Population density is an example of areal number density. HDD improvements have been driven by increasing areal density, listed in the table above. The multi-threat vests have areal densities close to the sum of the two solutions separately. Generally, correlation increases as areal unit size increases. The constancy of areal velocity may be illustrated by uniform circular and linear motion. The Central and Plains, however, are groupings based on areal features and geographical proximity. Areal roughness parameters are defined in the ISO 25178 series. Any similarities to other linguistic phyla may be due to areal influences. An example of a relative geocode is address-interpolation using areal units or line vectors. Areal and trilinear coordinates are used for similar purposes in geometry. The municipality had a population of 196,538 and an areal extent of . Design shall be areal, not axial. Tone is sometimes an areal rather than a phylogenetic feature. The city of Mwanza has a city council whose areal jurisdiction overlaps two municipal councils. Barycentric or areal coordinates are extremely useful in engineering applications involving triangular subdomains.