GMS:Units: Difference between revisions

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When building a ground water model, it is important to ensure that consistent units are used when entering model parameters. To simplify the management of model units, the user can define the units for length, time, mass, force and concentration in the '''Units''' dialog. A units label is placed next to each of the input fields in all the model dialogs in GMS where the units are known. For example, the units for hydraulic conductivity are length / time. If the length units are defined as "m" (meters) and the time units are defined as "d" (days) in the '''Units''' dialog, then the units string next to the hydraulic conductivity input field would be "m/d".
[[File:GMSunits.png|thumb|250 px|The ''Units'' dialog.]]
When building a ground water model, it is important to ensure that consistent units are used when entering model parameters. To simplify the management of model units, define the units for length, time, mass, force, and concentration in the ''Units'' dialog. A units label is placed next to each of the input fields in all the model dialogs in GMS where the units are known. For example, the units for hydraulic conductivity are length / time. If the length units are defined as "m" (meters) and the time units are defined as "d" (days) in the ''Units'' dialog, then the units string next to the hydraulic conductivity input field would be "m/d".


Concentration units can be defined separately, and potentially inconsistently with, mass and length units. This allows for more flexibility but can also lead to confusion so you should use care when selecting concentration units.
''Length'' units are specified in the [[Projections|''Display Projection'']] dialog which is accessed by clicking on the [[File:Dot dot dot button.png|28px]] button to the right.
 
Concentration units can be defined separately, and potentially inconsistently with, mass and length units. This allows for more flexibility but can also lead to confusion so use care when selecting concentration units.
 
The ''Units'' dialog is accessed by using the '''Units...''' command in the ''Edit'' menu.


==Unit Conversion==
==Unit Conversion==
'''Generally speaking, GMS does not convert quantities from one system of units to another. GMS only displays the chosen units to help the user make sure they are being consistent.''' However, in a few places, such as in the [[GMS:FEMWATER_Model_Input#Fluid_Properties|FEMWATER Fluid Properties dialog]], the [[GMS:FEMWATER_Model_Input#Curve_Generator|Curve Generator dialog]], and when calculating the stream stage constant when saving MODFLOW, GMS will use the currently defined units in it's calculations.
 
Generally speaking, GMS does not convert quantities from one system of units to another. GMS only displays the chosen units to help in checking consistency. However, in a few places, GMS will use the currently defined units in its calculations. These include:
 
* in the [[GMS:FEMWATER_Model_Input#Fluid_Properties|''FEMWATER Fluid Properties'']] dialog,
* in the [[GMS:FEMWATER_Model_Input#Curve_Generator|''Curve Generator'']] dialog,
* when calculating the stream stage constant when saving MODFLOW, and
* in the [[GMS:Toolbars#Static_Tool_Palette|'''Measure''']] tool.


==See also==
==See also==


*[[GMS:The Edit Menu|Edit Menu]]
*[[GMS:Edit Menu|Edit Menu]]


{{Navbox GMS}}
{{Navbox GMS}}


[[Category:GMS General Information]]
[[Category:GMS General Information]]
[[Category:GMS Dialogs|U]]
[[Category:Preferences]]

Latest revision as of 17:22, 14 March 2022

The Units dialog.

When building a ground water model, it is important to ensure that consistent units are used when entering model parameters. To simplify the management of model units, define the units for length, time, mass, force, and concentration in the Units dialog. A units label is placed next to each of the input fields in all the model dialogs in GMS where the units are known. For example, the units for hydraulic conductivity are length / time. If the length units are defined as "m" (meters) and the time units are defined as "d" (days) in the Units dialog, then the units string next to the hydraulic conductivity input field would be "m/d".

Length units are specified in the Display Projection dialog which is accessed by clicking on the Dot dot dot button.png button to the right.

Concentration units can be defined separately, and potentially inconsistently with, mass and length units. This allows for more flexibility but can also lead to confusion so use care when selecting concentration units.

The Units dialog is accessed by using the Units... command in the Edit menu.

Unit Conversion

Generally speaking, GMS does not convert quantities from one system of units to another. GMS only displays the chosen units to help in checking consistency. However, in a few places, GMS will use the currently defined units in its calculations. These include:

See also