Selection of sampling HCA’s

The urban landscape character assessment yielded a total of 33 HCA’s. In order to obtain the widest possible range of vegetation and housing densi­ties within the HCA’s to be sampled, three conditions of each of these variables were selected, namely high, medium and low. Putting these con­ditions together in all possible combinations gave rise to nine pairs of con­ditions, or cells. The data for vegetation and housing density was then scrutinized to find the nine HCA’s (out of the original 33) most closely matching these nine combinations.

Selection of control HCA’s

In order to control for differences in perception attributable to the presence or absence of the woodland setting it was decided to compare the percep­tions of Birchwood residents with those of residents of areas without this setting, as well as making comparisons between HCA’s in Birchwood with different characteristics. It was therefore decided to select three “control HCA’s” from the rest of Warrington with low, medium and high housing density, but with little or no woody vegetation.