R-value (insulation) typical straw bale houses have very thick walls and thus are well insulated. Snow is roughly R-1 per inch. Brick has a very poor insulating ability at a mere R-0.2 per inch; however it does have a relatively good thermal mass. Note that the above examples all use the U.S. (non-SI) definition for R-value. When determining the overall thermal resistance of a building assembly such as a wall or roof, the insulating effect of the surface air film is added to the thermal resistance of the other materials. In practice the above surface values are used for floors, ceilings, and
Compactness measure of a shape One example of a compactness measure is sphericity formula_1. Another measure in use is formula_2, which is proportional to formula_3. The Polsby-Popper Test is a mathematical measure of compactness that was developed to quantify the degree of gerrymandering of political districts. A common use of compactness measures is in redistricting. The goal is to maximize the compactness of electoral districts, subject to other constraints, and thereby to avoid gerrymandering. Another use is in zoning, to regulate the manner in which land can be subdivided into building lots. Another use is in pattern classification projects so that you can classify the