Columbia, 1990) is acceptable as a primary 
source of that data and, with the addition of 
features specific to MacMillan Bloedel’s 
needs (cadastre, forest inventory), will form 
a new spatial database for the GIS. 
Hardware and software were acquired that 
will facilitate loading, enhancing and revising 
of the TRIM data while maintaining accuracy 
and topological integrity. 
2. FOREST BASE MAPPING 
2.1 Traditional Forest Mapping Procedure 
Annual revision of the mapbase is an 
important function as MacMillan Bloedel 
harvests approximately 10,000 hectares of 
forest each year and the resultant land 
changes (new roads and cutblocks) must be 
added. Although this process is a corporate 
requirement, the responsibility for 
documenting these changes rests with each 
of the ten individual woodlands divisions. 
These divisions have traditionally used time- 
consuming field sketching techniques to 
update paper copies of the current mapbase 
that may or may not reflect the previous 
revision period(s). There has not been any 
standardized compilation techniques or 
understanding of data quality at this level. In 
addition, the logistics of coordinating the 
data sources, acquiring the data and creating 
source documents for digitization has been 
complicated and labourious. This method for 
performing the annual Inventory Revision has 
been identified as inadequate for the current 
mapbase and is totally unsuitable for the new 
spatial database. Aerial photography has 
never been implemented as an annual data 
source due to the cost and difficulties in 
coordinating flights over such a large area. 
2.2 Forest Mapping and Satellite Remote 
Sensing 
Satellite imagery, both optical and radar, has 
been identified as a viable data source for 
MacMillan Bloedel's map revision for a 
number of reasons. Firstly, the precise 
correction of satellite data to acceptable 
accuracies for operational mapping has 
become possible due to the availability of the 
448 
digital TRIM data, especially the Digital 
Elevation Model (DEM). Secondly, the 
proposed revision process, by the very nature 
of the data source and its unique handling 
requirements, will be a centralized process 
with standardized compilation techniques 
performed by personnel with an appreciation 
for data quality and integrity. Thirdly, spatial 
coverage of the imagery will allow updating of 
large areas in one session at a considerably 
lower cost than with aerial photography. 
Fourthly, the re-visit capabilities of the 
satellites will permit revision on a more timely 
basis. Lastly, radar imagery in particular will 
permit all-weather acquisitions. This is an 
important factor as many of MacMillan 
Bloedel's operating areas are affected by the 
cloud and fog conditions that are typical of 
British Columbia's west coast climate. 
The methodologies developed will allow 
MacMillan Bloedel to revise it's new spatial 
database in an economic and timely manner 
with an accuracy that, while not necessarily 
to TRIM mapping specifications, will be a 
known quantity that can be documented and 
applied to the decision making process. As 
satellite data spatial resolution improves, data 
compiled at less than the ideal specification 
can be replaced. 
3. DATA SETS 
Remote sensing data were collected over 
Louise Island in the Queen Charlotte 
Archipelago (52?56'N, 131?45'W). The data 
set consists of satellite Synthetic Aperture 
Radar (SAR), airborne SAR, simulated satellite 
SAR (using airborne SAR as input data), and 
satellite optical data. 
The optical data set includes four bands of 
imagery from the French SPOT satellite. 
SPOT satellites carry two high resolution 
visible imaging systems (HRV). Each HRV 
system has two imaging modes: 1) the 10m 
spatial resolution panchromatic mode (PLA) 
with a spectral range of 0.51 to 0.73 um; 2) 
and the multi-spectral mode (MLA) operating 
in 3 bands at 20 m spatial resolution and 
spectral ranges of 0.50 to 0.59 ym, 0.61 to 
0.68 um and 0.79 to 0.89 um. For the 
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