Philosophy Technological change occurs if it is necessary and when it is possible. The establishment of a digital national street centerline map by the federal government in the late 1970s, initially for census taking purposes, made it possible for conventional spatial information to migrate to the computer screen. The convenience introduced by digital street maps made it necessary for insurance, real estate information, banking, design build, dispatch, transportation, and land development disciplines to start using it to remain “competitive.” As it proved both possible and necessary, the digital street centerline emerged as the industry standard land base. Today, the street centerline is a powerful mandatory platform for routing and navigation operations. Address location is currently accomplished with dots along centerlines. As the customer base grows for the street centerline location platform, more are finding the locational accuracy of this method not meeting their expectations. At the same time, block-level spatial data emerged as the industry standard for urban and environmental analysis. Again, the broader the customer base for this technology the greater the expectation for increased detail and attributes only possible through the use of the parcel boundary at a national level rather than address points. So why isn't a national digital parcel boundary database already in place? Because its authorship is fragmented across over 3100 tax mapping authorities, each with its own format, projection, and data model structures. The National ParcelMap Data Portal makes it possible for you to conveniently obtain this vital content from a single source in a single data configuration for instant use. With much of the NPDP content updated quarterly, and the rest annually, NPDP is always the latest available content.