I myself don't Map/Pendulum dowse. I've tried it, seen it done, own a couple pendulums, but I dont feel or observe any reaction when I try. What I do know is L-rod dowsing, and figured most of it out. Therefore it becomes Science, not fiction. Most people with the same knowledge can duplicate all experiments with the same results. To aid in my l-rod dowsing ability I use what works best, and know when to do so. I found that certain lengths and rod materials react better than others, and I know that my l-rod dowsing power is not constant. Map dowsing is a totally different type of dowsing. To bizarre to be called science. But I would assume all the basics still apply. Their could be a specific length pendulum that works better than others, or the material it's made of doesn't work for you. It might need to have a chamber for the element, or it might need to be tipped with a neutral crystal. Their might even be better times to Map Dowse than others. Anything and everything is posible..