The Array module used to manipulate mathematically one, two, or a series of block, sisim, contour, or surface 2D or 3D grid files (For valid file formats, refer to Chapters 11 and 13). Depending on the options selected, operations include addition, subtraction, multiplication, division, averaging, minimum, maximum, probability value within a range, reclassification, and basic statistics. These are basic grid tools used in Geographical Information Systems (GIS). This tool can be useful for data preparation, or for data and result analysis. For example, by reclassifying a contaminant plume map to a cost of remediation map, estimates can be made about site clean up costs.

The array application is composed of two sections (Figure 17.1); the main menu- bar, and the text status area. The menu-bar is used to select all array commands and the text area contains relevant data about the status of the program or the state of on- going calculations.

NOTE: Within this chapter, any time an array is refered to, a 2D an or 3D grid is implied. This program does not perform matrix algebra.

NOTE: For correct results on operations with two or more grids, all the grids must have exactly the same grid dimensions (i.e. the number of columns, rows and layers must be the same).

Figure 17.1

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Save Preferences:

WARNING: if "array.prf" already exists, you will be warned that it is about to be over-written. If you do not want the old version destroyed you must move it to a new file (e.g. the UNIX command mv array.prf array.old.prf would be sufficient). When you press OK the old version will be over-written! This cannot be done currently from within the application. To rename the you will have to execute the UNIX mv command from a UNIX prompt in another window.

Quit:

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Figure 17.2

Once an input file has been specified, or the output file has been calculated, the text file may be edited/viewed by pressing the appropriate Edit button. A map of the file may also be displayed by pressing the Block, Contour, or Surface buttons.

Array-Constant:

Figure 17.3

Once an input file has been specified, or the output file has been calculated, the text file may be edited/viewed by pressing the appropriate Edit button. A map of the file may also be displayed by pressing the Block, Contour, or Surface buttons.

Array-Indicator:

NOTE: This option is not yet installed!

Array-Reclassification:

Figure 17.4

Once an input file has been specified, or the output file has been calculated, the text file may be edited/viewed by pressing the appropriate Edit button. A map of the file may also be displayed by pressing the Block, Contour, or Surface buttons.

Array-Series:

Figure 17.5

Once an input file has been specified, or the output file has been calculated, the text file may be edited/viewed by pressing the appropriate Edit button. A map of the file may also be displayed by pressing the Block, Contour, or Surface buttons.

Array-Point Parameters:

NOTE: This option currently does not work on single, non-series files. The program can be fooled by putting a number in the filename, and setting the First and Last series number to the same number.

Figure 17.6

The X, Y, and Z Point Location must also be specified. The output file will be of the same type as the input file. By default, a new file will be created (an old file, if it exists, will be overwritten), and the value(s) at the designated location will be printed each time this option is calculated. It is sometimes convenient to combine the results of several searches into a single file, and identify the X, Y, and Z coordinates. These options can be selected by toggling the Append to Existing File and/or Print X, Y, Z buttons. To perform the operation, press the Calculate button. When the calculation is complete, the operation will be posted in the log status window (Figure 17.1), and the results will be saved to the specified Output Array file.

NOTE: When determining the value at a particular location, different methods are applied depending on the file type. If the grid is node centered, a point falling anywhere within the node will be assigned the node value (i.e., there is no interpolation). If the grid is grid centered, the point of interest will be estimated using a basis function based on the four surrounding grid points.

Once an input file has been specified, or the output file has been calculated, the text file may be edited/viewed by pressing the appropriate Edit button. A map of the file may also be displayed by pressing the Block, Contour, or Surface buttons.

Array-Transform:

NOTE: This option is not yet installed!

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NOTE: Only one help window may be open at a time.

Help files are editable ASCII data files; for further information see Appendix D.

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geo.iso.cert.srf:

This map shows the certainty that the modeler knows what the material type will be a any location within the map area.

conc.iso.mean.srf:

This map shows the mean contaminant concentration for the flow models. Concentrations vary between 0 and 1000 ppm, and the EPA drinking water standard is 10 ppm.

conc.iso.std_dev.srf:

This map shows the standard deviation contaminant concentration for the flow models.

By modifying and combining these maps we can determine several things. By adding two standard deviations to the mean at each location, the maximum concentration with a 95% certainty can be calculated. By combining this with the geologic certainty map, after some manipulation, areas of high geologic uncertainty, and areas near the 10 ppm EPA standard can be highlighted. This is the zone of most concern for further investigation because:

1). Zones that are shown to be highly contaminated (> 100 ppm), with even further investigation will probably still exceed the EPA standard. These zones will have to be remediated, and further investigation here will do little to define the extent of the plume.

