My favorite piece

1. Utilizing LiDAR on the Dos Hombres to Gran Cacao Transect
Amber V. Wadlington
Anthropology 350 Method and Theory in Archaeology
Professor Marisol Cortes-Rincon
December 7, 2012

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LiDAR or Light Detection And Ranging is a modern tool that can generate highly
accurate terrain models that are used in Geographical Information Systems (GIS). LiDAR data
and acquisition are the future of aerial survey and have been used with great success at many
archaeological sites around the world.Recently at the Mesoamerican archaeological sites of
Caracol, Cayo, Belize and Angamuco, Mexico, great success has been achieved using this
geospatial innovation. Dr. Diane and Arlen Chase, archaeologists at the University of Central
Florida in Orlando utilized LiDAR in their research at their sites in Belize and Mexico.
Theyclaimed that,“LiDAR-derived data act as a permanent horizontaland vertical document of
everything on the landscape including archaeological remains, vegetation, topography at the time
the data are collected, thus also recording the status of site preservation and looting,
deforestation, and modern construction at a single point in time”(Arlen F. Chase et al. 2011).
Using LiDAR systems to map a 12.4 km transect at the Dos Hombres to Gran Cacao
Archaeology Projectwill provide extremely useful terrain models and GIS data and it will also
provide students and faculty training with hardware function, software function and data
manipulation. By providing students and faculty a chance to utilize LiDAR we will be taking a
step into the future of survey technology.This project will provide highly accurate detailed dataof
the site andit will do so in an extremely efficient manner.
The Dos Hombres to Gran Cacao Archaeology Project is headed by archaeologist Dr.
Marisol Cortes-Rincon of Humboldt State University. It is located in the Northwest region of
Belize in the Orange Walk District see figure 1. The Dos Hombres to Gran Cacao Archaeology
Project is under the Programme for Belize Archaeology Project (PfBAP) in the Programme for
Belize Conservation and Management Area.Dos Hombres to Gran Cacao Archaeological Site is
currently working to add to the comprehension of how ancient polities were organized in the

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central Maya lowlands of Belize.The study focuses on the investigation of economic and
political organization between the Mayan sitesDos Hombres and Gran Cacao. Settlement
mapping and analysis of the area between these two sites is integral to this investigation. Gran
Cacao is located 12 km northeast from Dos Hombres. There are future plans for investigation of
an eight mile transect between Great Savannah and Dos Hombres.As well as a four km transect
between Great Savannah and Gran Cacao. The site is densely forested and as such survey is a
very slow process. Arial and Satellite imaging of the surface of this transect is almost completely
useless because the surface of the ground is all but visible. There is however one very useful
exception and that is LiDAR(Dos Hombres to Gran Cacao Archaeology Project2011 Interim
Field Report 2011).
Figure 1 Dos Hombres to Gran Cacao transect
Archaeologists have hailed LiDAR as a catalyst for change in the way we conduct
Archaeology. The resolution of surface features that can be detected is unparalleled.Advanced
post processing of the data has the ability to break through canopy cover and reveal previously
hidden archaeological features(Devereux, Amable, P. Crow, et al. 2005). The technology that
LiDAR uses is very complex however the way that it functions is a fairly simple concept.The

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LiDAR hardware is mounted to an airplane or helicopter.It includes a powerful laser that has
both a transceiver and a receiver(Parcak 2009). Thousands of small bursts of laser energy are
aimed at the ground and are emitted from the transceiver on an airplane or a helicopter(Young
2011). Each laser point of energy is then reflected back and absorbed by the receiver(Young
2011).The laser sensors pulse laser beams that penetrate tree canopies and other
obstructions(Fernandez Diaz 2011).Each pulse of laser spreads out in a cone shape as it reaches
further from its source; when it reaches the ground it creates a circular area on the ground(Hesse
2009). The circular area is called the “footprint” and is anywhere from 10 to 15 meters in
diameter(Hesse 2009). If the “footprint” reaches a flat area all the light is reflected back all at the
same time, however if it hits a laser permeable facade such as a forest canopy some of the light
travels further down and is reflected at a later moment(Devereux, Amable, P. Crow, et al. 2005).
A powerful laser pulse and a canopy with gaps in it will produce the highest amount of data
points that reach the ground(Fernandez Diaz 2011). The first part of the distribution which
comes from the top of the tree canopy is called the “first pulse” and when it reaches the ground it
is called the “last pulse” See figure 3. Swath’s that overlap increase the amount of lasers that
reach the ground(Devereux, Amable, P. Crow, et al. 2005).They are then recorded by a laser
scanner. The time is recorded between when the laser was emitted and received, that number is
broken in half and multiplied by the speed of light(Crutchley and S. Crow 2010).The inertial
measurement unite or IMU measures the altitude of the sensor on its platform it is called the roll,
pitch, and heading of the platform(Crutchley and S. Crow 2010).The mounted GPS reports the
location of the platform of the sensor, or where the aircraft is carryinga LiDAR system(Hesse
2009). The points that are recorded by the system relate the data to actual points on the ground in
conjunction with a GNSS base unit positioned on your project site(Young 2011). Relevant

