INPUTS
This command section includes all commands related to accessing and reading forest inventory data.
There are three main sources that OSM can read data from, with the first two being the most well tested and recommended:
1) SQLite (*.sqlite) database (new in 2025)
2) Microsoft Access (*.mdb, *.accdb) database
3) OLE data connections (Databases, Servers, Excel) if a full OLE connection string is used (not well tested)
Two required tables must be present in the database:
1) OSM_STANDLIST – contains stand-level attributes
2) OSM_TREELIST – contains tree-level attributes.
See input tables for a detailed description of tables and columns required.
Changing OSM input table names
Speeding up inventory record loading
Connecting to a database
using the ‘SOURCE’ command
SQLite and Microsoft Access 2002-2013 are preferred (well tested) data sources recommended when loading data to OSM through the INPUTS commands.
To connect to an access database, simply state:
INPUTS.Source “C:\MyPath\MyInventoryData.sqlite”
OR
INPUTS.Source “C:\MyPath\MyInventoryData.accdb”
Relative paths can be used. The working directory is always the same directory as the OSM command file.
For data sources other than Access or
SQLite, a fully qualified connection
string is required.
INPUTS.Source “My connection string”
Changing OSM input table
names
By default OSM will look for tables or queries named OSM_STANDLIST and OSM_TREELIST to load inventory records.
To change the OSM_STANDLIST table name to simply STANDS:
INPUTS.StandList “STANDS”
To change the OSM_TREELIST table name to simply TREES:
INPUTS.TreeList “TREES”
OSM is not case-sensitive and double quotes are only required around arguments if they contain spaces.
USA units
By default OSM assumes metric units; however, USA (English) units can be used in tables.
INPUTS.Units USA
By using the command above, OSM will convert the USA units to metric on import.
Note that to report in USA units, you must also specify the unit system in the OUTPUTS commands.
Speeding up inventory record
loading
A
column index on the SurveyID column in your OSM_TreeList table will vastly
speed record reading for large datasets (>100 tree lists). Since 2025, OSM
will try to add and index on this column for you automatically on the first
time it tries to load trees from your database.
The
screen shot below shows the index applied. You can add this manually if OSM
fails to add it during runtime.
Why is an index so important?
When SurveyID
is not indexed, OSM must read through all tree records in the OSM_TreeList table to select trees associated with the
stand to be simulated. If 100 stands are to be simulated, then OSM must scan
all OSM_TreeList records 100 times. This repeated
reading will cause an exponential slowdown to your overall simulation
processing as the number of records in OSM_TreeList
increases. This issue can be avoided by adding an index to your SurveyID column in the OSM_TreeList
table. The index allows the database to pull out records for the stand to
simulate with a single operation.