The number of green space needed to obtain a statistically sustainable amount of data to describe the quality (biodiversity and perception) to green areas in the city and peri-urban areas have been presented, and a method for measuring human perception of open spaces in the city and the periurban areas suggested (Hedblom and Gyllin, 2009). However, also in this case a main conclusion is that further development of methods is needed. This is partly because perceived experience values are hard to measure in a standardized way, and because urban areas grow both inwards and outwards which imply that green areas will disappear and new ones will emerge, which requires additional method development.