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+# Upgrading
+
+## From 1.x to 2.x
+
+Magellan 2.x introduce some breaking changes, which enforces some migrations.  
+The following 5 Steps provide all the necessary information by examples.
+
+### Step 1: Migrate Model
+
+With Magellan 2.x we move from having a trait with casting logic to the [default Laravel Way of using casters](https://laravel.com/docs/master/eloquent-mutators#attribute-casting) and made all
+`Geometry` classes available as casters for a better syntax.
+
+#### In Magellan 1.x
+
+```php
+use Clickbar\Magellan\Database\Eloquent\HasPostgisColumns;
+use Clickbar\Magellan\Cast\BBoxCast;
+
+class Port extends Model
+{
+    use HasPostgisColumns;
+
+    protected array $postgisColumns = [
+        'location' => [
+            'type' => 'geometry',
+            'srid' => 4326,
+        ],
+    ];
+    
+    protected array $casts = [
+        'bounding_box' => BBoxCast::class
+    ];
+}
+```
+
+#### In Magellan 2.x
+
+```php
+use Clickbar\Magellan\Data\Geometries\Point;
+use Clickbar\Magellan\Data\Boxes\Box2D;
+
+class Port extends Model
+{
+    protected array $casts = [
+        'location' => Point::class,
+        'bounding_box' => Box2D::class,
+    ];
+}
+```
+
+Remove the `HasPostgisColumns` trait and the
+`$postgisColumns` array and add the appropriate cast based on the geometry in the database (e.g. Point::class, Geometry::class, LineString::class, ...).
+Also change from the generic `BBoxCast` to the appropriate Box model class (e.g. `Box2D::class` or `Box3D::class`).
+
+### Step 2: Migrate stSelect, stWhere, ...
+
+With the 2.x release we've removed the custom
+`st`-prefixed query builder methods. You can now use the default Laravel methods.
+The `ST` functions can now be used directly in the query builder methods.
+For renaming the results we added a new
+`Aliased` expression class, which can be used to rename the result of a function.
+But we also added a utility function on all `ST` expressions: `ST::distanceSphere(...)->as("myalias")`.
+
+#### In Magellan 1.x:
+
+```php
+$currentShipPosition = Point::makeGeodetic(50.107471773560114, 8.679861151457937);
+$portsWithDistance = Port::select(['name', 'country'])
+    ->stSelect(ST::distanceSphere($currentShipPosition, 'location'), as: 'distance_to_ship')
+    ->stWhere(ST::distanceSphere($currentShipPosition, 'location'), '<=', 50000)
+    ->stOrderBy(ST::distanceSphere($currentShipPosition, 'location'))
+    ->get();
+```
+
+##### In Magellan 2.x:
+
+```php
+$currentShipPosition = Point::makeGeodetic(50.107471773560114, 8.679861151457937);
+$portsWithDistance = Port::select(['name', 'country'])
+    ->addSelect(ST::distanceSphere($currentShipPosition, 'location')->as('distance_to_ship'))
+    ->where(ST::distanceSphere($currentShipPosition, 'location'), '<=', 50000)
+    ->orderBy(ST::distanceSphere($currentShipPosition, 'location'))
+    ->withMagellanCasts() // <-- automatically adds casts for st functions returning geometry or bbox
+    ->get();    
+```
+
+For almost all methods, we can simply remove the `st-` prefix and use the default Laravel methods.
+
+`stSelect` is a special case: It acted like an
+`addSelect` and also automatically took care of the casting. Therefore, it must be replaced by a call to
+`addSelect` and we also need to add a call to `withMagellanCasts()`.
+
+In fact, in this concrete example, we can now completely get rid of the `addSelect` by merging it into the other
+`select`:
+
+```php
+$portsWithDistance = Port::select([
+    'name', 
+    'country',
+    ST::distanceSphere($currentShipPosition, 'location')->as('distance_to_ship'),
+])
+```
+
+### Step 3: Migrate `GeometryType` Enum
+
+The 1.x version of Magellan always used a
+`::geometry` cast under the hood for all parameters that expected any kind of geometry. In case there was a function that could also take geography, the function had an optional parameter named
+`$geometryType` which could be used to tell Magellan to use `::geography` instead.
