Geographic Coordinate Systems

Preferred by State Governmenets:
Geographic (Latitude/Longitude or Decimal Degrees)
Universal Transverse Mercator (UTM)
State Plane Coordinate System (SPCS)
Other
Albers Equal-Area Conic Projection - Used by the USGS in their 1970 National Atlas.

Glossary

DEM

Digital Elevation Model (USGS)

DGPS

Differential GPS 3-5 m. accuracy

DLG

Digital Line Graph

DOQ

Digital Orthophoto Quadrangles

DQQ

Digital Quarter Quadrangle

DTM

Digital Terrain Model (USGS)

DXF®

is the Drawing eXchange Format from AutoCAD

GIS

- Geographic Information System - A system of hardware, software, and procedures for drawing and analyzing maps and data referenced by spatial or geographic coordinates. Becoming a standard for government projects.

GPS

Global Positioning System (Tutorial at trimble.com)

HPGN

- High Precision GPS Network High Accuracy Reference Network (HARN) or High Precision Geodetic Network (HPGN) - HARN and HPGN are both names for the same project that is focused on readjusting the NAD83 datum to a higher level of accuracy state by state.

NAD27

North American Datum 1927 - State Plane Feet -

NAD83

North American Datum 1983 - State Plane Meters -

NAPP

National Aerial Photography Program (USGS)

NDOP

National Digital Orthophoto Program (USGS)

NGS

- National Geodetic Survey - Defines and manages a national coordinate system. This network, the National Spatial Reference System (NSRS), provides the foundation for transportation and communication; mapping and charting;

NADCON

- the federal standard for NAD27 to NAD83 datum transformations within the United States.

NADCON conversions between datums are approximate values based on models of real data. A regular grid of control points whose datum shifts are known is used to estimate the shift at other locations. A minimum curvature-derived surface based upon the National Geodetic Reference System determines the transformation of points and introduces approximately 0.15 meters uncertainty (at the 67% confidence level) within the coterminous United States.4 The accepted national standard, NADCON is the fastest, simplest, and most accurate datum transformation for mapping at scales of 1:200 and smaller.

NADCON only converts geographic (latitude and longitude) coordinates. The method cannot be applied directly to projected coordinates, such as State Plane.

See ftp.ngs.noaa.gov/pub/pcsoft/nadcon/readme.txt
NADCON software is available at: http://www.ngs.noaa.gov/PC_PROD.

NOAA

- National Oceanic & Atmospheric Administration

NSRS

National Spatial Reference System

NRCS

- U.S. Natural Resource and Conservation Service (gis.itc.nrcs.usda.gov)

SPCS

State Plane Coordinate System

SDTS

Spatial Data Transfer Standard

TVP

Topological Vector Profile

USGS

- U.S. Geological Survey - Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment.

UTM

- Universal Transverse Mercator

WAAS

Wide area augmentation system (or sites) for GPS (< 3m. accuracy)

WGS 84

World Geodetic System - Used by GPS systems. Adopted from NAD 83. For all practical purposes there is no difference between WGS 84 and NAD 83.

Map Symbols

See Also:

Sources:
North Carolina GIS Technical Advisory Committee Position Paper