less accuracy. These latter classes also yielded a high agreement
with ground truth data (89.0%, 79.9% and 83.7%). The corresponding
percent commissions, however, were higher at 36.4% and 19.5%. Some
other classes, such as dense urban area and mixed and cultivated
fallow land, were more spectrally heterogeneous and had low overall
classification accuracies (58.7% and 53.2%) and high commission
percentages (27.2% and 58.0%).
These results indicated that classification became less accurate as
the level of detail was increased. The relatively low accuracies of
some categories at Level II could be attributed to cross-confusion
among related categories. To obtain more reliable information
regarding the land use and land cover classes, SPOT images from
several seasons would be necessary.
BACKGROUND DISCUSSION
Remote sensing and geographical information systems (GIS) are
important and advanced tools for the inventory and analysis of
natural resources for regional and local planning. Various types of
remote sensing data (MSS, TM, AVHRR, etc.) have been used for natural
resources management. Hill and Megier (1986) performed a digital
classification of the Ardeche region of southern France using Landsat
5 data as part of a region-wide resources inventory. Pettinger
(1982) performed a comprehensive digital classification of vegetation
and land cover in Idaho producing maps at different levels of detail
for natural resources management purposes. LaBash et al . (1989)
conducted a digital image analysis of Landsat TM data Tn eastern
Connecticut for regional land use and land cover classification.
Civco (1989) concluded that knowledge-based image analysis for
classifying Landsat Thematic Mapper region-based spectral data,
coupled with ancillary digital spatial information, not only is
feasible but also preferable to the per-pixel, spectral data only,
statistical methods more traditionally employed in deriving land use
and land cover information for natural resources management. This
approach produces results both more accurate and more visually
comprehensible than the traditional method of maximum likelihood
classification. Furthermore, SPOT HRV data are becoming widely
available and provide opportunities for increased spatial resolution
and temporal coverage for mapping. For example, the authors have
initiated a comprehensive land use planning study in the semi-arid
regions of northeastern Brazil using SPOT HRV data. Guebert et al.
(1989) concluded that in the geologic and climatic setting, it is
possible to characterize the infiltration capacities of disturbed
watersheds of central Pennsylvania by remotely sensed data.
Because of the relationships between infiltration capacity and
surface features observed by SPOT (vegetation and rock type),
infiltration can be generalized into low, moderate and high in
filtration capacity categories. These relationships hold for
surfaces of similar rock type and vegetation, although as climate and
rock type change, the magnitude of the relationship may vary.
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