Paumas implement dont clip flag (#593)

* implement dont_clip configuration option. closes #562.

README.md

@@ -178,6 +178,7 @@ name = "zoning"                              # used in the URL to reference this
 	                                         # It can also be used to group multiple ProviderLayers under the same namespace.
 	provider_layer = "test_postgis.rivers"   # must match a data provider layer
 	dont_simplify = true                     # optionally, turn off simplification for this layer. Default is false.
+	dont_clip = true                         # optionally, turn off clipping for this layer. Default is false.
 	min_zoom = 10                            # minimum zoom level to include this layer
 	max_zoom = 18                            # maximum zoom level to include this layer
 ```

atlas/layer.go

@@ -19,6 +19,9 @@ type Layer struct {
 	// DontSimplify indicates wheather feature simplification should be applied.
 	// We use a negative in the name so the default is to simplify
 	DontSimplify bool
+	// DontClip indicates wheather feature clipping should be applied.
+	// We use a negative in the name so the default is to clip
+	DontClip bool
 }
 
 // MVTName will return the value that will be encoded in the Name field when the layer is encoded as MVT

atlas/map.go

@@ -146,6 +146,7 @@ func (m Map) Encode(ctx context.Context, tile *slippy.Tile) ([]byte, error) {
 			mvtLayer := mvt.Layer{
 				Name:         l.MVTName(),
 				DontSimplify: l.DontSimplify,
+				DontClip: l.DontClip,
 			}
 
 			// on completion let the wait group know

cmd/internal/register/maps.go

@@ -162,6 +162,7 @@ func Maps(a *atlas.Atlas, maps []config.Map, providers map[string]provider.Tiler
 				DefaultTags:       defaultTags,
 				GeomType:          layerGeomType,
 				DontSimplify:      bool(l.DontSimplify),
+				DontClip:      	   bool(l.DontClip),
 			})
 		}
 

config/config.go

@@ -61,6 +61,9 @@ type MapLayer struct {
 	// DontSimplify indicates wheather feature simplification should be applied.
 	// We use a negative in the name so the default is to simplify
 	DontSimplify env.Bool `toml:"dont_simplify"`
+	// DontClip indicates wheather feature clipping should be applied.
+	// We use a negative in the name so the default is to clipping
+	DontClip env.Bool `toml:"dont_clip"`
 }
 
 // GetName helper to get the name we care about.

config/config_test.go

@@ -132,7 +132,8 @@ func TestParse(t *testing.T) {
 					provider_layer = "provider1.water"
 					min_zoom = 10
 					max_zoom = 20
-					dont_simplify = true`,
+					dont_simplify = true
+					dont_clip = true`,
 			expected: config.Config{
 				TileBuffer:   env.IntPtr(env.Int(12)),
 				LocationName: "",
@@ -180,6 +181,7 @@ func TestParse(t *testing.T) {
 								MinZoom:       env.UintPtr(10),
 								MaxZoom:       env.UintPtr(20),
 								DontSimplify:  true,
+								DontClip:  true,
 							},
 						},
 					},

maths/validate/validate.go

@@ -96,6 +96,8 @@ func scaleMultiPolygon(p tegola.MultiPolygon, factor float64) (bmp basic.MultiPo
 	return bmp
 }
 
+// CleanGeometry will apply various geoprocessing algorithems to the provided geometry.
+// the extent will be used as a clipping region. if no clipping is desired, pass in a nil extent.
 func CleanGeometry(ctx context.Context, g tegola.Geometry, extent *geom.Extent) (geo tegola.Geometry, err error) {
 	if g == nil {
 		return nil, nil

mvt/feature.go

@@ -15,7 +15,7 @@ import (
