Friday, January 26, 2018

Vector Tile (Basemap Series Part 3)

My two previous posts concerned about tile layers served as basemap in raster format. Tile layer in raster format is superb because it is deliver fast reading, great compatibility between systems and standards, Tile layer in raster format is also works for any kind of data and independent from the source data format. Either you have thematic maps in vector format or satellite imagery/DEM in raster format, Tile layer in raster could handle them well.

But technology always changing. In recent years, development of tile layer in vector format got its fruition. It is somewhat better than raster, but it is not dedicated to replace the raster based tiles. It has specific function which is mainly to serve basemap in VECTOR format.

By using vector format, you can get :
1. Smaller file size to serve, so higher performance is guaranteed.
2. Dynamic and good resolution/display in every scale or zoom level (vector ftw man).
3. Faster generation and processing time compared to raster.
4. No artifacts or jagged features due to resolution limitation like we commonly found on raster.
5. And the most important is, points are stored in points, line stored in line, polygon stored in polygon, and label stored in font (not pixels). In this way, vector tile enable the user to change the symbolization or label format of the tiles according to their needs. This is the feature that raster based tiles couldn't do.

The limitation of vector tiles is of course they can't server data sources stored in raster format like satellite imagery or Digital Elevation Model.

You can make vector tile using online cloud GIS provider like Mapbox, or ArcGIS pro.

Here is an example to authorize vector tile using ArcGIS pro and hosted under ArcGIS online.

1. Load up your map and its final symbolization and labeling in ArcGIS pro.

2. Open Geoprocessing tools > Data Management Tools > Packages , To make proper vector tile, you must make first the tile index, so open the Create Vector Tile Index Tool. Set it up according your needs, and go.

3. Now the tiles creation, load up Create Vector Tile Tool, and make your tiles, dont forget to set the tile index created from previous step as the index polygons. The output will be saved in VTPK format.

4. After it is done, upload the created data to ArcGIS Online under organization account (public account is not working). You can apply trial to ESRI if you dont have access to ArcGIS online subscription. Here is how the map looks in ArcGIS online. 

I will continue the tutorial about how to change the symbolization of vector tile in next post, stay tuned.

Btw, here is a LINK which all tools and theoretical background about vector tiles currently has been developed