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Proceedings International Workshop on Mobile Mapping Technology
Li, Rongxing

A. R. SILVA 1 , J. C. BATISTA 1 , R. A. OLIVEIRA 1 , P. O. CAMARGO 2 and J. F. C. SILVA 2
'Cartographic Engineering Undergraduate Program
2 Department of Cartography and Center of Mapping
Universidade Estadual Paulista - UNESP
19060-900 Presidente Prudente SP
KEY WORDS: surveying, mapping, terrestrial photogrammetry, street scenes, capstone project.
A 1:2000 street map was made based on a topographic surveying by photogrammetric traverse technique. Photogrammetric
traverse concatenates terrestrial stereo-pairs. The technique is suitable to map roads and streets surveyed by mobile mapping
system terrestrial platform. Two urban blocks were surveyed by photogrammetric traverse and a street map was made using
a collection of different equipment, hardware and software. Street images were acquired by a simple digital camera (Kodak
DC40) mounted on a tripod which was moved forward to simulate the vehicle trip along the streets. The same thing was
done to the antenna of the rover GPS receiver while the fixed receiver stayed on a reference station. The camera perspective
centers were positioned by GPS surveying and the orientation angles were computed by bundle block adjustment. GPS data
were processed by Ashtech Reliance vl.40. Digital images were processed by Kodak PhotoEnhancer vl.7 and by Zsoft
PhotoFinish v3.0 to extract image coordinates (then transformed to photocoordinates). A bundle block adjustment (tftc),
adapted to the particular geometry, computed the angular orientation and the coordinates of pass points and interest points.
Autodesk AutoCAD Map vl.O was used for map edition and Golden Software Surfer v6.0 interpolated the contour lines and
DTM. 10% significance level statistic tests show that the trend analysis and map accuracy succeeded. Accuracy resulted
around one meter approximately. This means the map may be classified as a class B map according to Brazilian
cartographic criteria. In this particular case, the standard error is 0.5mm in map scale.
The scientific and technical program of this workshop
demonstrates how developed are the mobile systems to
acquire spatial data for mapping and GIS (Geographic
Information Systems) purposes. However there are
situations that modem equipment lets a practical simulation
arises with two goals in perspective. One is to give students
the opportunity to merge distinct techniques in order to
make a topographic map and the other to observe and
analyze the results of applying distinct techniques under a
different and modem approach.
Particularly, we have decided to proceed with simulated
situations of collecting data on streets to make maps using
an alternative methodology called photogrammetric
traverse. The idea behind this project was to provide an
understanding of the map making process to a group of
undergraduate students (capstone project). Despite of being
an unconventional method for topographic mapping, the
project also brought contributions to learn the relationship
between the stages that connect the main phases of the data
and information when it comes to the application of
photogrammetric traverse.
Although simulating a mobile mapping platform acquiring
data, the project introduced the students to practical
problems. GPS (Global Positioning System) data and
digital images were grabbed on urban streets then
processed and measured to extract topographic information
about distinct objects which were represented in a digital
map. Besides that, the results will help the analysis of real
application data to be produced in the months to come by a
platform that is being constructed.
Reasons for surveying the streets
Most people live in urban areas. Along the streets facility
companies lay their networks say water and sewer, electric
power, telecommunication, and many others. Poles and
trees are quite common in typical urban scenes. They do
help but at some extent they disturb people when walking
on the sidewalks. Pedestrians and drivers (these
representing a large collection of different vehicles) need a
language to communicate to each other in favor of traffic
security, which is expressed in signs and warnings, both
horizontal and vertical. Not only architects and
urbanologists argue for a comfortable urban environment
where humans can live with dignity and happiness. We
could continue and make a long list of nice words to justify
the need for the street and road mapping. Briefly, from a
technical point of view, an image database and digital maps
will help the urban administrators to reach the standards of
a better quality of life. Particularly, mobile mapping
systems (MMS) seem to play an important role in
collecting street and road data for mapping and GIS