Introduction

The National Register Information System (NRIS) is a database of over 84,000 historic buildings, districts, sites, structures and objects listed on, removed from, or pending listing in the National Register.

Documentation

Hi. The data files were compressed into two archive files, DETAIL.EXE, a coded file of information specific to properties in the NRIS and MASTER.EXE, a file containing the codes and decodes used in NRIS (to save space). You may or may not want to preserve the "coded" nature of the data. Together these archives contain the necessary collections of files you will need to query the data to import it into other databases or to write your own, non-trivial, queries.

The data files have been put into a normalized, non-proprietary format--fixed length dBASE III Plus (.dbf) files for putting into a PC-database of your choice. SCHEMA.DBF tells you what files and fields are available to you. There are only two kinds of data files here--the property-specific detail information in the detail.exe information and the code and decode files master files in master.exe. In DETAIL.EXE all the one to one relationships are in a single main file while the remaining files in detail.exe contain all the one to many relationships. Link the detail files to each other on the basis of the unique reference number or refnum and then link the files in detail .exe to master.exe on the basis of the code and decodes. You may, of course, use all or only selected data files, depending upon your need. Many users may prefer to work with a subset of the data, for example a particular state.

To use the data, the first thing you should do is to transfer the files on your diskette to a directory on your hard disk. Next type DETAIL.EXE followed by MASTER.EXE. You should now have all the "raw data" you need. Typically you would make a file of unique reference numbers for the subset of interest and then use this file to extract the information from all of the other files in detail.exe. For example, if you are interested in just a particular state then go to the countyd.dbf file and build a file of reference numbers where statecd is equal to the state of your choice (select the nonblank primary flag, or primeflg <> ' '--this eliminates the duplicates that could occur since one property can be in many counties). You may also want to filter out properties that are not listed and have, for example, a pending or removed status. If you want only listed properties make sure you select propmain.certcd='LI' only (the complete list of code and decodes is in certm.certcd). Now you have a file of unique reference numbers available that allows you to extract attributes from all the related one to many files joined on the basis of the reference number such as apcritd.dbf (applicable criteria) and archtectd.dbf (architect). Feel free to take what you want and throw the rest away. The file date of detail.exe indicates the currency of the data. A simplified version of the data can be found in the Simplified and Spatial_data folder. Note that these fields have also been translated to the more generic Dublin core format in our NPS Focus imaging application at nrhp.focus.nps.gov but that format is not represented here.

John Byrne
Database Manager
National Register of Historic Places
John_Byrne@nps.gov