The objective, to put in colloquial terms, is to create the “HGTV” effect, it has to “pop.” Leaders should be able to discern the battlespace at first glance the terrain model must be easy on the eyes and intuitive. Techniques shared in this article will strike the balance between time available for construction and the complexity of construction. Preparation, foundation construction, terrain building, and presentation create the framework for this discussion. It is intended to supplement current literature and to share lessons learned, specifically focusing on-site construction process. The intent of this article is to provide some overarching guidelines and lessons learned for terrain model construction. But when the rehearsal site needs to show the entire area of influence combat enablers, and specific micro details, middle management, needs to be involved. Most leaders lack experience in large terrain model construction and pass this task to junior officers or NCOs. To better convey the commander’s intent, units must build an intricately detailed terrain model to provide clear visualization. As a result, rehearsals can suffer, sometimes causing confusion or even embarrassment. These techniques are expedient but do not accurately convey the challenges of terrain. This results in the purchase of large-scale maps or simply arraying plotter pictures of objectives. At the Brigade, Division and Corps levels, site construction is often last in planning priorities. Captains Career Courses and the Command and Staff College have not dedicated curriculum to this subject. The March 1998 CALL Newsletter “Rehearsals” has good information, but could be updated to meet the requirements of the modern battlespace. But both the literature and training on this skill are thin. For a combined arms rehearsal (CAR), a good terrain model is necessary to enhance collaboration and dialogue requisite for good planning and unity of effort. The tools operate on the assumption that for any single cell, water can flow in from many adjacent cells but out through only one cell.Terrain Model construction is an often undervalued step to enhance shared understanding of the mission. There is an assumption that the surface contains sufficient vertical relief that a flow path can be determined.
The hydrologic analysis tools are designed to model the convergence of flow across a natural terrain surface. Again, this is most noticeable on integer data in flat areas. This can increase as much as 5 percent for a 3-arc-second DEM.ĭEMs may also contain noticeable striping artifacts, a result of systematic sampling errors when creating the DEM. It is not uncommon to find 1 percent of the cells in a 30-meter-resolution DEM to be sinks. This can be particularly troublesome in areas of low vertical relief. Another common cause of sinks results from storing the elevation data as an integer number. The number of sinks in a given DEM is normally higher for coarser-resolution DEMs. Learn more about removing or filling sinks.Sinks, being areas of internal drainage, prevent downslope flow routing of water. These are more commonly natural features and are less detrimental to the calculation of flow direction.Įrrors such as these, especially sinks, should be removed before attempting to derive any surface information. Likewise, a spike, or peak, is an area surrounded by cells of lower value.
Some of these may be natural, particularly in glacial or karst areas (Mark 1988), although many sinks are imperfections in the DEM. A sink is an area surrounded by higher elevation values and is also referred to as a depression or pit. Visualization of a raster DEM surface.Įrrors in DEMs are usually classified as either sinks or peaks. Other factors affecting accuracy are data type (integer or floating point) and the actual sampling of the surface when creating the original DEM. The accuracy of this data is determined primarily by the resolution (the distance between sample points). This data is used as input to quantify the characteristics of the land surface.Ī DEM is a raster representation of a continuous surface, usually referencing the surface of the earth. The most common digital data of the shape of the earth's surface is cell-based digital elevation models (DEMs).
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