001412L   0600049   22040000150000012815DQPA49430000;&HY01DQPA0100;&DDF RECORD IDENTIFIER1600;&POSITIONAL ACCURACYMODN!RCID!COMT(A,I,A)01608 R     00043   4104000100070DQPA15587     1DQPA     1Not Revised  Horizontal positional accuracy is based upon the use of USGS source quadrangles that are compiled to meet National Map Accuracy Standards (NMAS).  NMAS horizontal accuracy requires that at least 90 percent of points tested are within 0.02 inch of true position.  The digital data are estimated to contain a horizontal positional error of less than or equal to 0.003 inch standard error in the two component directions relative to source graphic.  Comparison to the graphic source is used as control to assess digital positional accuracy. Cartographic offsets may be present on the graphic source, due to scale and legibility constraints.  Digital map elements require edge alignment between data sets.  Data along each quadrangle edge are tested against the data set for the adjacent quadrangle using USGS processing software; tests check for positional accuracy between data sets within a 0.02 inch tolerance.  Features with like dimensionality that are within the tolerance are adjusted by moving the feature equally in both data sets.  Features outside the tolerance are not moved.  All disconnects are identified by edge matching flags that document the mismatch.  Not Revised  Vertical positional accuracy is based upon the use of USGS source quadrangles which are compiled to meet NMAS.  NMAS vertical accuracy requires that at least 90 percent of well defined points tested be within one half contour interval of the correct value.  Comparison to the graphic source is used as control to assess digital positional accuracy.  