Sedef Island. Photo from Google Earth.
Back in August 2002 my friend Teri Varnalı and I went to Sedef Island in the Sea of Marmara off the south coast of Istanbul. We had a nice lunch in the restaurant (there is only one) and then collected snails along the path that goes from the pier to the beach.
There we found Zonites algirus, a species that had not been seen in the Istanbul area since 1863. That discovery was the subject of a paper I subsequently published1.
Most of the specimens of Z. algirus and the other species we collected on the island were from a location I designated as my station A15. I also measured the coordinates with my handheld GPS receiver.
Earlier today, I got curious and plugged the coordinates of A15 into Google Earth. I was taken to this spot.
Photo from Google Earth.
According to my notebook, however, A15 was facing "a semi-circular opening" along the road. You can see the semi-circular opening, the actual location of my station, slightly to the northeast of the spot marked A15 in the picture. The straight distance between the actual location and the marked spot is almost exactly 25 m.
I guess for most practical survey purposes the measured coordinates are good enough provided that there is also a clear description of the station. But stations for which only descriptions are available are usually difficult to relocate.
1Örstan A. 2003. The rediscovery of Zonites algirus in İstanbul, Turkey (Gastropoda: Pulmonata: Zonitidae). Zoology in the Middle East, 29:75-78.