A new take on Geobuf compact geospatial encoding format

geobuf2.proto

option optimize_for = LITE_RUNTIME;

message Data {

    message FeatureCollection {
        repeated Feature features = 1;
    }

    message Feature {

        oneof geometry_type {
            Geometry geometry = 1;
            GeometryCollection geometry_collection = 2;
        }

        repeated uint32 properties = 3 [packed = true];

        oneof id_type {
            string id = 4;
            uint32 uint_id = 5;
        }
    }

    message GeometryCollection {
        repeated Geometry geometries = 1;
    }

    message Geometry {

        enum Type {
            POINT = 0;
            MULTIPOINT = 1;
            LINESTRING = 2;
            MULTILINESTRING = 3;
            POLYGON = 4;
            MULTIPOLYGON = 5;
        }

        message LineString { // delta-encoded int coordinates
            repeated sint32 coords = 1 [packed = true];
        }
        message MultiLineString {
            repeated LineString line_strings = 1;
        }
        message MultiPolygon {
            repeated MultiLineString polygons = 1;
        }

        required Type type = 1;

        oneof coord_type {
            LineString line_string = 2; // Point, MultiPoint, LineString
            MultiLineString multi_line_string = 3; // Polygon, MultiLineString
            MultiPolygon multi_polygon = 4; // MultiPolygon
        }
    }

    message Value {
        oneof value_type {
            string string_value = 1;
            float float_value = 2;
            double double_value = 3;
            sint32 int_value = 4;
            uint32 uint_value = 5;
            bool bool_value = 6;
        }
    }

    oneof data_type {
        FeatureCollection feature_collection = 1;
        Feature feature = 2;
        GeometryCollection geometry_collection = 3;
        Geometry geometry = 4;
    }

    repeated string keys = 5;
    repeated Value values = 6;

    optional bool has_altitude = 7 [default = false];
    optional uint32 precision = 8 [default = 6];
}