PDF Mapping – Michael Bufkin - Adobe Acrobat and PDF for Architecture, Engineering, and Construction - page 203

Note: Read more about metadata in Chapter 13.
Adding Security
Like metadata, PDF allows the extensive use of security and digital signing techniques to prevent
unauthorized use of these documents. They are hidden from document display, but can provide invaluable
protections and assurances that the map intent and audience are served without exceeding those parameters.
Using Acrobat Navigation Features
As with many other electronic documents, maps in PDF can take much advantage of standard Acrobat
techniques for including bookmarks, hyperlinks and multimedia to generate systems of maps. These can be
used to create linked map topics which provide navigation between map tiles. Bookmarking can allow users
to select from many feature descriptions and automatically zoom to map locations. This can be extended to
street addressing, or the location of parcels, equipment, businesses and other features. Such geo-location
potential leads to a final set of issues that can provide an enormous extension to the utility of maps in PDF
format.
GIS Features for Maps in PDF
Beyond a static representation of a map in a PDF format, it is possible to use advanced cartographic
features to make the map a more intelligent document than the standard picture graphic (Figure 14.2).
Today, there are techniques that allow map users to display coordinates, measure distances and
directions, query and display feature data, geolocate objects, and connect directly to geospatial databases
through PDF forms or ODBC queries.
These advanced features are possible through PDF georegistration, a technique that embeds map
projection and coordinate transformation information directly in the PDF. The embedded information then
allows any point in PDF coordinates to be transformed directly to the coordinates of the system used to
create the map and vice versa . Knowing this relationship, any object or record containing a spatial
component can be accurately located within the PDF file, and any object in the PDF file can be located in
geodetic coordinates.
Georegistration extends the capabilities of a PDF map into areas which were previously only available
with complex GIS. If an object in a GIS has associated data, the data can now be associated with the same
object in the PDF and can be displayed by the user. Geocoding of addresses is accomplished by associating
a latitude and longitude of an address with a Go to a page action assigned to a bookmark. The action zooms
to a PDF point which has first been transformed from a lat/long to a PDF coordinate.
The availability of geodetic coordinates can allow outside applications to be used to obtain magnetic
declinations, or even point elevations. The combination of georegistered PDF and digital terrain models
(DTMs) will eventually allow the draping of the PDF image on the DTM to produce 3D imaging from the
map, viewed directly in Adobe Reader.
Best Practices
Given the many different software products used in the production of maps today, it is not possible to
provide a detailed guide for each. Maps are being made using products from Adobe, Autodesk, Avenza,
Bently Systems, Erdas, ESRI, Intergraph, GE Smallworld, Mapinfo, and others. Some of these products