The free option may be the best bet for a fellow stay at home parent who wants to test out the survey field and confirm that money can, indeed, be earned through surveys. Download Topo Maps for iPhone from below app store link. Focus groups for a certain product or service are formed by these research companies, who then devise quite lengthy surveys to be filled out by potential consumers from those focus groups. You are comfortable with application development, scripting in various languages, as well as caring about the performance of the applications. When the linear measurements are done with a chain and a tape and the directions or horizontal angles are measured with a compass or a theodolite respectively the survey is called traversing.