International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
p 1990 image
p 1996 image
LF 25.13 mLF | 25.51 1
Elementary Composite Elementary Composite
objects objects objects objects
mean mean
LC PLAND |LCM |PLAND|SD |LC |PLAND|LCM |PLAND|SD
class |in % class |in 96 in 96 | class| in 96 class |in 96 in 96
.89
HLF 127.85 mHLF | 26.99 |2.08
SH 24.60 mSH [24.95 |0.52
AG 14.77 mAG | 15.44 0.96
GR. [6.13 mGR | 5.62 0.79
WA 10.37 mWA | 0.18 0.14
RI 1.35 mRI 1.32 0.02
CL 0.00 - -
LF 12125 ImLFE |2126 243
HLF'|16:30 [mMHLF| 1225 1238
SH [33.99 | msH | 3820 |360
AG 114.53 |mAG |1440 |0.74
GR [11.40 | mGR | 11.60 |2.57
WA | 1.17 mWA | 1.00 0.13
R 1.29 mRI 1.29 0.03
CL. 0.00 - -
Table 1: Elementary objects versus composite objects expressed in cover percentages (PLAND) for respectivelv the land cover
classes (LC) and land cover mosaic classes (LCM); the latter are based on the mean PLAND values resulting for the 14 different
MA values (p1990 image and p1996 image).
the smallest elementary object up to the largest composite
object. In addition, the values should also include the
minimum -area of tree covered land that should be considered
as ‘forest’, which ranged from 0.01 ha in the Czech Republic to
100 ha in Papua New Guinea (Lund, 1999). During the
sensitivity analysis, the LCM parameter mix was kept constant
(BN=0.55). A total of 28 LCM classifications were carried out
on two Landsat TM images of the Pelangkaraya study area of
1990 and 1996 further referred to as p1990 and p1996.
Five methods were selected to evaluate the LCM -classification
results, the standard remote sensing accuracy method KHAT
(Congalton and Mead, 1983) and four Landscape Pattern
Metrics as applied in landscape ecology (Forman, 1995;
McGarigal et al., 2002). The discrete multivariate analysis
technique KHAT and the Zstatistic for significance testing are
used to evaluate the overall classification results (Hudson and
Ramm, 1987). The elementary objects are used as reference to
calculate the similarity matrices. The Landscape Pattern
Metrics were used to evaluate the LCM classification results on
variability and arrangement of forest cover and forest cover
pattern. The metrics Percentage of Landscape (PLAND) and
Number of patches (NP) evaluate forest cover, whereas the
metrics Simpson 's Diversity Index(SIDI) and Landscape Shape
Index (LSI) evaluate forest cover pattern. PLAND and SIDI are
spatially independent metrics, which refer to composition or
variability of the landscape, or ‘how different things are’. NP
and LSI are spatially dependent metrics, which refer to the
configuration or arrangement of the landscape. or ‘how things
are distributed’ (Forman, 1995; Gustafson, 1998).
3. RESULTS
3.1 LCM classification results
Figure 4 shows the LCM classification results for two different
values for minimum area, i.c., MA is 25 ha and 300 ha, for the
p1990 image (with BN=0.55). For comparison, figure 5 shows
a standard per-pixel classification result uing the maximum
likelihood classifier. Figure 4 clearly shows that LCM
classification results provide crisp maps. In addition, the LCM -
classification with the larger minimum-area results in fewer
small objects; it is more aggregated.
Table 1 shows the classification results of elementary objects
versus composite objects expressed in cover percentages (i.e.,
PLAND). Overall, both aggregation levels show similar
ranking of major and min or classes. For the p1990 image, there
792
Figure 4: LCM-classification results for the p1990 image; MA
is 25 ha (a), and MA is 300 ha (b), both with BN at 0.55.
is almost no difference («196 cover) in PLAND values between
the two aggregation levels for all thematic classes. However,
for the 1996 image two striking differences (= 4% cover) exists
for the thematic classes related to heavily logged forest and
shrub. From 1990 to 1996, shrub vegetation and grass
vegetation have enormously increased, reducing the vegetation
of heavily logged forest. The increase of grass vegetation is
depicted by both aggregation strategies meaning that grass
tends to occur in (homogeneous) clusters. However, the
increase of shrub is differently depicted by both aggregation
strategies meaning that shrub tends to be (heterogeneously)
distributed over the landscape. This finding supports the fact
that shrub is an intermediate vegetation between the transition
of forest to agriculture and vice versa.
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