![]() If you are attempting to serve this data on demand each time you need a tile you have to simplify and clip a potentially massive polygon. For example take a very detailed coastline of a large lake that is very precise and you are wanting to serve this dynamically. If you are dynamically serving tiles from PostGIS it is very hard to reduce large quantities of data quickly in some cases. The problem is that doing these steps is often very complex and requires thought about the cartography of your final resulting map, but it can also drastically effect performance. For each tile at each zoom level Select your data following your hierarchy rules, simplify your data based on your zoom level (for example you might need less points to display your road) and then clip your data to your tile and encode it to your Vector Tile. For example if you are talking about roads at some zoom levels you will want to see only highways or major roads while at other zoom levels you will want all your data.Ģ. The general steps for turning raw data into Vector Tiles are:ġ. ![]() Most of this provided speed and cache-ability is specifically gained by preprocessing all the data you will use in your map into tiles. The Vector Tiles specification was designed for map visualization but has expanded into other uses as well, but in general the purpose is to be able to quickly provide a complete subset of data for a specific area that is highly cacheable. Author of Mapbox's Vector Tile specification here and also contributor to some of the code that is used by PostGIS and I wanted to add some additional clarity on some topics associated with Vector Tiles and dynamic serving of them that seems to be a new trend. ![]()
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