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longitude, latitude, and elevation (x,y,z) position for every data point are collected and
transmitted to the base unitand are recorded(Young 2011).Measurements can be as precise as
3cm to the actual height(Crutchley and S. Crow 2010). The GPS data points or “point cloud” is
then used to create a computerized 2D or 3D Digital Elevation Model (DEM) of the
ground(Young 2011). Even before the survey is complete, the data collected can be uploaded to
computers where digital elevation models, can be accessed to start the analysis process of the
survey(Aerial Surveying INC. 2012).Software can then convert the data into a variety of formats
including LAS, ASCII, ESRI and CAD(Aerial Surveying INC. 2012). The most common use of
the data is with 3D CAD(Young 2011).The best way to understand how LiDAR will work is to
investigate its use on archaeological sites in Cayo and Carcol in Belize andAngumunco, Mexico.
Figure 2 How LiDAR works

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Figure 3 How LiDAR penetrates the canopy
Dr. Arlen and Diane Chase Maya archaeologists at the University of Central Florida have
been conducting archaeological research and survey in Belize for the last 25 years. In specific
they have been conducting survey at Caracol for the last 25 years(Arlen F. Chase et al. 2012).
Caracol is described as the largest site in the Southern Mayan lowlands and the site is
approximately 200 see figure 3(Arlen F. Chase et al. 2011). The Chases attained a grant
from NASA in 2009 in order to conduct a LiDAR survey that would reveal the surface of their
200 site below the dense rainforest canopy(Arlen F. Chase et al. 2011). This covered nearly
the entire Vaca Plateau. The National Center for Airborne LiDAR mapping a part of the National
Science Foundation employed graduate students and professors from the University of Houston
and the University of Berkley (Fernandez Diaz 2011).The survey successfully displayed
previously mapped and unmapped features of the entire 200 area it included undiscovered
structural groups, agricultural groups and causeways(Arlen F. Chase et al. 2011). Because of this
they were able to identify the entire Vacaplateau as single city(Arlen F. Chase et al. 2012). The

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LiDAR survey was done with an OPTEC Airborne Laser Terrain Mapper(Arlen F. Chase et al.
2011). The survey was done May 26th
thru the 30th
, because the end of the dry season in Belize
provides the maximum amount of “leaf off” conditions which provides the most ground
visibility(Arlen F. Chase et al. 2011). There was 23 hours of flight time with over 9 hours of
laser use(Arlen F. Chase et al. 2011).They flew a dual engine Cessna at an altitude of800
meters(Arlen F. Chase et al. 2012). They flew 62 north-south flight lines and 60 west-east flight
lines spaced at 260 meters(Arlen F. Chase et al. 2012).They overlapped the coverage by 200
%(Arlen F. Chase et al. 2012). The airplane traveled at a ground speed of 80 meters per second
and the pulse rate of the laser was 100 khz. 2.38 billion Lasers were fired which provided 4.28
billion measurements and 1.35 laser shots per reached the ground(Arlen F. Chase et al.
2011).These features were terraces and as much as 15% more plaza surfaces were revealed
through LiDAR than through ground survey(Arlen F. Chase et al. 2011). Features that were
previously missed during ground survey weredue to the growth of the rainforest, LiDAR has
successfully broken through these barriers(Arlen F. Chase et al. 2011).
Figure 4 Caracol, Belize Site

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I took the time to weight some possible optionson how I was going to conduct a LiDAR
survey of the Dos Hombres to Gran Cacao Archaeology site. Two basic options include
purchasing the LiDAR equipment or planning out a survey of our own and hiring a professional
to conduct the survey that would provide us the option to participate in data collection. I
researched and attempted to contact many different companies that provided LiDAR services and
found it quite hard to get a hold of anyone. I emailed and called several companies multiple
times and was never able to get a hold of them. This was quite frustrating as I would have
preferred to have a variety of options to choose from. I contacted a few companies that did not
work outside of the USA. I also searched for companies within Belize itself and was unable to
find any at all. I found companies all over the world that used LiDAR; however there are many
different uses for LiDAR and it is utilized in a variety of different ways. Finding a company that
conducted airborne LiDAR in Belize was a task however I was successful. I contacted LiDAR
dealers that sold systems from companies likeLeica, Optech and Riegl(Lemmens 2009). Through
contact with multiple sales representatives for companies Leica, Optech and Riegl I have found
that purchasing a quality turnkey airborne LiDAR system ranges on average from 800,000 to 1
million dollars see figure 5.They include all hardware necessary to conduct the survey. They
usually include software for post-processing. However it does not include a computer to run the
software or utilize the software. It also does not come with a Survey grade dual-frequency base
station, or equivalent accuracy reference station source or GPS station(Lemmens 2009). In order
to use the equipment it must also be insured for the full cost the initial purchase(LiDAR Services
2012). There is an exemption for paying duty on items brought in for scientific research however
the sheer value of the merchandise may complicate the situation(Belize 2000). We would need to

