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Table of Contents - The Atmospheric Studies Group at TRC

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Section 2: Geophysical D<strong>at</strong>a Processors<br />

<strong>The</strong>se files are directly comp<strong>at</strong>ible with the CALPro GUI. A description <strong>of</strong> the NLCD d<strong>at</strong>a set is easily<br />

accessed from http://landcover.usgs.gov/n<strong>at</strong>llandcover.php.<br />

2.2.2 CTGCOMP - the CTG land use d<strong>at</strong>a compression program<br />

CTG LULC d<strong>at</strong>a files retrieved from the ftp/web sites are ASCII files which are quite large, and it is<br />

useful to compress the d<strong>at</strong>a. CTGCOMP reads an uncompressed CTG file and produces a compressed<br />

CTG file. Both files are in ASCII form<strong>at</strong>. <strong>Table</strong> 2-4 gives details <strong>of</strong> this file form<strong>at</strong>.<br />

CTGCOMP requires an input file called "CTGCOMP.INP" in which the user specifies the uncompressed<br />

CTG land use d<strong>at</strong>a file name and the compressed output file name. A list file (CTGCOMP.LST) is<br />

cre<strong>at</strong>ed which echoes the header records <strong>of</strong> the land use d<strong>at</strong>a file and provides summary inform<strong>at</strong>ion about<br />

the run. CTGCOMP must be run for each CTG d<strong>at</strong>a file. CTGCOMP.INP may be cre<strong>at</strong>ed/edited directly<br />

using a conventional editor, or it may be cre<strong>at</strong>ed/edited indirectly by means <strong>of</strong> the PC-based, Windowscomp<strong>at</strong>ible<br />

Graphical User Interface (GUI) developed for the geophysical preprocessors (CALPRO).<br />

2.2.3 CTGPROC - the land use preprocessor<br />

CTGPROC currently supports five different form<strong>at</strong>s <strong>of</strong> Land Use d<strong>at</strong>a. <strong>The</strong> USGS Land Use and Land<br />

Cover d<strong>at</strong>a in Composite <strong>The</strong>me Grid (CTG) form<strong>at</strong>, the USGS Global D<strong>at</strong>a Form<strong>at</strong>, two generic form<strong>at</strong>s<br />

and, the N<strong>at</strong>ional Land Cover D<strong>at</strong>aset 1992 (NLCD92).<br />

CTGPROC is able to process multiple files in one run and from more than one d<strong>at</strong>a set in a single run.<br />

However, there is also the option to perform multiple applic<strong>at</strong>ions <strong>of</strong> CTGPROC, a typical example may<br />

be insufficient hard drive space to store all large ASCII Land Use files. When this option is invoked all<br />

runs must be written in a continu<strong>at</strong>ion form<strong>at</strong>, except for the final run which must be written in the<br />

fractional Land Use form<strong>at</strong> th<strong>at</strong> MAKEGEO expects as input.<br />

CALMET grid cells are <strong>of</strong>ten large enough to include more than one land use d<strong>at</strong>a point: CTGPROC<br />

keeps track <strong>of</strong> the number <strong>of</strong> process 'hits' <strong>of</strong> each land use c<strong>at</strong>egory for each grid cell and in the final run<br />

<strong>of</strong> an iter<strong>at</strong>ion compiles final fractional land use c<strong>at</strong>egories for each grid cell. A hit is a Land Use<br />

d<strong>at</strong>apoint from one <strong>of</strong> the Land Use d<strong>at</strong>asets th<strong>at</strong> falls within a grid cell defined by CTGPROC. If the<br />

number <strong>of</strong> hits for a given grid cell is less than a user-specified threshold <strong>of</strong> the domain average number<br />

<strong>of</strong> hits, the program flags possibly missing d<strong>at</strong>a in a list file (or possibly incorrectly specified domain<br />

parameters).<br />

Input: <strong>The</strong> user can access the user input control file <strong>of</strong> CTGPROC through the ‘Geophysical D<strong>at</strong>a’ on<br />

the front screen <strong>of</strong> the CALPro GUI. <strong>The</strong> control file can either be cre<strong>at</strong>ed from within the GUI or<br />

independently using an editor. <strong>The</strong> user control input file, CTGPROC.INP (whose grid definition<br />

parameters must be comp<strong>at</strong>ible with those used in TERREL), and one or more <strong>of</strong> a compressed CTG d<strong>at</strong>a<br />

file, global d<strong>at</strong>a file, NLCD d<strong>at</strong>a file or generic form<strong>at</strong> file must be read. <strong>The</strong> form<strong>at</strong> <strong>of</strong> the CTGPROC<br />

control input file follows the same rules as those used in the CALMET.INP file (refer to the CALMET<br />

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