+With Magellan 2.x we decided to remove this. With the most amount of
+`ST_` functions of PostGIS being defined on geometry only anyway, we wanted to give back the developer a bit more control and also responsibility.
+
+If you want to cast your input, you now need to use the `AsGeometry` and
+`AsGeography` cast expressions wrapping the geometry or function you want to cast.
+
+But let's look at this using an example.
+If you want to use st_buffer to buffer a geometry using a radius in meters, you need a geography as input instead of geometry.
+
+#### In Magellan 1.x
+
+```php
+$bufferedPorts = Port::query()
+    ->stSelect(ST::buffer('location', 50, geometryType: GeometryType::geography), as: 'buffered_location'))
+    ->get();
+```
+
+#### In Magellan 2.x
+
+```php
+$bufferedPorts = Port::query()
+->select(ST::buffer(new AsGeography('location'), 50)->as('buffered_location'))
+->withCasts(['buffered_location' => Polygon::class]) // or ->withMagellanCasts()
+->get();
+```
+
+### Step 4: Migrate SRID transformation on insert/update
+
+> **_NOTE_** Only relevant if you used magellan.eloquent.transform_to_database_projection = true in config.
+
+#### In Magellan 1.x
+
+```php
+Port::create([
+    'name' => 'Magellan Home Port',
+    'country' => 'Germany',
+    'location' => Point::make(473054.9891044726, 5524365.310057224, srid: 25832),
+]);
+
+// -- or --
+
+$port = Port::find(1);
+$port->location = Point::make(473054.9891044726, 5524365.310057224, srid: 25832);
+$port->save();
+```
+
+#### In Magellan 2.x
+
+With the removal of the `HasPostgisColumns` trait we also removed the auto transform feature.  
+If you relied on this, you now need to transform it directly on insert or update using `ST::transform`:
+
+```php
+$point = Point::make(473054.9891044726, 5524365.310057224, srid: 25832);
+
+Port::create([
+    'name' => 'Magellan Home Port',
+    'country' => 'Germany',
+    'location' => ST::transform($point, 4326),
+]);
+
+// -- or --
+
+$port = Port::find(1);
+
+$port->query()->update([
+    'location' => ST::transform(Point::make(473054.9891044726, 5524365.310057224, srid: 25832), 4326),
+]);
+```
+
+### Step 5: Migrate GeometryWKBCast
+
+> **_NOTE_** Only relevant if you used the `GeometryWKBCast` directly somewhere
+
+#### In Magellan 1.x
+
+```php
+$hullWithArea = Port::select('country')
+    ->stSelect(ST::convexHull(ST::collect('location')), 'hull')
+    ->stSelect(ST::area(ST::convexHull(ST::collect('location'))))
+    ->groupBy('country')
+    ->withCasts(['hull' => GeometryWKBCast::class]) 
+    ->first();
+```
+
+#### In Magellan 2.x
+
+```php
+$hullWithArea = Port::query()
+    ->select([
+        'country',
+        ST::convexHull(ST::collect('location'))->as('hull'),
+        ST::area(ST::convexHull(ST::collect('location'))),
+    ])
+    ->groupBy('country')
+    ->withCasts(['hull' => Polygon::class]) 
+    ->first();
+```
+
+We removed the `GeometryWKBCast` class and added new casters using the appropriate Geometry class.
+
+### Step 6: Other Changes
+
+You can also go ahead and remove the `magellan.eloquent` config and the `magellan.model_directories` configs.
+
+We also renamed the `toString` function on Box classes to `toRawSql`.
+
+The `BBoxCast` class was refactored and the Box2D / Box3D classes should be used as casts directly instead.
+
+For a more detailed list of changes, please refer to the [CHANGELOG](CHANGELOG.md).
+