Conventional and special AD-HOC spot symbols used for soil survey maps

These AD-HOC spot symbols are used on soil survey maps to locate special areas, features, and soil inclusions which were too small to delineate at the scale of mapping or provide useful information about an area. The minimum map unit delineations for soil surveys published at a 1:20,000 to 1:25,000 scale is 5 to 8 acres. The Plymouth County Soil Survey UPDATE (not the 1969 report) is mapped at a scale of 1:12,000 with minimum delineations of 1 to 2 acres in size.

To download the NRCS Arcview Soil Symbol Set go to:

Click HERE to download the Arcview spot symbols AVL files for Norfolk and Suffolk Counties (norfspot.avl) and Barnstable County (barnspot.avl). For more information about digital soil data for SE Massachusetts click HERE. For the MassGIS Soils datalayer description click HERE.

Link to NSSH Adhoc Symbols (Exhibit 37A)

Spot Symbol GIS Lable Description

BLD* Boulder spot - used in stony and non stony units to show the location of isolated boulders, generally greater than 5 feet in diameter and less than 30 feet in diameter, not used in bouldery map units.
CLA Clay spot - used to denote inclusions of fine textures, usually silt, clay and loamy textures within areas of coarser textured soil.
LDF Dumps and other non soil areas - used to denote small area of refuse and non soil areas.
DIS/SPO/STR** Disturbed area - areas where the original soil has been disturbed, or the topsoil has been removed.
DRY Dry spot - used only in poorly and very poorly drained map units to identify inclusions of moderately to excessively drained soil areas.
GPI Gravel Pit or Borrow Pit - used to show small active sand and gravel pits. Also used to show the location of old abandoned pits.
GRA Gravel spot - used to denote inclusions of gravelly soil material within areas of non gravelly soils.
ESO Escarpment - Soil
ESB Escarpment - Bedrock
MAR Marsh or swamp - organic soil inclusion in a mineral soil map unit.
MPI Quarry Pit - used to show small active or abandoned quarry pits (in hard bedrock).
ROC Rock outcrop - used only within very deep soil map units which are not in a complex with shallow to bedrock soils, also used for boulders greater than 30 feet in diameter.
SAN Sandy spot - used to denote inclusions of sandy soil material within areas of loamy and finer soil map units.
SLP Short steep slope, typically greater than 15 to 25 percent in a map unit less than 15 percent (A or B slopes) .



Stony and very stony spot  - used to denote stony and very stony inclusions, referring to surface stones only, within non stony map units.
STK* Stockpile, organic and topsoil - used to denote areas less than 2 acres of topsoil, tree stumps, and organic material.
TIL* Till spot - used in non till soil areas to denote areas of till, either ablation, basal, or flow till.
INW Water, miscellaneous - used for small water bodies such as intermittent ponds.
PNW Water, perennial - used for small perennial water bodies.

Wet spot - poorly or very poorly drained mineral soil in an excessively well to moderately drained soil map units.

* These symbols are used in the updated mapping of Plymouth County and NOT in adjoining surveys.

** The disturbed soil spot symbol (tic-tack-toe looking) is also labled SPO - spoil Area and STR - Stripped Area on the digitized files. It basically shows that the soils within the area have been disturbed by human activity.

Drainage Symbols (Note: the term "Stream" is used for all flowing water such as river, brook, creek, drain, etc.).

Symbol Name Description
Drainage End Drainage ends indicate the direction of flow. Compile the feature where streams end abruptly and disappear into caverns, depressions, marshes, or other areas where the stream is no longer clearly evident.
Intermittent Stream This is a stream that is dry for a large part (more than 3 months) of each year.
Perennial Stream This is a stream that flows throughout most normal years.

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