Cross-Country Soaring 2004
User Guide 
9.4 The Slope Data Library
This section is a (somewhat technical) description of the organization and handling of data files used by Cross-Country Soaring (CCS) to create slope lift/sink. For a basic overview of slope lift/sink in reality and as simulated by CCS, see Ridge Soaring. For instructions on creating CCS slope data, see Creating and Using Slope Lift.
Overview
CCS automatically generates slope lift/sink for an area, if data for that area exists in CCS’ slope data “library” (the “Slope Data” folder). Each library file is named by its southwest corner, and each file covers an area 15 minutes, or ¼ degree, (latitude/longitude) square. For example, the library file named “N34.50W086.50.slo” contains slope data for the area N34.50° to N34.75° latitude and W86.50° to W86.25° longitude. Every library file is exactly the same size: 176KB (180,000 bytes). No library file will exist for an area until you’ve either imported scanned data for the area or you’ve directly added library files created by another user to your library. The next section discusses adding data to the library.
The second type of slope data file used by CCS is the “scan file”. This is the file created by CCS during a terrain scan. A scan file contains data within user-defined bounds, and these bounds are given in the file’s header (the first few lines of the file). Because the bounds of a scan are user-definable, a scan file can be virtually any size. A scan file may include data spanning any number of library files. A scan file is not directly used by CCS to generate slope lift/sink. Its data is only used after the file is imported into the slope data library. The next section discusses importing scan files.
NOTE: Both library and scan files are text files that can
be opened with any common text editor (e.g., Notepad).
Adding Data to the Library
The primary means of adding slope data to the library is to “import” a scan file. After each scan you perform, CCS places the resulting scan file into the folder of your choice. If you want to import and use the data right away, you should have CCS place scan files in the “Import” folder. The next time you start CCS, in any mode, any files in this folder will be imported. (You will receive a separate import confirmation message for each imported file.) You may import scan files created by others simply by placing them in your “Import” folder. CCS will automatically use the data in imported file(s) with no other action on your part. Imported slope data becomes a permanent part of the library (until overwritten or deleted), so you’ll never have to create or import this same data again.
How, exactly, does the import work? First, any time you start CCS, in any mode, any scan files in the “Import” folder are imported. Each appropriate library file will be created, if it doesn’t already exist, and will be filled with data from the imported scan file. If the imported scan file doesn’t completely cover the area described by this library file, then non-covered points will be defined as flat ground. If an affected library file does already exist, then data in the area defined by the imported scan file will overwrite the existing data for that area in the library file. Non-covered points in the library file will be unaffected.
Another method of adding slope data to the library is to directly add library files obtained from another user. This may be desirable, if the scan file the other user used to import the data is very large, and you only want data from a small part of the scan file. For example, another user may have a scan file that covers ~20,000 square miles and takes up over 10 MB of disk space. You only want data for ~1,000 square miles of this area, though, and don’t want to attempt a 10 MB download over your slow internet connection. Therefore, you ask this user for the specific six library files that cover the area you want. You’ve now cut the size of the download to only 1 MB. Simply place these files in your “Slope Data” folder, and you’re ready to fly. Use caution with this method, though, as you may already have one or more of these library files, in which case you’ll have to decide which to use.
Data Archival
One advantage of the import method (over the manual addition method) of adding data to the library is that the import method “archives” a copy of imported scan files. As each scan file is imported, it is moved from the “Import” folder to the “Import\Archive” folder. This gives you a convenient way to see what scan files you’ve imported. By giving scan files recognizable names, you can know whether or not you’ve imported data for a particular soaring site. If the name of an imported file is the same as a file already in this “Archive” folder, then the imported file’s name is made unique by appending a number to it. For example, if “my site.dat” is imported but already exists in the “Archive” folder, then the archived copy of this most recent import of “my site.dat” will be renamed “my site1.dat”. A subsequent import of “my site.dat” would result in an archive file name of “my site2.dat”, and so on.
Removing Data from the Library
If, for any reason, you want to disable slope lift/sink for an area, remove all slope data library files that comprise the area. A simple way to disable all CCS slope data, if desired, is to rename the “Slope Data” folder to any name other than “Slope Data”. CCS does not contain an “export” or “remove” function for exporting, or removing, from the library data within user-defined bounds. You must figure out which library files you don’t want and remove them yourself. Do not open a library file and delete part of its contents. The results of this would be mis-located slope lift or sink while flying.