Digital Harmonisation of Adjacent Analogue Soil Survey Areas - 4 Iowa Counties.

In conventional polygon based mapping in the United States, it is often found that concepts across geopolitical boundaries (i. e. counties and states) don't match; this mismatch may include both lines and named mapunits.  Of course, soils in the field do not change at these political boundaries.  These soil to soil mismatches are the result of the past structuring of the soil survey program.  For many years, soil surveys in the US were conducted on a soil survey area basis.  Most times the soil surveys areas were based on county boundaries.  Often adjacent counties were mapped years apart.  Different personnel, different philosophies of soil survey science, new concepts of mapping and the availability of various technologies all play a part in why these differences occur.  These differences maybe even more exaggerated at state lines as each state was administratively and technically responsible for the soil survey program within a given state.

We have looked at various numeric approaches to harmonise concepts for adjacent map soil survey areas (4 adjoining counties in southern Iowa) that will produce raster component maps with a probabilities of series at each point.  An example is given for four adjacent county soil survey areas in southern Iowa.