VEGETATION COVER MAPPING
USING HYBRID ANALYSIS OF IKONOS DATA
Y. Hirose* *, M. Mori?, Y. Akamatsu* ,Y. Li b
? Kokusai Kogyo Corporation., Hino Technical Center, 3-6-1 Asahigaoka, Hino, Tokyo 191-0065 Japan —
(masaru_mori, yoko_hirose, yukio_akamatsu)@kkc.co.jp
? Japan Space Imaging Corporation, 8-1 Yaesu 2-Chome, Chuo-Ku, Tokyo 104-0028 Japan —
yunli@spaceimaging.co.jp
Commission VII, WG VII/3
KEY WORDS: Vegetation, High Resolution, /KONOS, Classification, Segmentation, Spectral, Texture, Remote Sensing
c
ABSTRACT:
Detailed mapping of vegetation cover types is often required in various environmental study projects. Very high-resolution satellites,
e.g. IKONOS, are expected to provide a new opportunity to make detailed vegetation cover maps efficiently for large study areas.
This paper reports the methodology of the vegetation cover mapping using IKONOS data for a watershed management project in
south-western Japan. In this study, we examined spectral, geometric, and textual properties of image objects extracted through both
object-based and pixel-based image classification of IKONOS panchromatic, mulit-spectral, and pan-sharpen images of the study
area to check whether vegetation cover types in the study area are distinguishable using IKONOS data. The result of the analysis
shows that, in conjunction with spectral information, textural and geometric information of image objects extracted from IKONOS
data provide useful information for detailed vegetation cover classification. Based on the analysis, we developed a multi-scale
object-based image analysis method for vegetation cover mapping using IKONOS data. Applying the multi-scale analysis to
IKONOS images, a vegetation cover map of the study area was obtained.
Table 1. Classification scheme of the vegetation map of the river
information data set and the summary of the classification result
of an IKONOS image via maximum likelihood classification
1. INTRODUCTION
In Japan, river environment information such as spatial
distributions of vegetation and wild life habitats along rivers has
been periodically collected by the ministry of land,
infrastructure, and transportation since 1990. Along with the
recent increase in concern over the restoration of the natural
environment in Japan, information contents of the river
information data set is now being reviewed by the ministry so
that it would be able to provide more useful information for
realizing environmentally appropriate watershed management.
The requirements for the new data sources of the river
information data, which would be an alternative for aerial
photo-interpretation and field survey, include cost-effectiveness,
continuity, periodicity, and objectivity. Very high-resolution
satellite images are expected be a useful information source for
acquiring vegetation information along major rivers in Japan,
which is part of the environmental data set.
This paper reports the tentative study of the vegetation cover
mapping from IKONOS data for a watershed management
project in south-western Japan, assuming the future use of
IKONOS data for the nationwide river information acquisition.
2. CLASSIFICATION SCHEME
Table 1 shows the classification scheme designed for the
vegetation mapping in this study. The right column of the table
summarizes the result of the tentative vegetation mapping from
IKONOS data using the maximum-likelihood classifier. Based
on the result, the vegetation mapping for the project seem to
need both object-based and pixel-based classifier.
286
(+: Acceptable, *: Moderate, -: Unacceptable)
Class
Results of maximum likelihood
classification of an IKONOS image
Water plant
+ Field check is necessary
Grass
+ Sometimes it is confusingly similar
to deciduous trees
Deciduous tree
+ Sometimes it is confusingly similar
to grasses
Coniferous tree
*Difficult to distinguish from bamboo
forests
Bamboo *Difficult to distinguish from
coniferous forests
Bush + Field check is necessary
Bare land + Relatively easy to identify
Orchard * Visual interpretation must be used
in conjunction with maximum
likelihood classification
Vegetable field
* Visual interpretation may be
needed to ensure the classification
results
Rice field
- Difficult to distinguish from
agricultural fields without imagery
taken at submerged period
Manmade
structure
* Distinction from residential area IS
problematic
Residential area
* Distinction from manmade
structures is problematic
Open water
+ Relatively easy to distinguish
Internatio
Ven
Ground re
patch SIZ
values a
distinguis
vegetatior
maximum
informati
individual
object-bas
well as s;
suitable 1
vegetatior
contiguou
and label
spatial re
and textur
In this s
from acti
of the Ni
western |
land use
forests ai