 	"github.com/go-spatial/tegola/maths"
 	"github.com/go-spatial/tegola/maths/points"
 	"github.com/go-spatial/tegola/maths/validate"
-	"github.com/go-spatial/tegola/mvt/vector_tile"
+	vectorTile "github.com/go-spatial/tegola/mvt/vector_tile"
 )
 
 // errors
@@ -87,15 +87,15 @@ func NewFeatures(geo tegola.Geometry, tags map[string]interface{}) (f []Feature)
 }
 
 // VTileFeature will return a vectorTile.Feature that would represent the Feature
-func (f *Feature) VTileFeature(ctx context.Context, keys []string, vals []interface{}, tile *tegola.Tile, simplify bool) (tf *vectorTile.Tile_Feature, err error) {
+func (f *Feature) VTileFeature(ctx context.Context, keys []string, vals []interface{}, tile *tegola.Tile, simplify bool, clip bool) (tf *vectorTile.Tile_Feature, err error) {
 	tf = new(vectorTile.Tile_Feature)
 	tf.Id = f.ID
 
 	if tf.Tags, err = keyvalTagsMap(keys, vals, f); err != nil {
 		return tf, err
 	}
 
-	geo, gtype, err := encodeGeometry(ctx, f.Geometry, tile, simplify)
+	geo, gtype, err := encodeGeometry(ctx, f.Geometry, tile, simplify, clip)
 	if err != nil {
 		return tf, err
 	}
@@ -570,7 +570,7 @@ func (c *cursor) ClosePath() uint32 {
 
 // encodeGeometry will take a tegola.Geometry type and encode it according to the
 // mapbox vector_tile spec.
-func encodeGeometry(ctx context.Context, geometry tegola.Geometry, tile *tegola.Tile, simplify bool) (g []uint32, vtyp vectorTile.Tile_GeomType, err error) {
+func encodeGeometry(ctx context.Context, geometry tegola.Geometry, tile *tegola.Tile, simplify bool, clip bool) (g []uint32, vtyp vectorTile.Tile_GeomType, err error) {
 
 	if geometry == nil {
 		return nil, vectorTile.Tile_UNKNOWN, ErrNilGeometryType
@@ -592,7 +592,12 @@ func encodeGeometry(ctx context.Context, geometry tegola.Geometry, tile *tegola.
 	if err != nil {
 		return nil, vectorTile.Tile_UNKNOWN, err
 	}
-	ext := geom.NewExtent([2]float64{pbb[0], pbb[1]}, [2]float64{pbb[2], pbb[3]})
+
+	// check if we need to clip and if we do build the extent
+	var ext *geom.Extent
+	if clip {
+		ext = geom.NewExtent([2]float64{pbb[0], pbb[1]}, [2]float64{pbb[2], pbb[3]})
+	}
 
 	geometry, err = validate.CleanGeometry(ctx, sg, ext)
 	if err != nil {

mvt/feature_internal_test.go

@@ -83,7 +83,7 @@ func TestEncodeGeometry(t *testing.T) {
 
 	fn := func(tc tcase) func(t *testing.T) {
 		return func(t *testing.T) {
-			g, gtype, err := encodeGeometry(context.Background(), tc.geo, tile, true)
+			g, gtype, err := encodeGeometry(context.Background(), tc.geo, tile, true, true)
 			if tc.eerr != err {
 				t.Errorf("error, expected %v got %v", tc.eerr, err)
 			}

mvt/layer.go

@@ -56,6 +56,8 @@ type Layer struct {
 	DontSimplify bool
 	// MaxSimplificationZoom is the zoom level at which point simplification is turned off. if value is zero Max is set to 14. If you do not want to simplify at any level set DontSimplify to true.
 	MaxSimplificationZoom uint
+	// DontClip truns off clipping for this layer.
+	DontClip bool
 }
 
 func valMapToVTileValue(valMap []interface{}) (vt []*vectorTile.Tile_Value) {
@@ -84,7 +86,7 @@ func (l *Layer) VTileLayer(ctx context.Context, tile *tegola.Tile) (*vectorTile.
 
 		simplify = simplify && tile.Z < l.MaxSimplificationZoom
 
-		vtf, err := f.VTileFeature(ctx, kmap, vmap, tile, simplify)
+		vtf, err := f.VTileFeature(ctx, kmap, vmap, tile, simplify, !l.DontClip)
 		if err != nil {
 			switch err {
 			case context.Canceled: