Readme file for Geoid99 grid extract utility -------------------------------------------------------------------------- Executable File Name: G99ge.exe Disclamier: There is absolutely NO WARRANTY as to values created or reliability of this program - Use at your own risk. //This program was developed from NGS FORTRAN source code Xntg.for //which was programmed by Dru A. Smith at NGS - without his code this //function could not have been written very easily. // //Many thanks to Charlie Schwarz [Charlie.Schwarz@noaa.gov] for his //assistance and patience in helping me develop the C code. //written 12-26-2000 by Terry Nygaard //updated 03-08-2002 - Fixed DMS to decimal conversion error on lat/long //Copyrighted Dec 2000 by Terry Nygaard all rights reserved //------------------------------------------------------------------------ //Using this source code or compiled executable as a part of commercial //(for profit) applications is strictly prohibited. Educational institutions //are free to use the source code as long as it is made no part of a //commercial application. Users wishing to use this code as part of a //commercial application must contact Terry Nygaard at E-mail or //E-mail or ph# 512-369-7528. Developed as an alternative to Xntg.for. 'C' code was developed with small memory requirements in mind. Unlike the Fortran code which can require a large amount of ram, this utility is very memory efficient. Code is useful for DOS or other Microsoft OS's in which memory is limited, such as WindowsCE. The big difference between this utility and Xntg.for is that it can only utilize a single *.bin file. Xntg.for by contrast can utilize many grid files. These *.bin files are NGS formatted geoid 99 geoid files. These files can be obtained at this location: http://www.ngs.noaa.gov/GEOID/GEOID99/datageo99upc1.html The basic usage is to specify a *.bin source file to extract and then a *.bin output file to create that will be a sub-grid of the primary *.bin file. The primary *.bin file entered MUST be the full path. The output *.bin file sub-grid entered must also be input as the full path. If the output file exists, its contents are overwritten. Follow the prompts for the Lat/Lon grid boundary to extract which must be within the bounds of the primary *.bin file. All Lat/Lon inputs MUST be in DD.MM format. For example a latitude of 32 degrees and one minute is input as 31.01 DO NOT input values greater than two decimal places to the right of the decimal point which represent minute values. You may input west longitudes as a negative value for example 97 degrees and eight minutes is input as -97.08 After the output *.bin file is created, geoid stats are displayed on the output file.