Before spending money on practical on-site soil test/ investigation, it is good to find out if these tests/investigations have been carried out in the past by Government agencies. checks may reveal records of previous, close-by soil investigations. Geological data, aerial photographs, historical information and local knowledge of the site area will help a great deal.
Obtaining preliminary data is best gotten from the relevant government agency or establishment. This will ensure that you are using standardized and government recognized data for your preliminary soil investigation.
Preliminary data may not provide all the necessary information you need concerning the soil situation of your site, but it saves you the cost of starting an investigation from the scratch and at the same time providing recognized data for you to work with.