Since the release of ArcGIS Pro 1.2 it has been possible to create vector tiles for data in the WGS 1984 Web Mercator Auxiliary Sphere coordinate system. However, at ArcGIS Pro 1.4 (December 2016), users can now also publish their data as vector tiles using local projections – for GB customers, this typically means British National Grid!
What are vector tiles?
Vector tiles contain vector representations of data across a range of scales. Unlike raster tiles, they can adapt to the resolution of their display device and even be restyled for multiple uses. They can be published to and consumed within ArcGIS Online or Portal for ArcGIS as a vector tile package .vtpk. Vector tiles can also be consumed in ArcGIS Pro.
Esri have already published nine global vector basemaps that can be used in web maps and web apps. It is also possible to create your own styles from vector basemaps without having to host or maintain the underlying data.
In this first of two posts, I will be walking you through the steps required to publish your own vector tiles using a local projection. The follow on post will examine the basemap customisation process in more detail.
Creating vector tiles
Before you begin, it’s important to ensure that your map is valid and efficient for vector tile creation. Here are a few of the key things to check:
- Vector tiles can be created from any map or basemap in ArcGIS Pro that contain point, line, polygon or multipoint features – any other layers must be turned off or removed altogether. Vector tiles cannot be created from a Scene.
- Ensure the map's metadata has been completed (the description field must be specified at minimum).
- Avoid complex symbology and symbol effects where possible. For example, features that contain hatched or gradient fills, markers along lines or polygon outlines will not be rendered properly in the resulting tiles.
- To reduce data density, consider generalising complex features. Some generalisation occurs automatically when you generate vector tiles but tools such as Simplify Building, Simplify Line and Simplify Polygon can help.
- Limit scale ranges – too many vertices at smaller scales can result in tiles that don’t perform quickly.
For more information on how to author a map for vector tile creation, you can read the ArcGIS Pro documentation here. To create my vector tiles, I authored a map containing OS Strategi data (which uses the British National Grid projection).
The easiest way to convert a map to vector tiles is by sharing it as a web layer. My methodology was as follows:
1. Highlight the map in the Contents pane.
2. On the Share tab, in the Share As group, click the Web Layer menu and click Publish Web Layer
3. In the Share As Web Layer pane, on the General tab, under the Layer Type heading, choose Vector Tiles.
4. In the Configuration tab, check the tiling scheme. In this demo, I am using the British National Grid tiling scheme (which was automatically suggested due to the data being used).
5. Hit Publish, sit back and let ArcGIS Pro take care of the rest! The output Vector Tile Package will automatically be uploaded and published to your active portal (ArcGIS Online/Portal for ArcGIS).
In the example below, you can see the OS Strategi Basemap I published in the ArcGIS Online map viewer. This layer can also be consumed in Portal for ArcGIS and ArcGIS Pro.
In the next post, I will show you how to create multiple different styles of this basemap, without the need to republish/maintain the underlying data!