words values using the `token` and `words` getters and setters.

## LAM projection[​](#lam-projection "Direct link to LAM projection")

The **LAM** (Lambert) projection is a conic map projection commonly used for large-scale mapping in regions with an east-west orientation.

Create a `LAM` projection:

```dart
final obj = LAMProjection(x: 6325113.72, y: 5082540.66);

```

Access values using the `x` and `y` getters. Modify them using the `setFields` method.

```dart
final obj = LAMProjection(x: 6325113.72, y: 5082540.66);

obj.setFields(x: 1, y: 1);

final type = obj.type; // ProjectionType.lam
final newX = obj.x; // 1
final newY = obj.y; // 1

```

## UTM projection[​](#utm-projection "Direct link to UTM projection")

The **UTM** (Universal Transverse Mercator) projection is a global map projection that divides the world into a series of zones, each with its own coordinate system.

Create a `UTM` projection:

```dart
final obj = UTMProjection(x: 6325113.72, y: 5082540.66, zone: 1, hemisphere: Hemisphere.south);

```

Access values using the `x`, `y`, `zone` and `hemisphere` getters. Modify them using the `setFields` method:

```dart
final obj = UTMProjection(x: 6325113.72, y: 5082540.66, zone: 1, hemisphere: Hemisphere.south);

obj.setFields(x: 1, y: 1, zone: 2, hemisphere: Hemisphere.north);

final type = obj.type; // ProjectionType.utm
final newZone = obj.zone; // 2
final newX = obj.x; // 1
final newY = obj.y; // 1
final newHemisphere = obj.hemisphere; // Hemisphere.north

```

## Convert between projections[​](#convert-between-projections "Direct link to Convert between projections")

The `ProjectionService` class provides a method to convert between different projection types. Use the static `convert` method to transform coordinates from one projection to another:

```dart
final from = WGS84Projection(Coordinates(latitude: 51.5074, longitude: -0.1278));
final toType = ProjectionType.mgrs;

final completer = Completer<Projection?>();
ProjectionService.convert(
    from: from,
    toType: toType,
    onComplete: (error, result) {
        if (error == GemError.success) {
            completer.complete(result);
        } else {
            completer.completeError(error);
        }
    },
);

final result = await completer.future;
final mgrs = result as MGRSProjection;

final easting = mgrs.easting; // 99316
final northing = mgrs.northing; // 10163
final zone = mgrs.zone; // 30U
final letters = mgrs.letters; // XC

```

danger

`ProjectionService.convert` works with `W3WProjection` only if the `W3WProjection` object has a **valid** token that can be obtained from [what3words.com](https://developer.what3words.com/public-api). If the token is not set, the conversion will fail and the `GemError.notSupported` error will be returned via `onComplete`.

## Relevant examples demonstrating projections related features[​](#relevant-examples-demonstrating-projections-related-features "Direct link to Relevant examples demonstrating projections related features")

* [Projections](/docs/flutter/examples/maps-3dscene/projections.md)