The NYPL Map Warper (maps.nypl.org/warper) allows us to digitally align historic maps with the contemporary street grid, enabling a comparison of information from historic maps with that from a current map. Rectified maps are digitized historic maps that have been digitally aligned with geographic coordinates. Browse rectified maps by location, or search by keyword or name. Not all of the maps we have seen have been digitized, and not all digitized maps have been rectified. Rectifying historic maps is a public project; anyone can create an account and rectify historic maps. Sounds fun – why not give it a try?