When visualizing data on a map we can use from a static PNG file, through a vector format (e.g. SVG) to a world scale map service. Depending on the use case we will have to choose one option, another, or a hybrid.

For example, in [this web map](https://esridevevents.github.io/arcgis-platform-location-services-for-developers-2023/leaflet-geojson.html) you can see how **painting this 45MB JSON file with 34,980 polygons and +2 millions vertex, where each polygon has many vertices, in Leaflet and without optimization is not a good idea**.

In this session we will quickly review these options and then focus mainly on different techniques, tools and technologies that will help us to create faster and more interactive visualizations, especially in the most complex **scenarios where we need to visualize, explore and filter datasets that include tens or hundreds of thousands of graphical elements that can occupy GBs in a fast and agile way**.

Some of these techniques and tools are:
- Tessellation (raster & vector)
- Aggregation (clustering, heatmaps, binning, ...)
- Cartographic generalization (e.g. simplifying lines/polygons by reducing the number of vertices)
- Scale controls
- Format transformation (e.g. TopoJSON)
- ...

During the session we will see and use several technologies that will allow us to perform such optimizations, although to illustrate most of the optimizations we will use JavaScript and a free account [ArcGIS](https://developers.arcgis.com/). However, practically everything we will see is applicable to any other programming language and other technologies.

This session is introductory so only basic knowledge of JavaScript is required.