Applying Microsoft Excel and Computational Scripts to Calculate and Digitize Artifacts Measured via Trilateration
Abstract
This study focuses on the application of software and informatics to the growing practice of underwater archaeology. One common challenge present to underwater archaeologists is the mapping of seafloor artifacts, as the application of GPS technology while underwater is an inefficient procedure. Traditionally, submerged artifacts are measured by taking two separate measurements to a baseline with an origin of known coordinates and degree bearing from the true north. Then, archaeologists can effortlessly map the location of these artifacts by hand using a geometric compass. However, this presents a great deal of error when transcribing a hand map to a digital GIS software, common for creating digital maps and performing various spatial data analyses. This study seeks to bypass the error involved in hand-mapping by devising coding scripts that use the trigonometric law of cosines and several conditional operations to calculate the exact geographic coordinates of an artifact entirely digitally. A Microsoft Excel spreadsheet formula will allow for novices in GIS to easily read and assess the measured artifacts' coordinates, whereas a Python 2.7 script presents informatics and GIS specialists with a tool to efficiently project these coordinates as points onto a data frame within ArcMap 10.7.
Applying Microsoft Excel and Computational Scripts to Calculate and Digitize Artifacts Measured via Trilateration
This study focuses on the application of software and informatics to the growing practice of underwater archaeology. One common challenge present to underwater archaeologists is the mapping of seafloor artifacts, as the application of GPS technology while underwater is an inefficient procedure. Traditionally, submerged artifacts are measured by taking two separate measurements to a baseline with an origin of known coordinates and degree bearing from the true north. Then, archaeologists can effortlessly map the location of these artifacts by hand using a geometric compass. However, this presents a great deal of error when transcribing a hand map to a digital GIS software, common for creating digital maps and performing various spatial data analyses. This study seeks to bypass the error involved in hand-mapping by devising coding scripts that use the trigonometric law of cosines and several conditional operations to calculate the exact geographic coordinates of an artifact entirely digitally. A Microsoft Excel spreadsheet formula will allow for novices in GIS to easily read and assess the measured artifacts' coordinates, whereas a Python 2.7 script presents informatics and GIS specialists with a tool to efficiently project these coordinates as points onto a data frame within ArcMap 10.7.