----------------------------Original message---------------------------- I have the DMA MIL SPEC MIL-H-89201A for all HAC products. Paragraph 3.3.1 states that horizontal accuracy is 1.0 mm at chart scale. Hopes this helps. > -----Original Message----- > From: Courtney Schumacher [SMTP:[log in to unmask]] > Sent: Tuesday, March 17, 1998 1:02 PM > To: [log in to unmask] > Subject: DMA standards and accuracy > > ----------------------------Original message---------------------------- > Hello, > > I sent the below message to NIMA who pointed me toward NOAA and from > whom I haven't heard yet. The map librarian at the University of > Washington suggested I direct my questions toward this listserve. > > I'm curious about DMA map accuracy in the central/western, tropical > Pacific. A meteorological research project that my group is involved > with is underway in the Marshall Islands. We have 17 rain gauges > between 7-9.5 N and 166-169 E. A GPS receiver was recently sent out to > get exact lat/lons of the gauges, however, the GPS unit at times > disagreed with DMA nautical maps of the area (map numbers: 81030, > 81715, 81723, 81557, 81737). The largest disagreement was almost 20 km > but in general the discrepancies were on the order of a km. What is > the DMA standard for island locations on their nautical maps? Are the > locations accurate to within a km? I understand that there could have > been errors in the GPS readings but I'm trying to bound the possible > error of the DMA maps. Any information or references would be > appreciated! > > Thanks, > Courtney Schumacher > > -- > --------------------------------------------------------------------- > Courtney Schumacher INTERNET: [log in to unmask] > Dept of Atmospheric Sciences > Box 351640 TEL: (206)685-1073 > University of Washington > Seattle, WA 98195-1640 > ---------------------------------------------------------------------