Vector tiles vs raster tiles – the pros and cons

Base maps provide us with the foundation to visualise and analyse data using the ArcGIS platform. But with a range of options now available, have you ever wondered if you’re using the right base map within your solution?

Technology’s rapid evolution is driving the need to utilise fast rendering tiles, which is why vector seems to be getting all the coverage these days. However, raster tiles remain very useful for many tasks and workflows.

So vector or raster? There is a place for both types of tiles. Making the right decision as to what’s best for you and your customers really comes down to your specific needs.

VECTOR

Pros:

  • Tiles are rendered quickly and are only 20-50 per cent the file size of raster tiles. For example: to generate vector tiles of an Esri world basemap takes approx. eight hours on a desktop machine, and tiles are 13 gigabytes in size
  • More tiles can be produced per second
  • Less bandwidth is needed due to the smaller size of tile packages – making vector tiles a better choice when streaming to devices
  • Map styles (colour, grey, night mode, etc.) can be changed without needing to download more information or other tile sets
  • Dynamic labelling allows size and font types to be changed on the fly

Cons:

  • Rendering occurs on the client side, where limited resources can hamper speed
  • Compromises clarity by reducing display detail
  • Requires ArcGIS Pro – not supported in ArcMap
  • Requires OpenGL/WebGL/DirectX support, which is an issue for some mobile devices
  • Certain products (e.g. Collector for ArcGIS, Geocortex) don’t yet support vector tiles
  • Not suitable for imagery or other raster maps
  • Vectors are generalised (i.e. not raw data) so they may not be suitable for editing

RASTER

Pros:

  • Tiles are generally rendered in advance on the server and streamed to the destination
  • Detailed tiles can be generated and served
  • More suitable for the display of imagery and shaded terrain

Cons:

  • Can be CPU and memory consuming. For example: to generate raster tiles of an Esri world basemap in a single style would take many weeks on a server cluster, and tiles are 20 terabytes in size
  • Not the greatest for real-time rendering
  • Each map style must be created in a separate raster tile set
  • Labelling is pre-set and cannot be changed

So, to sum it up – think of vector tiles as being similar to image tiles. Instead of prerendered and styled roads, rivers, national parks, etc., each vector tile is a compressed binary file containing all the actual data needed to render the area it represents.

The amazing thing about all this is you are rendering and styling a ton of data on the fly, but this is done on the client side.

Raster tiles, meanwhile, are generated on the server side. So, if you want to save time on the client side, raster tiles are generally a good option, as they’re rendered in advance and streamed to the destination.

But really, it all depends on what application or solution you’re incorporating the tiled data into, because the dynamic labelling allows size and font types to be changed on the fly. It’s a matter of choice, but with the technology to both generate and consume tiles readily available you at least have options.

If you’d like to discuss the pros and cons of vector and raster tiles further, call +61 2 8436 2800 and ask to speak with a MapData Services data specialist.

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