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procure a pilot who was skilled in conducting a LiDAR and aircraft to conduct the survey. The
process of attempting to plan this venture would be extensive and cost preventative.
Figure 5 Turnkey LiDAR Equipment
I found a Company called Aerial Surveying Incorporated that is headed by Thomas
Pattison. The company is based out of Hawaii. They have done LiDAR work in Belize in the
past. This company provides the hardware, aircraft and software. According to Thomas Pattison
and his web site aerialsurveyinginc.comthey will provide a survey grade dual-frequency base
station, reference station sourceor a GPS station.High grade digital photos will also be provided.
Students and faculty will be able to work and observe data collection at the base station and
observe hardware when mounted on the plane. A high end computer must be obtained for post
processing. Software must also be purchased in order to fully utilize the 3D Digital Elevation
Models.Aerial Surveying, Inc. will fly aerial surveying missions anywhere in the World to
produce topographic maps that are construction grade, create 3D Digital Elevation Models, and
do Flood Plane Mapping Analysis. Their “in-house” land surveying department does all of their
ground calibration to verify the accuracy of their aerial surveying data. Land surveying services
on each project include, on the ground survey of dense canopy areas, locating property corners
andconnecting LiDAR data points to those corners. Ground calibrations are done to verify aerial

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LiDAR data and are included. The collected aerial LiDAR data is used to produce 3D DEMs,
topographical maps showing land contours, plus information for flood plain analysis and flood
drainage mapping. They use an AutoCAD or a .dxf format which they will upload to their FTP
server that can be accessed easily. An “as-built” survey can be added to your base map. Aerial
photographs are taken during the flight missions for every project and are included at no extra
charge.I decided that purchasing LiDAR equipment and planning a survey would be far too
expensive. I chose to hire professional LiDAR surveyor Thomas Pattison from Aerial Surveying
Incorporated(Aerial Surveying INC. 2012).
Planning a survey and creating a budget for a survey requires a great deal of planning. I
have attempted to make a rough plan and estimate that could be used as an outline for the
project. Two professors and four students will travel to Belize and meet up with his crew in late
May or early June of 2014. This time is important because it is at the time when the most leaves
will be off the trees providing the greatest ground visibility(Arlen F. Chase et al. 2011).It should
also align with the end of the spring term and the beginning of the field school session. Two
faculty members and four students will travel to Belize and meet up with Thomas Pattison and
his crew. This survey should last no more than a week and as little as one day. Thomas Pattison
provided a rough estimate for conducting this LiDAR project of 38,000 dollars.If the survey at
Caracol only took four days to complete our project should last no more than a week but could
take as little as one day(Arlen F. Chase et al. 2011). I estimated the cost for transportation,
lodging, incidental expenses, educational resources, software and a computer at 20,000 dollars.
This estimate is very rough and would require more research to come up with a solidbudget.
With my rough budget and Thomas Pattisons’ estimate we would need to figure in a 15% cut for

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The Programme for Belize Archaeology and a 22% cut for Humboldt State University we would
need a total of 107,000 dollars.
As you can see airborne LiDAR will be an efficient effective and transformative way to
provide students and faculty experience with LiDAR and an enormous amount of data for future
surveying and excavation on the Dos Hombres to Gran Cacao Archaeology Project. This project
will provide students and faculty a chance to utilize LiDAR and will also provide highly accurate
detailed data of the site.This project aims to give students a chance to be on the cutting edge of
technology in archaeological mappingLiDAR data and acquisition are the future of aerial survey
and have been used with great success at many archaeological sites around the world. I would
like to make the Dos Hombres to Gran CacaoArchaeological project one of those success stories.
I explained how LiDAR works, and how it was successfully utilized by other professional
archaeologists in Belize. I also provided an outline of theplanned LiDAR project and provided a
rough budget for it.Using LiDAR systems to map a 12.4 km transect at theDos Hombres to Gran
Cacao Archaeology Project will provide extremely useful terrain models and GIS data and it
will also provide students and faculty training with hardware function, software function and
data manipulation. This will help the archaeology project answer questions about how ancient
polities were organized in the central Maya lowlands of Belize. It will also add to the
investigation of economic and political organization between the Mayan sites Dos Hombres and
Gran Cacao. It will also provide enhanced settlement mapping and theanalysis of the area
between these two sites.By providing students and faculty a chance to utilize LiDAR we would
be taking a step into the future of survey technology which will not only provide a highly
accurate detailed data of their site but it will do so in an extremely efficient manner.

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http://www.aerialsurveyinginc.com/, accessed October 25, 2012.
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