For most T-sheets, all information shown on the T-sheet was digitized, except in some cases, primarily in the San Juan Islands, where mapping consistently extended considerably inland from the nearshore. In those cases, all information was digitized to 500 m inland of the nearshore, where "nearshore" is used as defined by the Puget Sound Nearshore Ecosystem Restoration Project:
"The estuarine/delta, marine shoreline and areas of shallow water from the top of the coastal bank or bluffs to the water at a depth of about 10 meters relative to Mean Lower Low Water. (This is the average depth limit of light penetration.) This zone incorporates those geological and ecological processes, such as sediment movement, freshwater inputs, and subtidal light penetration, which are key to determining the distribution and condition of aquatic habitats. By this definition, the nearshore extends landward into the tidally influenced freshwater heads of estuaries and coastal streams" (see <http://www.pugetsoundnearshore.org/whatwedo/Guidance.pdf>)
Some T-sheets contained consistent internal erroneous 'shifts' from the original surveyors. Shifts generally of more then 20 meters were adjusted for, by manually shifting features to correspond with identified modern day hard points and features on aerial photos that would not have substantially changed through time.
The attribute fields 'ADJUST' and 'ADJUST_DIST' identify areas that were adjusted along with the distance and general direction of the shift.