Once the brief has been discussed and agreed with the client, a topographical survey needs to be conducted to take basic measurements, site levels and to note the location of any key features if one isn't already available. At this point, an assessment of the overall site is also be made taking into consideration things like drainage, access, the garden's topography, its environment and possibly an analysis of the soil.  For large or complex gardens or landscapes, a professional surveying company may need to be engaged, the charge for which would be presented in the fee proposal. In some instances, other types of survey may need to be initiated e.g. bat survey, tree survey.