Implement lazy loading mechanism

[rtodea]

From what we can tell, we will need:

1. a tile server (i.e. zoom/x/y.{format} endpoints)
2. a smart way to integrate the real-time functionality with the ArcGIS tile layer

Tile server

We will need:

1. cliping logic
2. convert to the correct format (e.g. GeoJSON)

Caching mechanism is out of scope for now.

ArcGIS integration

Investigate the tile layer capabilities:

1. https://developers.arcgis.com/javascript/latest/api-reference/esri-layers-TileLayer.html

[rtodea]

After reading the documentation for VectorTileLayer there are new formats that need to be understood:

• Mapbox Style Specification
• TileJSON Specification at root/sources/sourceKey

  Client                                    Server

VectorTileLayer    +------------------>  /mapbox-style-spec.json

                   <------------------+

                        +----
                        |   ++
                        |    | MapboxStyleSpec.json
                        |    |
                        +----+

                   +------------------>  /{zoom}/{x}/{y}.pbf

Simplest TileJSON spec:

{
  "type": "vector",
  "tiles": [
    "http://a.example.com/tiles/{z}/{x}/{y}.pbf",
    "http://b.example.com/tiles/{z}/{x}/{y}.pbf"
  ]
}

[rtodea]

Tile Servers that might be used:

1. tilestrata
2. tilelive ecosystem ?
3. use mapnik + parsers + generators listed by Mapbox

Tilestrata

For tilestrata you need to use an existing plugin for vector tiles: tilestrata-vtile or create your own

Problems with tilestratata-vtile:

1. tilestrata-vtile uses a path to the mapnik XML config
2. we can use an utility to convert a GeoJSON to an XML style sheet: geojson-mapnikify

By writing your own provider you need to better understand the interface.

Raw implementation

GeoJSON ----> Mapbox Vector Tile (VT) ----> PBF
        geojson-vt                    vt-pbf

References:

1. vt-pbf
2. discussion on how to update a vector tile