Use animated pulsating marker for time series sample location

[j08lue]

We need to make a change to the sample location marker on the globe, so it looks less like a buffer (we are only sampling point values, not zonal statistics).

Design

The marker needs to draw attention on a background with busy colors, invite users to move it, and have affordance for touch devices.

Design proposal: 48x48px target crosshair, animated pulsating dot

Implementation

1. Are animated GIFs or a CSS/SVG solution currently possible? https://community.esri.com/t5/arcgis-javascript-maps-sdk-questions/animated-picturemarkersymbol/td-p/419275
2. Or do we need to go WebGL? https://developers.arcgis.com/javascript/latest/sample-code/custom-gl-visuals/

The solution needs to work well on mobile.

[j08lue]

Authoritative info from ESRI:

• WebGL with a CustomRender node seems to be the only viable option with the current version
  • https://developers.arcgis.com/javascript/latest/sample-code/custom-render-node-windmills/
  • https://developers.arcgis.com/javascript/latest/sample-code/custom-gl-visuals/
• Animated gifs & pngs are currently supported in 2D maps, but not 3D maps
• SVG animations are not supported in either 2D or 3D yet
• A 2D animated symbol API is in beta and coming very soon for the JS SDK, 3D support will be further off