SOURCE/CONVERSION METHODOLOGY

Two foot contour were developed by Intermap Technologies Corporations, 2000.
The ground control surveys was base on Massachusetts State Plain Coordinate,
North America Datum of 1983 horizontally and the National Geodetic Vertical Datum
of 1988 vertically. Differential GPS and combination of static and RTK methodologies
were used. The ground controls meet FGCC Second Order Class II accuracy standard.
Thirty ground control points were established
The aerial triangulation meets the accuracy requirements of RMSE values of 15 microns
on pass and tie points and 20 microns on control points.
The digital terrain model was compiled on stereoplotters and suitable for the
production of the 2 foot contours. The topographic accuracy is such that 90%
of elevations are within One half the contour interval and 90% of spot heights
are within four tenths on the contour interval. Break lines were compiled
along all street centerlines, along all railway tracks and along all water
courses. Break lines were also compiled at all significant breaks in slope
be they natural or man-made.
Contours are tiled in 49 individual tiles.

COVERAGE NAME

a1  to g1

FEATURE TYPE

LINE

ATTRIBUTES

Feature Attribute Table Organization:

COORDINATE SYSTEM

Massachusetts State Plane North America Datum (NAD) 83 Feet