8.0 Changing Technologies

Presently, there are new data collection and processing technologies
available that offer considerable improvements over traditional methods.
These include developments in integrated Global Positioning
System/Geographical Information System, soft-copy photointerpretation,
and data loggers with automated forms.

Furthermore, it is anticipated that over the life of the mapping
program, additional and perhaps dramatic improvements in technology will
occur. These new technologies offer the potential of cost savings and,
in some cases more useful output or products. Nevertheless, new
technology always presents risks that must be considered and then
managed.

8.1 Integrated GIS/GPS and Data Loggers

One of the more promising new technologies is the automation of field
data collection using integrated GIS/GPS. The convergence of GPS and GIS
and document management technologies and the arrival of rugged and
portable computers provide new means of collecting field data. Portable
GIS with GPS will allow the rapid capture of information about features
and phenomena, and the ability to map them in the field. The
incorporation of automated forms packages and data logging software can
speed data capture using menus and pick lists with predefined features,
attributes, and space for numeric, or character value entry. (i.e.,
hydrologic regime or aspect). These automated forms packages can be
customized with mathematical macros to perform some functions that would
require a calculator, such as relative abundance calculated
automatically by entering the species occurrence along a transect. These
data can be automatically tagged to a GPS coordinate via connections to
GPS receivers. Data collection templates can also be designed for quick
transfer to relational databases or any SQL DBASE format. It is
recommended that a data logging system built from off‑the‑shelf hardware
and software be tested during the prototype stage. For additional
discussion of GPS technology see **Section 7.1** in the Accuracy
Assessment Methodology document.

8.2 Digital Orthophotography

The use of digital orthophotography (soft copy) in the
photointerpretation process is also a very promising technology. It is
still considered developmental for many applications, but recent
advances have pushed it to the point where an investment in testing and
evaluation is warranted.

Digital orthophotos are terrain-corrected images that can be used as
precision basemaps, or they can be viewed on a screen as
three-dimensional digital images for extracting and delineating features
through a manual or partially automated process. The process involves
scanning a film positive and then rectifying the image to a dense
network of known points on a pixel-by-pixel basis. The digital terrain
model (DTM) can be generated automatically in many systems following the
standard photogrammetric steps of obtaining ground control and
performing aerotriangulation. However, automated DTM feature extraction
is far from perfected and it is often necessary to manually add
breaklines and edit the DTM.

Once the orthophoto is created, it can be viewed on the screen in three
dimensions (stereo) using special glasses, much like a mirror
stereoscope except the display is heads-up and the operator can draw the
digital line work directly on the image using a puck. Land base
information can be added as well as thematic information. The advantages
of the process are that certain steps, such as the transfer of line work
and digitization of line work, are accomplished as the interpretation
proceeds. It also means that the final products are highly accurate as
the number of steps are reduced and the method is essentially
photogrammetric. Additionally, if the original DTM is sufficiently
dense, and the vertical as well as the horizontal control are field
surveyed, then accurate NMAS topographic information, in the form of
contours, can also be generated. This does mean additional expense.

Some of the disadvantages are the initial high cost of the software and
hardware and the large size of the files created, particularly those
associated with high resolution. Additionally, using the orthophoto for
the land base means the polygon information will, in all likelihood, not
register with other existing digital data tied to a USGS quadrangle
without some manipulation. This could be a factor in the design of an
overall multipurpose GIS.

However, the most basic concerns are whether photointerpretation can be
accomplished as accurately on the screen as with the original
diapositives and a high-powered mirror stereoscope, and does the use of
the process significantly reduce total man-hours for a positive cost
benefit ratio? It is proposed that these questions be tested during the
prototype stage.

8.3 Strategy for Implementation of New Technology

The basic strategy for dealing with changing technology during the NPS
mapping contract is to develop standards that will stand independently
of the technology. That is to say the standards will not dictate how
something is to be accomplished but rather define the content, accuracy,
and documentation of the product. This will ensure that data being
derived from the new technologies will not affect the utility of the
existing data. Secondly, as new, promising technology becomes available,
it will be evaluated first in benchmarks and then in prototype efforts
to gauge its reliability, its cost-effectiveness, and, most importantly,
whether or not it can perform to the documented standard.