Hadleyville Cemetery Part 2

·         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.