Geovisualization Developer's Guide

Markers

Markers on a map represent elements that are tied to a location. These could be static objects such as buildings or dynamic events such as earthquake locations. The typical use case for markers is to associate information in a data visualization to specific locations on the map and display them meaningfully.

Markers are configured with two basic elements:

  • Marker data – location and filtering of the queried data
  • Marker style – color, shape and optional 'clustering' (the representation of markers indicating more than one data point at the same location)

Markers can also be designed to be proportional, where their features vary according to the variations in the data being represented. You can use differences in marker size, color, and transparency to illustrate the relative values within the dataset. For example, a marker representing an earthquake magnitude can be larger for stronger earthquakes and smaller for weaker ones.

Geovisualization allows you to create different kinds of markers; see Drawing Data-Driven Markers for details.

The following are examples of markers created with Geovisualization. Click the images to view the full code for these examples.

Figure 1. A map showing the location, magnitude and depth of earthquakes using proportional markers (click the image to go to the code example)
Figure 2. A map showing clusters of antennae using proportional markers (click the image to go to the code example)