The coordinates are located on the small island East of Ogre City, between the spear wall and the dead tree. However, to get to that island, you have to walk around the outside of Gu'Tanoth (Ogre City) until you get to the bottom. Start on the Castle Wars side (West side of Gu'Tanoth) and go South until you reach the bottom corner. Then start walking East. Not too far from the Southwestern corner, you'll see a dungeon entrance just beyond a some ruins near the slope. Go inside the cave, and you'll instantly appear on the island. No quests are required to get onto the island. Refer to this map to see where the dungeon entrance is -- at the green dot in the bottom left-hand corner. From: http://tip.it/runescape/?page=coordinates_list.htm