pictures/imod_logo.png

iMOD User Manual version 4.4 (html)


9.15ARR-files

The format is relatively straight-forward: it is a free-formatted file format generate by iMOD to create the input per package for iMODFLOW. For example, consider a grid with boundary conditions:

-1,1,1,1,1,1,-1
0,0,0,1,1,1,-1
0,0,0,1,1,1,-1
0,0,0,1,1,1,-1
0,0,0,0,0,1,-1

This could be encoded into an ARR grid file that would look like:

-1
5*1
-1
3*0
3*1
-1
3*0
3*1
-1
3*0
3*1
-1
5*0,
1
-1

At the end of the file, there is a list of the dimensions of the file with:

DIMENSIONS
120
132
120000.0
298000.0
240000.0
430000.0
3.4028235E+38
0
1000.000
1000.000

Variable

Format

Description

#

-

Comments

Ncols

Integer

Numbers of columns

Nrows

Integer

Numbers of rows

Xllcorner

Real

The western (left) x-coordinate

Yllcorner

Real

The southern (bottom) y-coordinate

Xurcorner

Real

The eastern (right) x-coordinate

Yurcorner

Real

The northern (top) y-coordinate

NODATA_
value

Real

The value that is regarded as “missing” or “not applicable”; this line is optional, but highly recommended as iMOD will expect this line to be declared

IEQ

Integer

Identifier to specify a uniform grid (IEQ=0) or a nonuniform grid (IEQ=1)

Cellsize_X

Real

The length of the x-side of a square cell

Cellsize_Y

Real

The length of the y-side of a square cell