NGS Enabling Historical “T-Sheets” to be Accurately and Efficiently Geo-referenced

NGS Enabling Historical “T-Sheets” to be Accurately and Efficiently Geo-referenced

Historical Topographic Sheets (“T-Sheets”) produced by the U.S. Coast and Geodetic Survey are referenced to various horizontal datums in use over the two hundred years since the first Survey of the Coast in 1816.

To use these maps to document coastal change, a conversion has to be made from the horizontal datum used at the time the map was published to the datum in which modern data are expressed.

Upon successful completion of rigorous testing now underway, the National Geodetic Survey (NGS) will soon provide a free horizontal datum transformation tool for use by the general public, allowing users to be more self-sufficient and freeing up NOAA resources from responding to numerous requests for technical support.

The completion of this task will greatly increase the value of historical NOAA charts to the public. This effort will support a myriad of historical coastal change analysis.

For example, scientists investigating coastal archaeological sites will now have more accurate positions and coastal geomorphologists will have better tools to document shoreline change over time. For more information, contact Cindy Craig.

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