I am loading senate district polygon shapefiles from https://www.census.gov/cgi-bin/geo/shapefiles/index.php?year=2019&layergroup=State+Legislative+Districts into my Leaflet map. Well, to be accurate, I am first converting these shapefiles to GeoJSON with mapshaper.org. Anyway, we would like to color individual districts based on statistics such as income level. However, the shapefiles do not contain district IDs.
Are the polygons in these shapefiles organized in a consistent sequence that can be mapped to district IDs?
If not, is there another way to know to which district each polygon corresponds?