The end product of site plan maps is on the printed page. To get there, archaeologists map site features to scale in the field using graph paper and rulers.
Back at the office, the drawings are digitized by either taping the graph paper to a digitizer board or scanning the map into a digital format. The feature on the map is then digitized and added to the overall site map.
PAR archaeologists are breaking ground with a new method of site mapping which replaces the standardized methods established almost 60 years ago. First tested on a small prehistoric camp near the Grossmann site in Shiloh, Illinois, this giant leap in cartography was officially taken during PAR's mitigation of site 11Ms172 in Granite City, Illinois where the graph paper and rulers were put away for good. In their place, a relative newcomer to consumer and professional toolkits was utilized: affordable aerial photography.
The new method sends a drone into the air, which snaps a digital image of the feature along with some datum points, which will be used to orient the feature on the site map.
The features are digitized from the aerial photograph using Mapwerk for the Mac. Mapwerk is an application developed by PAR's Jason Rein for use in assisting with general mapping duties in the field and office. Among a wide array of features, it's functionality includes the native ability to import digital imagery, set its scale, and digitize objects within the image. This feature set makes it ideal for mapping an archaeological site with a drone.
Site datum points are set out in the field and mapped in using a total station. These points are used as reference markers and can be later be used to convert the grid to real-world coordinates. The total station operator may also map in nearby roads, buildings, and field edges to visually assist placing the site map on a real-world map.
Once established, Mapwerk will import and draw all points and lines on the map. The drone imagery is then dropped in and its scale is set using the reference nails captured in the image. The image is then rotated and positioned by aligning to the datum points on the map. Once the image is set, the feature can be digitized. The process completely removes the "middle man" of taking measurements in the field and drawing the results on graph paper. The result is as accurate as the photograph that captured it.
Mapwerk can be utilized in the field to assist with traditionally-drawn feature plan maps. Pull out the rulers but leave the graph paper behind. With Mapwerk's "Baseline Mapping" functionality, site features can be digitized in the field using the established datum points and the relative measurements taken by the mapper.