·
Introduction
o
Provide background to the problem at hand. What
are some of the problems and challenges facing Hadleyville Cemetery?
§
The town of Pleasant Valley would like a detailed, accurate
map of the Hadleyville Cemetery; however, all maps and original records have
been lost. The cemetery also has monuments dating as far back as 1865, many of
which are likely made of limestone or marble. These materials tend to degrade
over time and many of the engravings will be difficult or impossible to read.
Burial plots with no remaining monument marking them will also add to the
challenge of creating a complete collection of attributes for each plot.
o
Why is building a GIS
of this project better than a simple map and/or spreadsheet?
§
A GIS will attach the collected attribute data
to a specific geographical location within the cemetery; this method will make
utilization of the data much more user friendly and preserve the data more
extensively. Factors such as weather and vandalism could result in loss or
relocation of a monument. A GIS will have the data attached to the location of
the plot, making it much easier to replace the monument and to verify occupancy
of a particular plot for future additions. In the past cemeteries have used
identification numbers for plots and visitors were given the ID number
corresponding to their loved one, as well as a general area within the cemetery
the plot could be located. This method can make locating a plot somewhat
difficult and time consuming, particularly for nonexistent or illegible
monuments and/or those who have never visited the cemetery. If made accessible to the public, a GIS would
also make it easier for visitors to locate their loved ones. Users could access
a high resolution image of the cemetery and locate the plot with data for their
loved one, the predominance of smart phones also adds to the convenience of
this method.
o
What equipment are you going to use to gather
the data needed to construct the GIS; i.e. what is the overall approach?
§
In order to obtain base map imagery a UAS was
programmed to execute a series of flights around the cemetery. The attribute
data will be collected using a field notebook and photography; in a field notebook
a basic layout map will be drawn with each plot numbered and attribute data corresponding
to each plot recorded. As the attribute data is collected each monument will
also be photographed using a cell phone or digital camera. In order to obtain
very precise locations of each plot, their locations will be recorded using a
survey grade GPS.
o
What are the overall objectives of the method
being employed to gather the data?
§
A detailed image of the cemetery to use for the
base map would make it much easier for one to orient themselves and
successfully locate a specific plot while in the cemetery itself or from
another location, using a UAS with high resolution photography capabilities
will make this possible. The basic layout with a numbering system used to
designate attribute data to a plot along with photographs will help ensure
accuracy of the attribute data collected. The photographs could also be
potentially used as a pop-up image when the corresponding plot is clicked on by
a user viewing the map, if a web map is created.
·
Methods
o
What combination of geospatial tools did the
class use in order to conduct the survey? Why?
§
A UAS from the Phantom series was used for the
aerial imagery. According to www.dji.com , the
entire Phantom series contains a gimbal with 3-axis stabilization capabilities
and are all created for high-level aerial photography. The class used notebooks
to record data and cellular phones to photograph the same data that was
recorded manually, this will help to ensure accuracy. The photographs will be
useful in assessing any un-noted or un-clear data. The use of a survey grade
GPS receiver was attempted, however a complete list of points would have been
extremely time consuming and a signal was not found when under trees. This GPS
receiver was selected over a mapping grade receiver because the mapping grade
GPS is generally accurate to within a meter, many plots are closer together
than this.
o
What is the accuracy of each piece of equipment
you are intending to use?
§
According to an article posted by Mike Tully at http://www.mapps.org/blogpost/726441/237476/Just-How-Accurate-is-Your-Drone
, a combination of factors contribute to the overall positional accuracy of the
orthophoto produced. Some of these include; the camera`s potential, the
stability of the flight, the quality of the GPS data, and the number and
quality of ground control points. Based on these factors alone, the Phantom
appears capable of producing accurate imagery for the project: The UAS Phantom
series boasts high quality and well stabilized cameras, the flights were made
on a day with little wind and appeared to be stable, the cemetery itself is
large enough that GPS data should be sufficient for locating it, the six ground
control points used in the 1.5-acre cemetery were sufficient and well-marked
with bright colors. Had the survey grade GPS been successfully used, they are
accurate up to a centimeter. This accuracy would avoid overlap in points that
could have occurred with a mapping grade GPS.
o
How was the data recorded? List the different
methods and state why a pure digital approach is not always best. What media
types are being used for data collection? Formats?
§
The aerial imagery was recorded digitally using
a camera, this was necessary for a detailed base map. The attribute data was
recorded manually in a notebook, but also documented using the camera of a cell
phone. Data empirically collected in-situ tends to be the most accurate and a
hardcopy of attributes helps to ensure the data is not lost.
o
How will you transfer the data you gather into a
GIS?
§
Once the base map has been created and properly
projected, location points will be added for each plot on the map. An excel table
of all attribute data as well as coordinate information designated by the
points will then be created, the table will be converted into a csv files, and
then imported into a GIS by linking it to the coordinate points.
o
What
equipment failures occurred, if any? What was done to remedy the situation?
§
There was only one survey grade GPS unit
available for use and data collection was taking a very long time. The unit
also did not maintain service when under trees. Due to these difficulties the
collected coordinates were discarded and the use of the equipment eliminated
from the project. The clarity of the aerial imagery combined with the detailed
data collected will make completion of this project possible without GPS
coordinates for each plot.
o
What might have been done to facilitate data
collection in terms of equipment and refining the method?
§
The collection of GPS data could have been
successful if at least two were available and they had stronger receivers. There
were also some large gaps in between graves as well as some monuments piled along
the edges of the cemetery, indicating the presence of unmarked plots. GPR equipment
could have most likely shed some light on the locations of unmarked, occupied
plots.
·
Conclusion
o
How did the methods transfer to the overall objectives
of the project?
§
The use of a UAS to take aerial imagery will produce a detailed
and accurate base map. The collection of as many observable attributes as
possible as well as digital photographs of each site where data was observed
will enhance the detail of the finished product.
o
How did the mixed formats of data collection
relate to the accuracy and expediency of the survey?
§
Each method of data collection contributed to
successfully collecting all data necessary to meet the goal of this project, to
create a detailed and accurate map of the Hadleyville Cemetery. If only the UAS
was used, it would have taken a very long time for someone to manually drive it
to each plot site and take an up close photograph, on the other hand no selfie
stick would have been long enough to obtain the quality of aerial imagery we
were able to obtain using the UAS for the base map. Photographs taken during empirical
data collection created a backup for any questionable data collected.
o
Describe the overall success of the survey,
and speculate on the outcome of the data.
§
Before setting out to gather data, the class
as a whole did not communicate methods of collection or assign groups to areas.
However, after separating and realizing this small groups did communicate and
then other small groups communicated further with other groups. This survey
method may result in some overlap in data collection and perhaps a few gaps,
but it is likely that very close to all plots were observed and accounted for. If
there is any overlap, that data would either match or be looked at more closely,
both resulting in better accuracy.