2). Zones that appear uncontaminated, are unlikely to be contaminated, and require little further exploration. It may be wise to put in observation wells to insure the plume does not migrate off site, or determine background contaminant levels, but those are different issues then being described here.

3). Zones with high geologic certainty will yield little further information with continued exploration, and the results will only minimally change the contaminant transport flow model predictions.

4). Zones with low geologic certainty, and zones near the EPA standard should be explored first. Data at these locations will best lower geologic uncertainty and define the extent of the contaminant plume.

To create these maps, use the following steps:

1). Run array.
2). Make the a file representing two contaminant concentration standard deviations.

• Select the Array:Array-Constant menu item.
  
• Define the Input Array as conc.iso.std_dev.srf.
  
• Define the Output Array as conc.iso.95.srf.
  
• Select the * Operation.
  
• Define the Constant as 2.0.
  
• Press Calculate.
  
• Press Done.

3). Make the file representing the maximum likely contaminant concentration with 95% probability.

• Select the Array:Array-Array menu item.
  
• Define the Input Array 1 as conc.iso.mean.srf.
  
• Define the Input Array 2 as conc.iso.95.srf.
  
• Define the Output Array as conc.iso.95max.srf.
  
• Select the + Operation.
  
• Press Calculate.
  
• Press Done.

This map is shown in Figure 17.7.

Figure 17.7

4). Make the exploration priority map associated with contaminant concentration. Risk will be assigned in the following manner:

• 0: 0 ppm, > 100 ppm
  
• 100: 10 ppm
  
• Values between 0 and 10, and 10 and 100 ppm will be gradational.

Reclassify concentrations:

Trim maximum concentration down to 100.0.

• Select the Array:Array-Reclassification menu item.
  
• Define the Input Array as conc.iso.95max.srf.
  
• Define the Output Array as junk1.srf.
  
• Define the Minimum as 100.0.
  
• Define the Maximum as 1000.0.
  
• Define the Reclassification as 100.0.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between 0 and 100.

Center EPA 10 ppm level about 0.0.

• Select the Array:Array-Constant menu item.
  
• Define the Input Array as junk1.srf.
  
• Define the Output Array as junk2.srf.
  
• Select the - Operation.
  
• Define the Constant as 10.0.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between -10 and 90.

Make mask; all values > 0.0 = -10.0 (This will mask out).

• Select the Array:Array-Reclassification menu item.
  
• Define the Input Array as junk2.srf.
  
• Define the Output Array as junk3.srf.
  
• Define the Minimum as 0.0.
  
• Define the Maximum as 100.0.
  
• Define the Reclassification as -10.0.
  
• Press Calculate.
  

Values now vary between -10 and 0.

Make mask; all values < 0.0 = 100.0 (This will mask out).

• Define the Input Array as junk2.srf.
  
• Define the Output Array as junk4.srf.
  
• Define the Minimum as -10.0.
  
• Define the Maximum as 0.0.
  
• Define the Reclassification as 100.0.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between 0 and 100.

Shift values from -10 to 0 to 0 to 10, then scale values 0 to 100.

• Select the Array:Array-Constant menu item.
  
• Define the Input Array as junk3.srf.
  
• Define the Output Array as junk5.srf.
  
• Select the + Operation.
  
• Define the Constant as 10.0.
  
• Press Calculate.
  
• Define the Input Array as junk5.srf.
  
• Define the Output Array as junk6.srf.
  
• Select the * Operation.
  
• Define the Constant as 10.0.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between 0 and 100.

Invert values from 0 to 90 to 0 to -90, add 100, then scale values 0 to 100.

• Select the Array:Array-Constant menu item.
  
• Define the Input Array as junk4.srf.
  
• Define the Output Array as junk7.srf.
  
• Select the * Operation.
  
• Define the Constant as -1.0.
  
• Press Calculate.
  
• Define the Input Array as junk7.srf.
  
• Define the Output Array as junk8.srf.
  
• Select the + Operation.
  
• Define the Constant as 90.0.
  
• Press Calculate.
  
• Define the Input Array as junk8.srf.
  
• Define the Output Array as junk9.srf.
  
• Select the * Operation.
  
• Define the Constant as 1.1111111.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between 0 and 100.

Add two masked data sets together to create full concentration priority map.

• Select the Array:Array-Array menu item.
  
• Define the Input Array 1 as junk6.srf.
  
• Define the Input Array 2 as junk9.srf.
  
• Define the Output Array as conc.iso.cost.srf.
  
• Select the + Operation.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between 0 and 100.

This map is shown in Figure 17.8.

Figure 17.8

5). Make the exploration priority map associated with geologic uncertainty. Risk will be assigned in the following manner:

• Values between 0.5 and 1.0 will be gradationally scaled, where 1.0 goes to 0 and 0.5 goes to 100.

