King George Island is one of the best surveyed areas in Antarctica. Nevertheless good ground control to georeference satellite imagery is still lacking for some areas. Satellite images are an invaluable means to map areas, to derive thematic information (e.g. vegetation maps), and to monitor environmental changes. To use these data in scientific and environmental applications the images need to be referenced to real world locations. This can be achieved by relating measured real world coordinates to features visible in the images. As part of the SCAR King George Island GIS project and as a contribution to the work of the GLIMS Regional Center 18, Antarctic Peninsula, we strive to set up a ground control database that is accessible on the internet for use by all countries and for multidisciplinary applications. The database will help researchers working in the area to establish precise geographic or UTM coordinates to assist with georectification of satellite imagery.

Especially if you work in this summer's 2004/05 season in remote locations on King George Island you can help a lot if you are able to provide ground control information for that location which is inaccessible to others.

We intend to give you some guidance on where on King George Island Ground control to georeference satellite images is still missing and where appropriate points might be recorded. It also provides the means to document the location of your measurements.

We do not aim at measuring points for geodetic or photogrammetric control! A geodetic survey demands more accurate measurements than generally required for satellite imagery control.

The accuracy needed to reference a Landsat TM/ETM image is +/- 10m, for a SPOT or ASTER image +/-5m, for high resolution imagery (IKONOS, Quickbird) it should be within +/- 1m. These accuracies can readily be achieved even with small, handheld GPS if you record an average over some 15min to 30min time. If you have the possibilities to take ground control at one of the specified locations you are encouraged to use this paper to document the location of your recordings. You also have to document the measurement itself (e.g. equipment, method, accuracy). Most institutions have their own specifications on how to do this. If you are not provided with such specifications you might use the guidelines below that indicate the minimum of documentation required.

We have a prepared a pdf-document that you can print out and use in the field. we encourage you to have a look at it if you are going to any place on King George Island and you have some GPS equipment with you (even small handheld devices).

Click here to download the pdf document (1.5Mb).

We provide overview maps and large scale imagettes of locations on King George Island where ground control is still needed. In some imagettes you find suggestions on where “good” points (i.e. identifiable in satellite imagery) may be recorded. These suggestions are marked as green circles. Feel free to use any other location if better suited. Unfortunately we cannot assess whether one of the suggested points is accessible or not. If you know that one of the locations is too dangerous to access please drop us a note, we’ll skip it from this document.

If you have any ground control points for the respective areas or any other area of King George Island notification to one of the authors of this paper would be greatly acknowledged. If you have any further questions don’t hesitate to contact us.