Why don’t all geometries show on every zoom level?
In the Drive’s web viewer you may find that not all of your geometries are shown on every zoom level. Here is why your geometries may get ”down sampled”:
In 2D mode we keep scraping a random selection of geometries until reaching your browser’s memory limit when using Leaflet. If your data set includes under 8.000 geometries, we retrieve and display all of them right away. If your data set includes over 8.000 geometries we retrieve 4.000 and keep doing so as you navigate across the map.
Why do we use these upper bounds? Well, when exceeding these, Leaflet can slow down dramatically and crash your system. As such, a limit needs to exist because your browser can’t handle an endless amount of geometries. In 3D mode, that uses three.js instead of Leaflet, this limit is much, much higher (to accommodate point clouds for example).
Choose what is shown on each zoom level
Having discussed the (rather technical) reason that not all geometries are shown at every zoom level, we can talk about how you can control which geometries do show up!
In settings you can choose which geometries to include in each zoom level when making the random selection of geometries to display. This allows you to, for example, show large geometries when zoomed out, and show smaller ones when zoomed in.
A great example of this is how roads are often displayed on online maps. When zoomed out you may only see highways, when zooming in, secondary and tertiary roads start showing up.
This way, you can create a very structured view of your data, while never losing out on performance.