Garth, who was leading the small investigation team, could've seen inside a small tent that was just erected with a few other officials as they looked over a crude map of the area. Due to how impossible it was to secure a win against the undead, there was no map that showed the entire area in detail.
The one they had was secured through the use of the Gryphon riders who aren't excellent map makers but at the moment, just knowing how far away each undead city was from each other was enough. They had been here for two days straight and since they missed the capture of the ghoul cities.
They had to prepare for when the soldiers that were just loitering in the ruins of the city eventually move. They needed to know where and from where they would attack to allow them to plan a spot where they could watch without being involved.