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SAE J2735-Draft-Rev29 [issued: 12-11-08]
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259 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
km INTEGER (1..5000)
} --# UNTAGGED
}
1
2
3
Valid Region
Valid Range
of Heading
Figure 7: Circular Region
Polygon Region
While the circular region is simple, its shortfall is that it is too inclusive. In the example below, exit
services (gas, food, and lodging) are to be advertised at an exit ramp on an interstate highway. If a large
circular region was used, vehicles on Crescent Blvd would also present the exit service message. Even
with the use of the direction field, access roads would still erroneously display the message. In this
example, eight points are used to display a polygon region that encompassed I-96 but excludes Crescent
Blvd.
DCK Note: Chris: this does the exact same thing that the current draft allows in the shape point set of the
valid region (except that the anchor need not be part of the point set), and its not really a closed surface (a
polygon). You don’t need it. Did you really want to support a true polygon (a collection of connected point
to form a closed surface)? Made no changes in the std from this.
ASN.1 Representation:
[CH41] Polygon ::= SEQUENCE { -- Polygon Description (limited to 12
vertices)
anchor
position3D,
--anchor of polygon
numOffsets
Integer(0..32),
offsets
SEQUENCE (SIZE(1..32)) OF
Offsets
--each offset describes the next in-order
--vertex around the polygon as referenced
--to the anchor point.
}
Offsets ::= SEQUENCE {
xOffset
INTEGER (-32768..32767),
-- long offset in meters
yOffset
INTEGER (-32768..32767), -- lat offset in meters
sOffset
INTEGER (-32768..32767) OPTIONAL -- elev offset in meters
},