**MO6 Guidance for Populating Acres in the Legend Overlap Tables**

Below are some basic principles to keep in mind when populating map
units and acreages in NASIS Map Unit Overlap tables:

1\. The total acres for each legend is set and cannot be changed. The
sum of all Legend acres in the state must equal the official total acres
for the state. (The sum of the parts must equal the whole).

2\. In the Legend Area Overlap table, the overlap acres for the state
must equal the Legend total acres, the sum of the county overlaps must
equal the Legend total acres, and the sum of MLRA overlaps must equal
the Legend total acres. (The sum of the parts must equal the whole).

3\. In the Legend Area Overlap table, acres for each county overlap are
firm and MUST NOT BE CHANGED. These county overlap acreages were
determined when the SSA was originally established, and were set so that
all county acreages balance statewide and equal the official county
acreages. If the sum of map unit acres in a county does not match the
county overlap acres, then the individual map unit acres need to be
adjusted- NOT the county total. (There is a validation for this: Legend:
\'Legend Acres\' validation).

4\. In the Legend Area Overlap table, the total acreage for each MLRA
CAN BE adjusted. These numbers are usually calculated after all map
units, including miscellaneous areas, are assigned to an MLRA. In
contrast to county and state total acreages, there are no official total
acreages for MLRAs. You could think of MLRA totals as \"bottom-up\"
totals, and states and counties as \"top-down\" totals.

To avoid confusion, this is the recommended procedure for populating
acreages in the Map Unit Area Overlap tables:

1\. Start with the map unit acreage report produced from the digital
soil data. If the sum of the map units does not equal the Legend total,
then adjust map unit acreages proportionally. (use common sense and keep
this simple; if you\'re only off by 10 acres, maybe adjust only the
highest-acreage map unit; if you\'re off by several hundred acres,
adjust the highest 10-20 map units, etc.)

2\. Once you have firm map unit acreages, populate these values in the
Map Unit table. Then run the validation to check (in Legend: \'Legend
Acres\' validation).

3\. Highlight all rows in the Mapunit table and then copy them. Go to
Legend Area Overlap table and the \'state\' row; go down-table and paste
in the copied rows (map units). This will paste in symbols and map unit
names but not the acreages (because the source and destination are
different tables). Map unit acres must be entered manually and must
equal the values you entered in the Mapunit table. Make sure the
\'state\' overlap does not include map units with \"additional\" status.
When complete, validate your entries (in Legend Area Overlap: \'Overlap
Acres\').

4\. For county-Mapunit Area Overlap acres: use GIS to determine the
extent of each map unit in each county. Adjust these numbers so that the
sum for each county equals the allowed county total (as given in Legend
Area Overlap) AND the sum of the MU acres in each county equals the
total map unit acreage (as you populated in Mapunit table). An Excel
spreadsheet can be a great help. Populate these numbers in Mapunit Area
Overlap under the respective counties. When complete, validate your
entries (in Legend Area Overlap: \'Overlap Acres\'). A report on the MO5
NASIS Site may be helpful to display map unit overlap acres (SDQS
Mapunit VS. MU acres report).

5\. For MLRA-Mapunit Area Overlap acres: generally copy rows from the
state-Mapunit Area Overlap (from step 3) and paste under the proper
MLRA. There are two situations that require different procedures:

a\) For map units that are not solely miscellaneous land types:

Assign the map unit IN ITS ENTIRETY to one MLRA. Make this decision
mapunit by mapunit, based on its physiographic characteristics. (Consult
Ag. Handbook 296 or the MO office if you are unclear as to what the
correct MLRA association should be.) Copy-paste is a timesaver here, and
is possible because all map units and acres were populated under the
state in step 3, providing a validated source for copying. Symbols, MU
names, AND acres can be copied and pasted between overlap tables.

b\) For map units that are solely miscellaneous land types (e.g. Water):

Apportion the map unit acreage into the proper MLRAs and populate the
Mapunit Area Overlaps accordingly. GIS is helpful for this, using a
process similar to the county-mapunit overlap analysis. As with
counties, the sum of the parts must equal the whole- the sum of Water
acres in each MLRA must equal the total acreage of Water.

6\. Total up the map unit acreages for each MLRA and enter this number
in the Legend Area Overlap table. (As noted above this is one of the
values in Legend Area Overlap that you are permitted to change.) When
complete, validate your entries (in Legend Area Overlap: \'Overlap
Acres\').