It's a map that shows the approximate boundarys of the different types of soils found in an area. It's usually made on a base such as a topographic map or arial photo to provide the user reference.

A soil scientist studies area to be mapped using avialable reference material such as topo maps, geology maps, arial photos, and existing soils surveys of nearby areas. The soil scientist then traverses the landscape in the area mapped making observations and boring auger holes at regular intervals recording the locations on a base map. The soil scientist describes the conditions encountered and makes notes regarding each observation. Landscape areas (such as sideslopes, or creek bottoms) are delineated on the map and the soils that were encountered in each area are described in a narrative. These narratives usually describe map units that describe a range of characteristics and a typical soil profile for each unit. Soils are highly variable so the descriptions can be quite broad especially on mapping projcts where the scale of mapping is large.

The soil maps are hand drawn on base maps by soil scientists in the field and later compiled by soil scientist in the office. The delineations made have to big enough to contain symbols that can be referenced in the narrative. The symbols usually contain a few letters and numbers. The smallest areas you can do that in are about the size of your thumbnail. If you put your thumbnail on a base map that is at a scale of 1:24000 (topo map scale) the area that it covers contains almost 50 acres of land. If you put that same thumbnail on a basemap with a scale of 1:2400 the area it covers is only about 1/2 acre of land. There is way more variability in the 50 acre unit than in the 1/2 acre unit. While the scale of the 1:24000 map may provide adequate accuracy for making decisions about large tracts of land with low intensity uses, it's inappropriate for small areas and intense uses. Enlarging the 1:24000 map so that scale is 1:2400 does not make it more accurate because the mapper who made the map made all the decisions about where to bore the holes and make the observations based on what was typical for the 50 acres he describing at the original scale. Often features that are critical at one scale seem insignigicant at the other.

Read the part about mapping scale first. Your county soil survey contains a wealth of useful information regarding soils in the county and interpretaions for different uses. What it might not tell you is exaclty what type of soil is on your property. It might be exactly right, fairly close, or completely wrong for any given spot on the map. This is totally related to the scale of mapping and the techniques generally employed in making the map. Have the soils on your proerty classified by a SETEC soil scientist and we can make a custom soil map at an appropriate scale for your project. We always use soils already on the legend for your county so finding out more info on a particular soil later is easy for you to do yourself if you want to.