Hey Nich37ways, You are correct in your observation. We use the Pioneer from our friends at Active Media, Mobile Robotics as our platform for data collection. While various SLAM techniques have been around quite a while, the methodology we use gives us very high accuracy data. As you point out, odometry isn't very reliable, especially in variable terrain environments, so our approach uses a number of integrated sensors to create floorplans. Combined with posterior pose algorithms during post processing, we get great results.