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Soil Technical Note-6

Central Great Plains MLRA Region 5
MO5 Soil Technical Note-6

October 28, 2008

Subject: SOI – National Soil Information System Legend Management and Datamapunit Development

Purpose. Provide the Central Great Plains Major Land Resource Area (MLRA) Office Region 5 (MO5) philosophy and guidance on National Soil Information System (NASIS) legend management and datamapunit development


Update and maintenance of soil survey information will be done on the MLRA soil survey area basis. Because the progress reporting and delivery systems of soil survey information is still based on political (generally county) boundaries there is a need to maintain data for individual county subsets in NASIS using the Non-MLRA Soil Survey Area (NMSSA) legend. The goal of an exact join of soil properties and interpretations across political boundaries can be achieved while maintaining the NMSSA legend. The key to achieving an exact join of properties and interpretations is in using the same datamapunit over a large geophysiographic area, not necessarily having one legend.

Non-MLRA Soil Survey Area Legends

The Soil Data Warehouse (SDW) is designed to store and deliver data by NMSSA. Development of new mapunits, revision and update of existing mapunits, and datamapunits can and should be done outside of the NMSSA legend. Doing development, revision and update work outside of the NMSSA legend prevents inadvertent deletion, corruption, and introduction of errors to the existing data. When the quality assurance review of the new and revised data is complete, it can then replace the existing data as “official” and be exported to the SDW.

MLRA Legends

If a common and all inclusive MLRA legend is developed in NASIS as the “official” MLRA legend and all editing and revision is preformed on this legend, it increases the workload when the data is refreshed to the SDW since the NMSSA legend must be kept up-to-date. The processes of identifying mapunits that are similar MLRA wide can be done with a variety of tools without the need to create and maintain both MLRA legends and NMSSA legends in NASIS.

Test Legends

MO5 has developed “test legends” in NASIS for use by the MLRA soil survey project offices. Currently these take on several different forms as they were developed at different times.

Area Symbol Area Name Area Type Name
5-1 Scottsbluff, Nebraska MLRA Soil Survey Office
5-2 Fort Morgan, Colorado MLRA Soil Survey Office
5-3 Pueblo, Colorado MLRA Soil Survey Office
5-4 North Platte, Nebraska MLRA Soil Survey Office
5-5 Garden City, Kansas MLRA Soil Survey Office
5-6 Hays, Kansas MLRA Soil Survey Office
5-7 Lincoln, Nebraska MLRA Soil Survey Office
5-8 Salina, Kansas MLRA Soil Survey Office
5-9 Clinton, Missouri MLRA Soil Survey Office
KTL999 Kansas State Test Legend MO5 Test Legends
MLRA112 MLRA 112 Test Legend MO5 Test Legends
NTL999 Nebraska State Test Legend MO5 Test Legends

The test legends are designed to be used in the following way. As a project office sees need for a new mapunit or is revising a datamapunit, that editing work should be done in the test legend. A copy of the original datamapunit is pasted, renamed (see MO5 Soil Technical Note-8), and correlated to a mapunit in the test legend. This allows for development, testing, and comparison of all properties and interpretations without danger of compromising the data and integrity of the NMSSA legend and does not require maintenance of an MLRA-wide legend. The project office staff should develop and test the datamapunits in conjunction with the state office staffs that will be affected by the proposed changes. When quality control is completed by the project office and state office, the MO will complete a quality assurance review. When all reviews are complete and everyone is satisfied with the proposed changes, the MO staff can complete the correlation of the new datamapunit to the NMSSA legend and enter the correlation notes in NASIS. The revised data is then ready for uploading to the SDW.

Datamapunit Development

The goal of exact joins across political and NMSSA boundaries are best achieved by correlating one datamapunit over a large geophysiographic area. This initially seems contrary to the way we have managed soil surveys in the past and currently manage the data in the SDW and Soil Data Mart (SDM). However, the soil survey area is now the MLRA and, just as before, the mapunits and properties should be representative of the survey area; i.e., the MLRA. When considering using one datamapunit, the initial thought is about the soil properties that drive interpretations (e.g., percent clay) and the task of selecting a representative value does not appear very difficult. However, when the rest of the interpretative groups and minor components are considered, the task becomes much more difficult. Things that need to be considered and worked out on an individual basis include changes in geology that affect the minor components, ranges in mean annual precipitation and temperature, frost free days, and ecological classes. There are tools available to assist with spatial and tabular review of soil properties and interpretations that are presented in other MO5 technical notes and guidance.


State Soil Scientist/MO Leader

DIST: SS (MO5), MO Leaders – TX – CO – ND – MN – AR