  Reclassify geologic uncertainty:

  Make 1.0 --> 0.0.
  

  • Select the Array:Array-Constant menu item.
    
  • Define the Input Array as geo.iso.cert.srf.
    
  • Define the Output Array as junk1.srf.
    
  • Select the - Operation.
    
  • Define the Constant as 1.0.
    
  • Press Calculate.
    
  Values now vary between -0.5 and 0.0.

  Flip values: -0.5 --> 0.5.
  

  • Define the Input Array as junk1.srf.
    
  • Define the Output Array as junk2.srf.
    
  • Select the * Operation.
    
  • Define the Constant as -1.0.
    
  • Press Calculate.
    
  Values now vary between 0.0 and 0.5.

  Scale values between 0 and 100.
  

  • Define the Input Array as junk1.srf.
    
  • Define the Output Array as geo.iso.cost.srf.
    
  • Select the * Operation.
    
  • Define the Constant as 200.0.
    
  • Press Calculate.
    
  • Press Done.
    
  Values now vary between 0 and 100.

  This map is shown in Figure 17.9.

Figure 17.9

6). Merge two exploration priority maps into a single priority map. Note, the highest priority will be 10000 (100 x 100), an the lowest will be 0 (0 x 0).

Multiply costs by one another.

• Select the Array:Array-Array menu item.
  
• Define the Input Array 1 as conc.iso.cost.srf.
  
• Define the Input Array 2 as geo.iso.cost.srf.
  
• Define the Output Array as priority.iso.srf.
  
• Select the * Operation.
  
• Press Calculate.
  
• Press Done.
  

Values now vary between 0 and 10000.

This map is shown in Figure 17.10.

Figure 17.10

In this example both maps are scaled equally. If one map was felt more important, it could be scaled (x) first by the appropriate weight, before the two maps were multiplied together.

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Syntax:

array [-af #] [-aor #] [-cor #] [-cst #.#] [-df " "] [-fmt #] [-help] [-lgf " "] [-pmn #.#] [-pmx #.#] [-ota #] [-otc #] [-ots #] [-prf " "] [-pxyz #] [-rmn#.#] [-rmx #.#] [-runa] [-runc] [-runp] [-runr] [-runs] [-runv] [-s1f " "] [-s2f " "] [-sed #] [-sef " "] [-ssf " "] [-sst #] [-xpt #.#] [-ypt #.#] [-zpt #.#]

Meaning of flag symbols:

# = integer
#.# = float
" " = character string.
{} = variable is an array. Values must be seperated by a ',' and no spaces are allowed. Do not use the "{ }" symbols on the command line.

NOTES:

1). All parameters in [] brackets are optional.
2). Quotes must be used around character strings.

-af	=	append file	default = 0
		0 1 = = False True
-aor	=	array operation order	default = 0
		0 1 = = Array 1 ? Array 2 Array 2 ? Array 1
-cor	=	constant/array operation order	default = 0
		0 1 = = Array ? Constant Constant ? Array
-cst	=	constant value	default = 1.0
-df	=	destination file name	default = " "
-fmt	=	output file format	default = 1
		0 1 = = integer floating point
-help	=	give this help menu
-lgf	=	log file name	defalut = "log.dat"
-ota	=	array operation type	default = 0
		0 1 2 3 4 5 6 = = = = = = = add subtract divide multiply average maximum probability minimum probability
-otc	=	constant/array operation type	default = 0
		0 1 2 3 = = = = add subtract divide multiply
-ots	=	series operation type	default = 0
		0 4 5 6 7 = = = = = sum average maximum probability minimum probability probability in range
-pmn	=	minimum probability	default = 0.0
-pmx	=	maximum probability	default = 1.0
-prf	=	preference file name	defalut = "array.prf"
-pxyz	=	print X, Y, Z coordinates	default = 0
		0 1 = = False True
-rcl	=	new reclassification value	default = 0
-rmn	=	minimum range	default = 0.0
-rmx	=	maximum range	default = 0.0
-runa	=	run array-array
-runc	=	run array-constant
-runp	=	run series array-point
-runr	=	run array-reclassify
-runs	=	run series array-array
-runv	=	run MODFLOW VCONT
-s1f	=	source #1 file name	default = " "
-s2f	=	source #2 file name	default = " "
-sed	=	ending series number	default = 1
-sef	=	source series file name extension	default = " "
-ssf	=	source series file name prefix	default = " "
-sst	=	starting series number	default = 1
-xpt	=	X search location	default = 0.0
-ypt	=	Y search location	default = 0.0
-zpt	=	Z search location	default = 0.0

array -cst 5.0 -s1f conc3.srf -df junk.srf -otc 3

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