a TI Rs,
OBJECT-BASED CLASSIFICATION OF
IKONOS DATA FOR RURAL LAND USE MAPPING
M. Mori**, Y. Hirose*, Y. Akamatsu*, Y. Li®
* 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
KEY WORDS: Land Use, Object, Segmentation, IKONOS, Classification, Rural, Spectral, Texture
ABSTRACT:
Land uses in rural areas of Japan, which typically consist of small agricultural fields, complex vegetation covers, and sparsely
distributed residential arcas, have been problematic in terms of land use mapping using satellite remote sensing data due to the
complexity of the spatial structure. Increasing availability of very high resolution satellite (VHRS) data and the advancement of
object-based image classification techniques in recent years provide a new opportunity for mapping detailed land uses from space.
To utilize VHRS data and object-based image classification for creating land use maps, the correspondence between image objects
extractable from VHRS data and land use classes observable on the ground, based on the spectral, spatial, and contextual
relationships among image objects, must be established, because neither pixels nor segmented image objects of VHRS data directly
correspond to land use classes into which we want to classify geo-spatial features on the ground. In this study, we conducted
quantitative analyses of the spectral and spatial properties of image objects extracted from an IKONOS pan-sharpen image of a rural
town in southwestern Japan, and proposed a classification framework for detailed land use mapping. Firstly, we extracted image
objects from the IKONOS data using a multi-scale segmentation technique. Based on the statistical analyses of image objects, a
hierarchical classification scheme for object-oriented land use classification was proposed.
1. INTRODUCTION
Very high-resolution satellites (VHRS) including IKONOS
provide a useful way for us to periodically monitor detailed
land use in broad areas. Pixel sizes on the ground of VHRS
sensors are small enough to capture geometrical details of
common land use patches, and most geographic features on
VHRS images, which we want to map on land use maps, are
represented as clusters of multiple pixels. For mapping land use
from VHRS images, object-oriented classification methods
utilizing image segmentation and contextual rule-based
labelling techniques are expected to be more suitable than
traditional pixel-by-pixel classifiers (Blaschke, T., Strobl 2002).
To utilize VHRS data and object-based image classification for
creating land use maps, the correspondence between image
objects extractable from VHRS data and land use classes
observable on the ground must be established, based on the
spectral, spatial, and contextual relationships among image
objects, because neither pixels nor segmented image objects of
VHRS data directly correspond to land use classes into which
we want to classify geo-spatial features on the ground.
In this study, we conducted quantitative analyses of the spectral
and spatial properties of image objects extracted from an
IKONOS pan-sharpen image of a rural town in southwestern
Japan, and proposed a classification framework for detailed
land use mapping. Firstly, we extracted image objects from the
[KONOS data using a multi-scale segmentation technique.
Based on the statistical analyses of image objects, a hierarchical
classification scheme for object-oriented land use classification
was proposed.
2. LAND USE IN RURAL PARTS OF JAPAN
Figure 1 shows a schematic view of the land use pattern often
seen in the rural parts of Japan, depicted on a panchromatic
image taken from the IKONOS-2 satellite. A typical land use
pattern in rural parts of Japan consists of houses (usually with
backyards), agricultural fields (rice, wheat, etc.), forests, and
networks of roads.
In a macroscopic view, houses in a rural town in Japan tend to
aggregate in certain areas of the town, and form residential
areas. Residential areas are usually surrounded by agricultural
fields growing rice, wheat, vegetables, etc. The boundaries
between residential areas and agricultural fields are relatively
clear for human interpreters. Road networks are not in a grid-
like arrangement, and the shapes and sizes of parcels are not
uniform.
A house in the countryside usually has a backyard or a small
plot of ground for growing vegetables. That is, image objects
corresponding to the houses and agricultural fields in rural
towns in Japan share relatively similar constituents.
The relationship between houses and residential areas can be
seen as a hierarchical structure of the land use pattern in the
view of landscape ecology, and pixel-by-pixel-base image
classifiers hardly produce optimal land use maps without
intensive editing by human photo-interpreters.
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