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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
1. INTRODUCTION
The Global Positioning System (GPS) is an all-weather, space-
based navigation system. The real time kinematic (RTK)
positioning is one of the most popular topics in civilian
applications. Normally, RTK can be used to collect the land use
change information successfully and quickly. However, RTK
doesn’t work due to the overhead obstructions, such as in urban
areas or under trees. Then, all conventional terrestrial survey
methods, such as total station (TS), can be used to aid RTK.
Since the collected land use change information using either
RTK or total station system will be entered to an existed land
management system. Hence, the land use change styles of the
interested region could be classified into a certain number of
groups from the point view of Geographic Information System
(GIS). In order to reduce the field surveying works of RTK
and/or total station (TS), it is necessary to design an optimized
and effective field surveying procedure by means of analyzing
the land use change styles and environmental characteristics of
the interested region.
The following issues will be addressed in this paper: (1)
performance comparisons between using RTK and using total
sation system on land use data capture and updating in terms
of accuracy, speed, etc., (2) land use change styles analysis on
the interested regions. The campus of NCCU was selected as a
test region to test the performances of applying RTK and/or
total station system on land use change data collection. The
cadastral maps (on different times) of Mu-Za district of Taipei
City were analyzed to find the possible land use change styles.
The section 2 will introduce the basic concept of integrating
RTK and TS on land use change data collection. The concept
of land use change style analysis will be given in section 3. The
lest procedures and test results will be described and presented
in section 4, and some conclusions based on the tests results
will be given in section 5.
2. INTEGRATING RTK AND TS FOR LAND
SURVEYING
Real time kinematic (RTK) surveying, as implied by its name,
enables positions of points to be determined instantaneously as
the roving receiver (or receivers) occupies each point (Wolf &
Ghilani, 2002). Real time kinematic surveying requires that two
(or more) receivers be operated simultaneously. The unique
aspect of this procedure is that radios are used to transmit
corrections to the roving receiver. One receiver occupies a
reference station and broadcast raw GPS observations to the
roving unit (or units). At the rover, the GPS measurements
from both receivers are processed in real-time by the unit's on-
board computer to produce an immediate determination of its
location. Because point positions with high accuracy are
immediately known, real time kinematic surveying is capable
for construction stakeout. It is also convenient for locating
details for mapping and for many other surveying tasks.
Although it has so many advantages compared to conventional
terrestrial survey methods, RTK has some limitations. For
examples, in cases of failing to track sufficient amount of GPS
satellites due to the overhead obstructions, RTK doesn't work.
Then, those conventional terrestrial survey methods, such as
total station (TS), can be use to aid RTK.
Total station (TS) instruments combine an EDM (electronic
distance measurement), an electronic digital theodolite, and a
Computer in one unit. These devices automatically measure
horizontal and vertical angles, as well as distances, and transmit
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the results in real time to a built-in computer. The horizontal
and vertical angles and slope distance can be displayed, and
then upon keyboard commands, horizontal and vertical distance
components can be instantaneously computed from theses data
and displayed. If the instrument is oriented in direction and the
coordinates of the occupied station are input to the system, the
coordinates of any point sighted can be immediately obtained.
This data can all be stored within the instrument, or in an
automatic data collector, thereby eliminating manual recording.
The practical procedures of integrating RTK and TS on land
surveying: (1) using RTK to determine the coordinates of the
rover station; (2) using TS to determine the coordinates of the
rover station in cases of RTK doesn't work.
The procedures of using TS to determine the coordinates of the
rover station in cases of RTK doesn't work are as follows: (1)
assumed that the rover station is point A and the RTK doesn't
work at point A; (2) then choosing two points (P, Q) around A
that will be used as control points in TS surveying; (3)
determining the coordinates of P and Q points using RTK; (4)
determining the coordinates of point A using TS.
3. ANALYSIS ON LAND USE CHANGE STYLES
Since the collected land use change information using either
RTK or total station (TS) system will be entered to an existed
land management system. Hence, the land use change styles of
the interested region could be classified into a certain number
of groups from the point view of Geographic Information
System (GIS). On the other hand, in order to reduce the field
surveying works of RTK and/or total station, it is necessary to
design an optimized and effective field surveying procedure by
means of analyzing the land use change styles and
environmental characteristics of the interested region.
Basically the land use change styles consist of varied shapes of
polygons. It is better to define the concepts of parent-polygon
and children-polygon. For example, a polygon Y is divided into
two polygons Y1 and Y2. Then, relative to Yl and Y2, polygon
Y is called the parent-polygon of Y1 and Y2 polygons, And,
Y1 and Y2 are called the children-polygons of polygon Y.
Accordingly the land use change styles can be classified into
two groups: (1) one parent-polygon is divided into several
children-polygons, and there is no border merging relationship
between parent-polygon and children-polygons; (2) one parent-
polygon is divided into several children-polygons, and there is
border merging relationship between parent-polygon and
children-polygons (Lin, 2003).
Group 1 can be classifiéd further into four styles: island style,
biscuit style, ring style and full style (Figure 1). Group 2 can be
classified further into three styles: two-way extension style,
one-way extension style, and merging style (Figure 2). Letters
A, B, C, etc. in Figure 1 and 2 denote the varied land use styles.
4. TEST RESULTS AND DISCUSSIONS
4.1 The Land Use Change Style Analysis of Urban Area
The general land use change styles are introduced in section 3.
In order to further understand the land use change styles of
urnan areas of Taiwan, the cadastral maps (on different times)
of Mu-Za district of Taipei City were analyzed.
