processors are so powerful that speeds in excess of
10,000 points per minute are achieved despite the
complex, multiple pass nature of the Hierarchical
Relaxation Correlation which is still the basis of the
module (Helava, 1988).
While small improvements such as bicubic resampling
and change detection from radiometric differences
between orthophotos derived at different epochs, may
affect more users, the most dramatic innovation on the
orthophoto scene has been "true orthos", i.e. orthophotos
with correction for building lean. The layered
mosaicking with user defined seam lines and both
geometric and radiometric feathering has been retained,
but much faster, more highly automated mosaicking is
available too. Current work includes an inference engine
for determining DTM strategies for the user, refinement
of the recent implementation of iterative orthophoto
refinement (Norvelle, 1994) and a totally automated
sequence from raw imagery through to final mosaic,
which works well with satellite data. The output of
image maps has been enhanced too, particularly with a
PostScript option that enables lines and text to be output
at higher resolution than the background image in order
to take full advantage of variable inkjet, laser plotter and
film writer devices.
While perspective scenes and fly throughs have been
commonplace in the remote sensing world for several
years, they are now acquiring the status of useful
photogrammetric products and their application has
emerged from the military world and found a natural
home in the planning world (Simmons, 1996).
3.2.6 Feature extraction. Undoubtedly, the
introduction of robust, practical semi-automated tools for
feature extraction has been a major innovation. Three
tools, for measuring roofs of buildings, for determination
of linear features and for region building, are offered, all
based on the principle of image processing to improve
approximate measurements made by the user. Early tests
with the roof tool indicate a significant improvement in
productivity compared to manual measurement,
accompanied by a noticeable reduction in fatigue.
Further tools in development include sophisticated
radiometric methods of detecting and measuring roads
and gabled roofs.
3.3 Other software
Two small modules have been added by Leica.
CONVERT is an important utility, which enables
orientation data to be transferred in both directions
between the DPWs and many analytical plotters. At the
conclusion of HATS, therefore, it is possible to have any
model available on a DPW immediately and on an
analytical plotter after inserting the plates and
performing interior orientation.
One of the strengths of SOCET SET has been the wide
choice of software packages available for map
compilation and GIS. Early dalliances with Kork, now
owned by Vision International, and Aviosoft MAPce,
have been superseded by strong links to a number of
extremely popular products. The well known Leica
PRO600 product providing an on-line link between
SOCET SET and Bentley Systems MicroStation is now
identical, except for the real-time portion, on the DPWs
and the analogue and analytical plotters. The automated
70
tools mentioned above are being added to PRO600 to
increase productivity. More recently, PRO600 has
acquired triangulated irregular network (TIN)
functionality, for sophisticated manipulation of DTMs,
in the form of TerraModeler, from the Finnish company
Terrasolid Oy, with which Leica has established a
strategic alliance. KLT’s ATLAS package is an
acknowledged leader for customers who do not wish a
CAD or GIS package as part of their map compilation
solution. This product has been specially modified and
refined to suit the DPWs. ATLAS has strong facilities
for TIN manipulation and has functions to import
SOCET SET DTMs for further processing. Moreover,
conditions in the market-place are such that it is sensible
to offer an open system and facilitate solutions including
competitors’ map compilation packages where customers
wish to retain these and avoid retraining or reformatting
costs. Thus Zeiss CADMAP and DAT/EM
DGN/CAPTURE are available in addition to the
products in Figure 2 and some customers also are
working on integration of their map compilation
software.
On-line links to GIS packages exist for Unisys System 9
and Clemessy GeoCity, the latter forming the basis of the
solution designed for IGN, Paris. At the time of writing,
work is in hand for a link to Leica’s INFOCAM GIS, but
in general terms the case for on-line LIS/GIS is not
established: an off-line relationship using CAD formats
and post hoc topology checks appears to be more popular
in practice. Work is in progress such that SOCET SET's
feature extraction module will be able to read and write
ARC/INFO coverage files directly.
3.4 Dual systems
Since 1994 it has been possible to combine the scanning
and workstation functions on a single SPARCstation
host. Thus organisations which do not need continuous
scanning can extract more value from their hardware.
One popular application on these dual systems is HATS.
4.0 USERS
The remarkable growth of digital photogrammetry since
the 1992 Congress in Washington is well known.
Customers range from smaller private companies with
one workstation to national mapping, organisations and
military survey departments with one or more scanners
and multiple workstations. Every installation is different,
which demonstrates how the systems business differs
from the analogue instruments of 30 years ago. While it
is not possible to discern completely clear trends, it is
true to say that some customers exploit most phases of
the digital photogrammetric process, but others
concentrate on one phase or another. For example, there
are numerous companies whose primary product is
image rather than line maps; and there are a few
scanning, bureaux, who offer only scanning services and
perhaps aerial photographic processing. Adoption of
digital photogrammetry as the primary tool for feature
collection has taken longer, but wider software choices,
better user interfaces and improvements in ergonomics
have encouraged greater use. Raster output has presented
new challenges too. Customers have published
extensively on their applications and, in some cases,
their use of SOCET SET's development tools to interface
to their own modules.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996
4.1 Use
Users pl
developt
worldwi
accruing
custome
opportut
purchas
therefor
includec
as conti
from the
many o
small, s
1C, Sw
describe
enhance
map foi
implem:
range m
manipul
demand
flexible
individu
keep ap:
4.2 Tha
While «
HATS :
over th
comput
systems
to give
the sca
continu
their us
continu
innovat
some c
Windov
SOCET
greater
automa!
manage
develop
systems
a rapid]
combin
of de
photog
The at
DSW3(
comme
historic
Dam, ,
mat
scai
€
Féd