Adobe Acrobat SDK
Interactive Features (Chapter 8 in PDF Reference)
Adobe® Supplement to the ISO 32000
8.8.1 Geospatial Features 49
When the value of the
Subtype
entry is
GEO
, the dictionary defines the relationship between points or
regions in the two dimensional PDF object space and points or regions with respect to an underlying
model of the earth (or, potentially, other ellipsoid objects).
Add the value of
GEO
to the
Subtype
entry of Table 8.110.
Between the two paragraphs that follow Table 8.110, insert the following.
When the subtype of a measurement dictionary is
GEO
, additional entries are defined. Table 8.111a,
page 50
, lists and describes these additional entries in a
geospatial measure dictionary
.
Add a new section to the end of Section 8.8.
8.8.1 Geospatial Features
PDF is a common delivery mechanism for map and satellite imagery data. In extension level 3, a geospatial
coordinate system is introduced (Table 8.110,
page 49
) along with a number of PDF constructs, as
explained in this section, to support geospatially registered content.
Geospatial Measure Dictionary
When the subtype of a measurement dictionary (Table 8.110,
page 49
) is
GEO
, additional entries are
defined through a
geospatial measure dictionary
.
A
geospatial measure dictionary
, Table 111a, contains a description of the earth-based coordinate system
associated with the PDF object, and corresponding arrays of points in that coordinate system and the local
object coordinate system. It may contain a bounding polygon (the
Bounds
entry), which defines the
region of the PDF object for which the geographic associations are valid. It may also contain a choice of
default units (the
PDU
entry) for user displays of positions, distances and areas. An optional display
coordinate system (the
DCS
entry) allows a document to be authored to display values in a coordinate
system other than that associated with the source data. For example, a map may be created in a state
plane coordinate system based on a 1927 datum, but it is possible to display its latitude and longitude
values in the WGS84 datum corresponding to values reported by a GPS device.
The entries of a geospatial measure dictionary are shown in Table 8.111a.
TABLE 8.110 Entries in a measure dictionary
KEY
TYPE
VALUE
Subtype
name
(
Optional
) A name specifying the type of coordinate system to use
for measuring. Valid values follow:
RL
, for a rectilinear coordinate system
GEO
, (
ExtensionLevel 3
) for a geospatial coordinate system
Default value:
RL
