Workfiles Created by Walls

When an item in the project tree is compiled, whether it be an entire branch or just a leaf (survey), a database consisting of a group of five binary files is generated and placed in the project's work folder.  The file names are constructed from the 8-character workfile base name (or survey file name), which is a property specified for the particular item being compiled. (See Properties: General Page).  Currently Walls creates files with the following extensions: NTA, NTAC, NTV, NTS, NTN, NTP, and (optionally) NTW.  Also, any coordinate listings (extension LST) you might want are created in the work folder.

The NTA workfiles are particularly important since they store various configuration and display settings you've assigned to the compiled item. These include the sizes and colors of map features, last-saved map view, grid intervals, and so forth. (The NTAC files, which store defined color gradients, are considered part of the NTA file set, as are gradient snapshot files with extensions NTAE, NTAD, and NTAS.) The backup archive feature therefore gives you the option of including all NTA files in the project backup. There is one catch, however. Since the NTA file format is rather complex and subject to change, it has not always been possible for a new version of Walls to read the NTA files of an older version (depending on how old). Hence the occasional need to recompile, and, in the worst case, make new display assignments. (See note below.)

How They Are Used

The database is used during Review operations.  Also, to preserve current  configuration settings, the existing NTA component is read during the recompilation of a project tree branch.  Since the entire database can be quickly regenerated (albeit with default display settings), there's no need to archive it with the all-important WPJ, SRV, and SVG source files -- except you may want to save the NTA file.  The database is self-contained and can be deleted ( Edit|Purge item workfiles...) without affecting the status of other items in the project tree.

Although each and every item in a large project tree can be compiled, this would likely be a waste of disk space since there's seldom a need to review the network geometry at every level of the hierarchy.  For example, if a book contained just one survey, compiling each (book and survey) would create separate but essentially identical databases with respect to processed data.

During review operations, however, a database is revised to also contain assigned map attributes such as grid spacing, colors, and line styles.  These assignments can get complicated for a network with numerous segments. Therefore, to get around the fact that Walls currently stores only one set of assignments in each database, you may on occasion want to insert a book node (a one-child parent) in the tree. In its database you could store a special set of assignments -- colors, for example, suitable for your printer but not the screen.  Alternatively, you can maintain a separate project tree (linked to the same survey files) for this purpose.

How Walls Keeps Track of Currency

Built into each database is a 32-bit code (checksum) constructed from the names, sizes, and last update times of all of the incorporated survey text files.  When Walls opens a project, it scans the disk to determine whether databases are up-to-date and colors the respective project tree icons accordingly (blue if up-to-date).  Walls updates these icon colors automatically as you edit files, rearrange the tree, attach/detach branches, etc.  Simply reordering children will not cause a parent's icon to change color, since the particular order that survey files are encountered in a branch traversal -- either in compilation or in computing the checksum -- is considered irrelevant.  Actually, order is not completely irrelevant. Flag symbol priorities and the assignment of the default reference station can be affected. To be sure such changes are reflected in your workfiles you can force a recompile by selecting Edit | Recompile item.

Important Note: Another situation where you may need to either recompile or Edit | Purge branch workfiles is when the database format is revised by a new program release. The program should be able to detect this situation and issue an appropriate message if certain settings need to be reinitialized to their default values.