# Module BoxDif

### From MohidWiki

## Contents

## Overview

Module BoxDif has two main purposes: initialise properties fields within predefined boxes, enabling a better approximation for the initial condition; integrate values in time and space inside and between boxes, allowing computing global and zone budgets for almost every modelled variables.

The module is prepared to perform these operations for both 2D and 3D domains, allowing coupling it straightforwardly to the other modules.

Boxes can be drawn over the domain using Mohid GIS, by visually defining them as polygons and exporting them as boxes. By default Box 0 (zero) is always created, corresponding to the box containing all the points that were not included in the boxes definition. This way if box integration is requested and no boxes are defined, the output will be the integration of the entire domain.

The boxes definition is accomplished by verifying in which box is every single cell in which the domain in divided. Every cell is considered to be defined as a point, relative to the centre of the cell.

## Input

Use this keyword in the ModuleHydrodynamic and/or ModuleWaterProperties to activate the boxes integration in MohidWater:

BOXFLUXES : ..\..\GeneralData\Boxes\TagusBoxes_Nivel2.dat

Also in every property desired to output box fluxes insert

BOX_TIME_SERIE : 1

See Boxes to define the boxes in a file.

## Output

Two time series files can be generated by Module BoxDif, being distinguished by their extensions.

- *.BXF - Contains time series for fluxes across adjacent boxes
- Flux_X_Y, where X stands for the section index and Y stands for the vertical index.

- *.BXM - Contains time series for values integration within each defined box
- Box_Y, where stands for the vertical index.

## Algorithm

See Module Drawing