AAPG Map Publication Standards

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AAPG Map Publication Standards
Purpose To insure that features on published map
s can be accurately located and that maps and
imagery may be digitally merged.
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So, whats the problem?
First, many maps do not contain enough coordinate
ticks or grid lines to scale and orient the map.
Second, rarely is there a good enough descript
ion of the map parameters to uniquely reproduce
the map.
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Technical Issues

• Datums
• Map Projections
• Grid Coordinates

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Datums
Most longitude and latitude values are tied to
ground surveying. These points not generally on
the same datum (reference frame) as GPS
locations. (The same point can have more than one
correct longitude and latitude.)
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Map Projections
Maps are systematic representations of a round
earth on flat paper, and as such cannot be equal
scale everywhere. The map projection and the
projection origin describe how the scale varies.
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Grid Coordinates
UTM Zone 15N
Hundreds of local coordinate systems (x and y
locations) are used by surveyors and map makers
throughout the world. Each is keyed to a specific
projection and has a specific origin.
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Proposed Standards
Published maps should include a graphic scale and
a north arrow. The accompanying text, or title
block, should provide enough information to allow
georeferencing. The information should include
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1) Projection type, and projection parameters
(unless it is a common, documented projection).
2) Scale at projection origin. 3) Internal or
marginal ticks or grid labeled with coordinate
or grid values. 4) If X,Y coordinates (other t
han UTM or State Plane) are used, grid origin,
false Easting and Northing, and units of
measure. 5) Geodetic datum.
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Note that a few grid and projection types are
well enough known that "NAD-27, Texas State
Plane, Central Zone" or "Europe50, UTM, zone 32"
are sufficient to completely characterize the map
projections.
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Exceptions

• Index or location maps that contain no
  significant scientific information.
  
• 2) Maps reproduced from earlier publications for
  which no reliable projection information is
  available.
  
• 3) Sketch maps (generally they should include a
  north arrow and scale).
  
• 4) Mine maps (generally a north arrow, scale bar
  and local grid if available).
  
• 5) Global maps (projection type is generally all
  that is necessary to reproduce the map).