Category Archives: AFF601

Guest Speaker Angeliki Chrysanthi – Geotagging

Georeferencing is used to specify geographing location with code or the place. This can be done through various softwares, automatically, semiautomatially or manually adding metadata to files in question.
Embedded metadata informs about who took the image, where it is, any kind of technical information available such as camera settings(usually stored by the device automatically). Copyright information may be included in some cases. Geotagging may be done automatically for the device if it is GPS enabled. EXIF data is taken automatically from devices, shutter speed, GPS etc. Largely functions to connect a photo to the place, time subjects etc. GPS devices capture timestamps in a GPX format. GPS devices can store either track logs (drawing a path or directions) or capturing specific points according to a time (every 5 secs for example). A devices clock must be synchronised in order for it to work with GPS as it gets you the time of your image. Metadata, including GPS coordinates can also be added manually, and can be done when images are digitised – particarly with GPS coordinates as if you don’t have the camera settings from a manual camera than you will never have it. Digital creators describe the content of the image, either embedding it as part of the digital file or as an external “sidecar” file as part of a referencing system
Examples were given by Hochman, Manovich and Yazdani 2014: ”On hyper-locality: Performances of place in Social Media” which explored the relationship between the physical space and the digital – an interesting topic, particularly when geotagging is relatively accessible to consumers through apps and social media today. Geotagging can be very useful for fields like Archaeology – which the examples in the practical section were related to, or community based projects like the Historic Graves projects discussed. Many have adopted such methods because photos can be attached to where finds have been made. Its also been useful for Archival images including lithographs and paintings – sometimes tracked across 100s of years through digitised images with estimated locations in some cases.
In the practical section we learned how to manually add GPS data to image files, and how to batch add data using external files using Geosetter – shown in the screenshot below. There was a discussion about the different types of coding and programs to use best for different purposes – including several examples. Geobabel assists when there are GPX files, facilitates Geosetter to read files when they are not in the right format. The data files in this case were used to construct a map including tracks, which was a relatively straight forward process one we learned how to use the software. The capabilities to extend the use of such principles can be seen in the development of software like Archdis can convert the data to shape files reducing it all down to points.


Data gathering is massively important, which was explained through examples. Approaches need to be modified and improved on, depending on who the target audience are. What really stood out to me was the search for feedback in the examples. Case studies, questionnaires and interviews were used and while they were useful there were gaps in the information – especially as the participants involved were just behaving as normal with a GPS device in their pockets because they were already used to going about taking photos and weren’t so involved in the GPS logging side of Archaeology. There can be different concentrations of images(hotspots), but certain images may be of more significant points. Results as always require interpretation.

The additional reading provided was very interesting, highlighting the importance of Metadata standards for Geotagging and some of the guidelines around this topic. Schemas are used making the data readable, and usable externally. This reading was produced by EMDaWG (Embedded Data Working Group – Smithsonian Institution) and it largely contains technical information. Data needs to be processed, ensuring the same GPS formatting is used etc., and that the attached data is machine readable and logical.

Overall, this was a very comprehensive introduction to quite a vast topic This type of research needs some planning and foresight, with considerations around the dataset the audience and more.

Bibliography

EMDaWG (Embedded Data Working Group – Smithsonian Institution) “Basic Guidelines for Minimal Descriptive Embedded Metadata in Digital Images” April 2010.

Hochman, Manovich and Yazdani ”On hyper-locality: Performances of place in Social Media” 2014.