## georeferencing systems

##### DM-50 - Linear referencing systems
• Describe an application in which a linear referencing system is particularly useful
• Explain how the datum associated with a linear referencing system differs from a horizontal or vertical datum
• Identify several different linear referencing methods (e.g., mileposts, reference posts, link and node) and compare them to planar grid systems
• Identify the characteristics that all linear referencing systems have in common Unit GD4 Datums (core unit) “Horizontal” datums define the geometric relationship between a coordinate system grid and the Earth’s surface, where the Earth’s surface is approximated by an ellipsoid or other figure. “Vertical” datums are elevation reference surfaces, such as mean sea level.
• Explain how a network can be used as the basis for reference as opposed to the more common rectangular coordinate systems
• Discuss the magnitude and cause of error generated in the transformation from linear to planar coordinate systems
##### DM-48 - Plane coordinate systems
• Explain why plane coordinates are sometimes preferable to geographic coordinates
• Identify the map projection(s) upon which UTM coordinate systems are based, and explain the relationship between the projection(s) and the coordinate system grid
• Discuss the magnitude and cause of error associated with UTM coordinates
• Differentiate the characteristics and uses of the UTM coordinate system from the Military Grid Reference System (MGRS) and the World Geographic Reference System (GEOREF)
• Explain what State Plane Coordinates system (SPC) eastings and northings represent
• Associate SPC coordinates and zone specifications with corresponding positions on a U.S. map or globe
• Identify the map projection(s) upon which SPC coordinate systems are based, and explain the relationship between the projection(s) and the coordinate system grids
• Discuss the magnitude and cause of error associated with SPC coordinates
• Recommend the most appropriate plane coordinate system for applications at different spatial extents and justify the recommendation
• Critique the U.S. Geological Survey’s choice of UTM as the standard coordinate system for the U.S. National Map
• Describe the characteristics of the “national grids” of countries other than the U.S.
• Explain what Universal Transverse Mercator (UTM) eastings and northings represent
• Associate UTM coordinates and zone specifications with corresponding position on a world map or globe
##### DM-47 - Geographic coordinate system
• Distinguish between various latitude definitions (e.g., geocentric, geodetic, astronomic latitudes)
• Explain the angular measurements represented by latitude and longitude coordinates
• Calculate the latitude and longitude coordinates of a given location on the map using the coordinate grid ticks in the collar of a topographic map and the appropriate interpolation formula
• Mathematically express the relationship between Cartesian coordinates and polar coordinates
• Calculate the uncertainty of a ground position defined by latitude and longitude coordinates specified in decimal degrees to a given number of decimal places
• Use GIS software and base data encoded as geographic coordinates to geocode a list of address-referenced locations
• Locate on a globe the positions represented by latitude and longitude coordinates
• Write an algorithm that converts geographic coordinates from decimal degrees (DD) to degrees, minutes, seconds (DMS) format
##### DM-49 - Tessellated referencing systems
• Describe the octahedral quarternary triangulated mesh georeferencing system proposed by Dutton
• Discuss the advantages of hierarchical coordinates relative to geographic and plane coordinate systems
##### DM-50 - Linear referencing systems
• Describe an application in which a linear referencing system is particularly useful
• Explain how the datum associated with a linear referencing system differs from a horizontal or vertical datum
• Identify several different linear referencing methods (e.g., mileposts, reference posts, link and node) and compare them to planar grid systems
• Identify the characteristics that all linear referencing systems have in common Unit GD4 Datums (core unit) “Horizontal” datums define the geometric relationship between a coordinate system grid and the Earth’s surface, where the Earth’s surface is approximated by an ellipsoid or other figure. “Vertical” datums are elevation reference surfaces, such as mean sea level.
• Explain how a network can be used as the basis for reference as opposed to the more common rectangular coordinate systems
• Discuss the magnitude and cause of error generated in the transformation from linear to planar coordinate systems
##### DM-49 - Tessellated referencing systems
• Describe the octahedral quarternary triangulated mesh georeferencing system proposed by Dutton
• Discuss the advantages of hierarchical coordinates relative to geographic and plane coordinate systems
##### DM-48 - Plane coordinate systems
• Explain why plane coordinates are sometimes preferable to geographic coordinates
• Identify the map projection(s) upon which UTM coordinate systems are based, and explain the relationship between the projection(s) and the coordinate system grid
• Discuss the magnitude and cause of error associated with UTM coordinates
• Differentiate the characteristics and uses of the UTM coordinate system from the Military Grid Reference System (MGRS) and the World Geographic Reference System (GEOREF)
• Explain what State Plane Coordinates system (SPC) eastings and northings represent
• Associate SPC coordinates and zone specifications with corresponding positions on a U.S. map or globe
• Identify the map projection(s) upon which SPC coordinate systems are based, and explain the relationship between the projection(s) and the coordinate system grids
• Discuss the magnitude and cause of error associated with SPC coordinates
• Recommend the most appropriate plane coordinate system for applications at different spatial extents and justify the recommendation
• Critique the U.S. Geological Survey’s choice of UTM as the standard coordinate system for the U.S. National Map
• Describe the characteristics of the “national grids” of countries other than the U.S.
• Explain what Universal Transverse Mercator (UTM) eastings and northings represent
• Associate UTM coordinates and zone specifications with corresponding position on a world map or globe
##### DM-47 - Geographic coordinate system
• Distinguish between various latitude definitions (e.g., geocentric, geodetic, astronomic latitudes)
• Explain the angular measurements represented by latitude and longitude coordinates
• Calculate the latitude and longitude coordinates of a given location on the map using the coordinate grid ticks in the collar of a topographic map and the appropriate interpolation formula
• Mathematically express the relationship between Cartesian coordinates and polar coordinates
• Calculate the uncertainty of a ground position defined by latitude and longitude coordinates specified in decimal degrees to a given number of decimal places
• Use GIS software and base data encoded as geographic coordinates to geocode a list of address-referenced locations
• Locate on a globe the positions represented by latitude and longitude coordinates
• Write an algorithm that converts geographic coordinates from decimal degrees (DD) to degrees, minutes, seconds (DMS) format