# Map components¶

The components that provide an API interface to the geospatial visualizations are described here. Greppo uses Leaflet to render and interact with geospatial data. The main components are:

## Base layer¶

This provides the base layer to be used. It is usually a link to a tile server. Although only one base layer could be visible at a particular time, you can add many base-layers as options that can be toggled in the app.

## Overlay layer¶

You can add as many overlay layers as you want. At this moment, only vector overlay layers can be added. Raster layers are forseen in the coming releases.

## Draw feature¶

Through the provided draw feature, you can draw Point, Line or Polygon on the map and can get the data of the drawn features using the app.draw_feature() API in your script as a GeoDataFrame. At this point you can have only one draw feature, but multiple draw features are foreseen.