International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B6. Istanbul 2004
3. SURVEYS MADE IN BRAZIL USING LIDAR
TECHNOLOGY
The first surveys, using LIDAR technology in Brazil, were
performed in strips of ducts of Petroleo Brasileiro S/A
Company (PETROBRÄS) spread throughout the country. The
purpose was the mapping through altimetry of this strip, with
the purpose of obtaining a Digital Terrain Model (DTM) for
orthophotos rectification. The survey was performed along the
servitude strip. At this stage, they traveled about 3.000 lineal
km with an average strip of 700m, which is equal to 2.100 sq
km of data of LIDAR.
LIDAR surveys were already performed: for the area of
highway engineering, surveys in strips for electric power
transmission lines and strips of peroleum ducts, in urban areas,
in mining areas, for areas of interest for hydraulic potential and
of hydric resources, in reforestation and native forest for
biomass estimates and vegetation classification.
Table | displays the amounts obtained by two companies,
showing that 8.600 sq km were imaged in several places and for
several purposes.
AREA
TYPE OF SURVEY SURVEYED |(%)
(SQ. Km)
Strip Survey: (transmission lines, 3225 37,5
servitude strips of ducts)
Altimetry deviation (DTM for
ortho-photo rectification and to | 2150 25,0
produce contour lines)
Hydric Resources 1800 21,0
Highway Engineering 975 11,23
Urban and rural mapping 400 4,7
Reforestation 50 0,57
TOTAL 8600 100
Table 1: mapped area using Laser Scanner sensor in Brazil
The mapping of hydric resources looked for inventories of
hydroelectric power plants and for the determination of
inundation quota. In the application for reforestations and
native forests, it was used to aid in the biomass estimates, as
well as in the classification of the vegetation (using altitude in
relation to terrestrial surface). In highway engineering, mapping
was performed in preliminary studies of the final project of
highways. Studies are in the process of seeking the use of the
technology in the final phase of highway projects. Urban and
rural maps have been generated, in some cases, utilizing only
by-products of the Laser Scanner sensor, in other cases, they
are the result of fusing Laser Scanner data and products of
digital photographys, as the orthophotos.
4. PRODUCTS DEVELOPED BY COMPANIES USING
INFORMATION DERIVING FROM THE LASER
SCANNER SENSOR
a) Starting from cloud points of the Laser Scanner, countour
lines are created, Hypsometrical Maps, Digital Terrain Models
and Digital Surface Model, compositions of hypsometry colors
and intensity image.
b) Development of applications (during the last two years) for
the owners of LIDAR equipments in the country: for biomass
estimates in reforestation areas; 3D mapping of transmission
lines; programs, exclusively, to work with the technology, as in
the case of a software to deal with information resulting from
»
the LIDAR system seeking the automatic search of falling in
bodies of water.
c) Fusion of Laser Scanner data and others: Some customers
only need the altimetry of a region, for this purpose, the Laser
Scanner is the final product (as the example of Mining
Companies and of engineering projects). The by-products are
demands or customer's needs. If the purpose is to obtain
orthophotos, planialtimetry, etc., the Laser Scanner is a tool that
complements the process, acting in one of the phases (DTM
aquisition). There are already areas in the country, where maps
were produced just by using the products of the Laser Scanner
sensor, without the need of any other by-product (they used
elevation contours derived from laser points and images
resulting from composition of hypsometry and LIDAR intensity
image).
5. RESEARCH IN TEACHING INSTITUTIONS
From the beginning of LIDAR technology in the country,
several research projects are being developed by companies
which have the technology as well as by researchers at
universities. In this manner, the publications begin to appear in
national and international levels of the results reached by these
researchers.
Before the existence of LIDAR technology in the country, there
were already researchers in accord with German universities,
developing works involving Laser Scanner products, which
brought the technique to the country. Since then, researchers
have been developing projects and products, using the
technology, in the country. The first researches, at university
level, were accomplished taking as examples, for their area of
study, urban environments of European cities. They mainly
involved classification of spectral and space images of the Laser
Scanner sensor, detection and identification of constructions and
vegetation.
Nowadays there are several dissertations and theses in progress,
in the country, having as study subject, LIDAR, its products and
applications. And several already finished. Schäfer (2004),
studied of application of LIDAR and orthophotos integration for
use in highway enginnering projects.
One research line is related to the handling of by-products of
LIDAR, as filtering, classification and creation of terrain
models. Subjects as the operational safety of the Laser Scanner
sensor was also a topic of study.
A doctorate thesis is in progress at the Federal university of
Santa Catarina (UFSC). It involves the comparison of results
obtained with the LIDAR system, as related to other types of
available products, to see whether the results are compatible
with the existing cartographic standards in the country.
Another line of research seeks the use of LIDAR by-products
for a great variety of applications. Among the utilizations in
study, we may cite highway projects (figure | and 2) (Schäfer,
2004), the study of relief in areas of hydroelectric plants,
characterization and the monitoring of natural resources
(Groszewicz, 2003), drainage problems, distribution of energy
(Müller, 2002), transmission lines (Baungarten, 2003) and
studies in urban areas (Calmon, 2003; Groszewicz, 2003). There
are already finished researches, including master degree
dissertations, in this line of study.
