HORSEPOWER
Interactions between China, Mongolia and the steppe 2000-0 BCE
An Archaeologist’s Toolbox
By: Limin Huan, Bayarkhuu Noost, Alexander Gorelik
Reviewed by: Ursula Brosseder
You may be interested in knowing what gadgets we are using in our Horsepower fieldwork. As the LEIZA team is preparing for the new excavation season in Mongolia, here are some “bells and whistles” which will appear in our luggage.
Handheld GPS
This is the basic tool for positioning ourselves and the archaeological features during the fieldwork. It receives satellite signal in order to locate itself geographically. A handheld GPS is as small and easy-to-use as a smartphone. However, its accuracy can be distorted for various reasons. Therefore, for high-accuracy location recording (such as < 1m), a DGPS is required.
Figure: handheld GPS and compass
DGPS (Differential Code-Phase GPS)
A DGPS is much bigger and more costly than a handheld GPS, but it can provide much higher accuracy (cm or even mm level) for archaeologists. It consists of a base station (reference receiver) and a handheld receiver (rover receiver). The base station calculates the errors and transmits the real-time corrections to the rover receiver.
Figure: The GPS rover which is connected to the base and the tablet computer. It is used to record the accurate position
Figure: LEIZA Horsepower team are receiving the GPS training
Drone
Utilizing drone photography is becoming more and more commonplace in archaeological surveys, with the new generation of drones being capable of taking high resolution photos and videos at a relatively low cost. Besides recording the landscape and fieldwork scenes, drone photos can also be used to create 3D models for the landform or single features through photogrammetry.
Figure: Drone used in the fieldwork
Figure: photos of previous fieldwork undertaken by Ursula Brosseder and team, taken by a drone, 2023 summer
Computer-based photogrammetry
Photogrammetry is a technology that transforms multiple 2D photos from different angles into a 3D model—with both shape and surface texture. Nowadays, it is so easy to use that even a smartphone can generate quite amazing 3D results. In archaeology, photogrammetry can be used to record and analyze objects of different sizes, from a single artefact to an entire landscape. For archaeological surface surveys, photos taken by a drone or a camera are imported into a photogrammetry software. In this way, a digital surface model (DSM) can be generated to record archaeological features visible on the modern surface. The software can also recognise “base points” and use them to position the scene geographically using GPS coordinates.
Photogrammetry by: Anja Cramer
Figure: Photos are matched in Agisoft Metashape to create the 3D model for a satellite deposition containing a horse head
Figure: Different layers of the satellite 3D model
Left to right, top to bottom: A: B: C: D
Last but not least…
Even a small fieldwork project involves lots of small but important details and lots of preparation, from the scientific data recording to the welfare of the participants.
Figure: first aid and kneeling pads prepared for the fieldwork