'$RCSfile: eml-spatialReference.xsd,v $'
Copyright: 1997-2002 Regents of the University of California,
University of New Mexico, and
Arizona State University
Sponsors: National Center for Ecological Analysis and Synthesis and
Partnership for Interdisciplinary Studies of Coastal Oceans,
University of California Santa Barbara
Long-Term Ecological Research Network Office,
University of New Mexico
Center for Environmental Studies, Arizona State University
Other funding: National Science Foundation (see README for details)
The David and Lucile Packard Foundation
For Details: http://knb.ecoinformatics.org/
'$Author: obrien $'
'$Date: 2009-02-25 23:51:54 $'
'$Revision: 1.41 $'
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eml-spatialReference
Schema for validating spatial referencing descriptions.
This module defines both projected and unprojected coordinate systems for
referencing the spatial coordinates of a dataset to the earth. The schema is based on
that used by Environmental Systems Research Inc (ESRI) for its .prj file format. EML provides a library of
pre-defined coordinate systems that may be referred to by name in the horizCoordSysName element. A
custom projection may be defined using this schema for any projection that does not appear in this
dictionary.
all spatial entities
yes
Spatial Reference Description
The system used to reference spatial locations to a
coordinate system
A spatial reference description provides the
information for relating the positional information in a spatial
dataset to real-world locations. A description typically includes
identification of a reference datum, a spheroid definition, and
projection algorithm. It also provides any constants required by that
algorithm.
Horizonal Coordinate System Name
The name of a predefined coordinate system
The name of a coordinate system for which a definition has been
provided in the eml-spatialReferenceDictionary.xsl file.
NAD_1927_StatePlane_Arizona_Central_FIPS_0202
Horizonal Coordinate System Definition
The definition of a coordinate system
Terms and parameters necessary to define a geographic or projected coordinate
system for horizonal distances.
Vertical Coordinate System Definition
The reference frame or system from which vertical
distances (altitudes or depths) are measured.
Altitude System Definition
the reference frame or system from which
altitudes (elevations) are measured.
The term "altitude"' is used instead of
the common term "elevation" to conform to the terminology
in Federal Information Processing Standards 70-1 and
173.
Altitude Datum Name
The identification given to the surface
taken as the surface of reference from which
altitudes are measured.
WGS_datum
Altitude Resolution
The minimum distance possible between
two adjacent altitude values, expressed in Altitude
Distance Units of measure.
1
Altitude Distance Units
Units in which altitude is
measured.
1
Altitude Encoding Method
The means used to encode the
altitudes.
Depth System Definition
The reference frame or system from which
depths are measured.
Depth Datum Name
The identification given to surface of
reference from which depths are
measured.
Depth Resolution
The minimum distance possible between
two adjacent depth values, expressed in Depth
Distance Units of measure.
Depth Distance Units
The units in which depths are
recorded.
Depth Encoding Method
The means used to encode
depths.
Datum
The point on the earth representing the origin for the geographic
coordinates to which the coorinate system is related to.
WGS_1984
Spheroid
An ellipse that is used to model the earth's surface.
An ellipse is used to define a idealized surface that ignores variation in elevation.
Spheroid name
The name of the spheroid.
Bessel 1866
Semi-axis Major
The larger of two orthogonal axes that define the ellipse
Meter
Prime Meridian Name
The name of the Prime Meridian
Greenwich
Longitude
The longitude of the Prime Meridian
0.0
Unit
The unit of angle by which coordinates are expressed.
degrees
Unit Name
The name of the unit of measure .
Degrees
Geographic Coordinate System
The coodinate system used to express the geographic
coordinates.
Projected Coordinate System
The coodinate system used to express planar coordinates.
Geographic Coordinate System
The coodinate system used to express the geographic
coordinates.
Projection
The method used to tranform between geographic and planar coordinates.
Parameter
A parameter required by the projection method.
Most projections require one or more parameters to control the
orientation and positon of the projected coordinate plane.
Parameter Name
The name of the parameter.
If the paramter corresponds to one that has been
defined in the existing eml-SpatialReferenceDictionary, then that name should be
used to enhance recogonizability.
False_Easting
Parameter Description
A description of the Parameter.
An offset by which x origin has been adjusted,
expressed in projection units
Parameter Value
The value supplied for the parameter
500000
Projection Unit
The unit of measure coordinates are expressed in.
Projection Unit Name
The name of the unit of measure.
Meter
Projection Name
The name of the projection method.
EML does not attempt to document the details
of the particular projection algorithm. It is incumbent on metadata provider
to ensure that the meaning of the names used to identify the method and its parameters will be
as clear as possible.
Transverse_Mercator
Horizonal Coordinate System Definition
The definition of a coordinate system
Terms and parameters necessary to define a geographic or projected coordinate
system for horizonal distances.