All surveying work is done outdoors and their marking requirements include stake marking and marking on all types of outdoor surfaces. Permall® Ink Markers like IM-18 are formulated to be UV resistant, fade resistant, abrasion resistant, and waterproof which includes snow as well as rain. It's permanent in all outdoor situations on most surfaces. Any of our other permanent paint-markers are versatile enough for the marking needs of surveyors as well.