Now that you've gone through a walkthrough and built your own tiled map, hopefully your appreciation has increased for the amount of cartographic design and effort required for producing a web basemap. In this week's assignment, you'll look at some existing tiled maps, then get some practice building your own.
Do the following:
- Find four online maps that use tiled maps in the background. These can be either rasterized image tiles or vector tiles. For each map, comment on where the tiles are coming from and how they were produced, if you can figure it out. It's okay if some of your tile providers are repeated (for example, two of the four might use Google Maps), but try to find at least one web map that uses a "homegrown" tiled basemap in the background. Simple local map viewers produced by city and county GIS websites are good places for this.
- Create a tiled map of rasterized images using some or all of your term project data. Depending on the nature of your data, this can be a basemap or a map with several thematic layers that is designed to overlay a basemap.
You should design this map using QGIS and upload it to your AWS S3 bucket, following the same procedures we used in the 2nd walkthrough. The map should be designed using sound cartographic principles, including aesthetically pleasing colors, an intuitive visual hierarchy, and a useful labeling scheme. Take advantage of scale-dependent rendering settings on your layers and the option of working with multiple copies of the same data set, so that the user is not overwhelmed with information at any particular scale. Zooming into the map should reveal progressively more information.
Important: Be careful with how many levels of tiles you build for this assignment, in particular if your project area is very large. Our recommendation is to keep the total size of the tile set that you are going to upload to S3 below 250MB, definitely below 500MB, and below 30,000 tiles in total (you can remove the subfolders for higher zoom levels after you produced the tiles to reduce the total size). As you saw in the walkthrough, if the project area is very small like a large city, a maximum zoom level of 17 should be ok. If your project area is an entire state in the U.S., try out what total sizes you get if you for maximum zoom levels between 12 and 14. If your project area is the entire U.S. (or a similar area), try out maximum zoom levels between 10 and 12. Also, if your tiled map consists of thematic layers, make sure the tile background is transparent, so that the tiles can be overlaid on top of other layers.
Please produce a report containing all the information requested in the first bullet above, as well as a URL to your tileset in your AWS S3 bucket so that I can test in a web map as shown in the walkthrough, together with a few words on how you designed your tiles so that I know what to look for. Then submit the report to the Lesson 5 drop box on Canvas.