“Our Field Methods and Problems in the Central West”

Our first endeavor on arriving in an area, or learning what it is to be, is to obtain, if possible, a base map of suitable accuracy* This is seldom possible except in cases where the more recent U. S. G. S. maps are available. They do not, however, cover more than a very small part of the central west. Also, those available, which were made around 1900 are not sufficiently accurate on which to map soils. It is, in most cases then, necessary to construct a base map by means of plane table traverse. The government Land Office plats are sometimes of assistance in this respect but are not always accurate. In regularly sectionized country, such as^ prevails over most of the central west, where sections are uniform in size and angle of declination, the laying out of a traverse sheet is a relatively simple operation. Starting at the southeast corner and running a couple of lines of traverse north and south, and east and west will usually give a sheet layout on which may be plotted the section lines and land line roads. When such is the case , the use of the tripod is confined to the running of crooked roads necessitated by local topographic features, or the shooting in of drainage and railroads. We are very fortunate in that, over most of Iowa at least, it is quite common to find fences on all quarter mile lines both east and west and north and south,