Checking the Description File

Neighbor for all Marks

This check is accessed from the Web Tools tab (see above). Running “neighbors” identifies and lists all marks currently in the NGS database that are within a specified distance from each mark in the description file (based on the position data in each mark’s description).

Accessing the “Neighbor for all Marks” check in WinDesc

Default maximum radius for checking neighboring marks in WinDesc

Option to include TBMs (Temporary Bench Marks) in the WinDesc neighor analysis

The output is a text file (*.nbr) that lists all marks within the specified distance, sorted from nearest to farthest. If the mark already exists in the NGS database, the mark should appear at the top of the list. Note that there can be a slight discrepancy in the distance if the new position is of higher accuracy and precision than what is in the database. This is especially true for marks with scaled coordinates in the database.

The result of a neighbor analysis in WinDesc

Running neighbors is required to make sure that the user has correctly identified the mark. This is especially important if the mark is part of a set of classical horizontal marks, which may include the horizontal mark itself, as well as reference marks and azimuth marks: all marks in the set may share much of the same designation, which can easily cause confusion and mis-identification (e.g. confusing a reference mark for the horizontal mark itself). Review the information to make sure the correct mark has been included in the description file. The output table is sorted by distance from the input mark’s position to the position of nearby marks in the NGS database. The *.nbr file is saved to the same directory as the description file itself.

Discrep for all PIDs

This utility identifies and flags all discrepancies between information in the NGS database and the description file. This ensures that the user is made aware of how the new description file may differ from published datasheets. Common causes for discrepancies include newly identifying the mark as good for satellite observations, or a better source for the horizontal data.

Accessing the Discrepancy analysis in WinDesc

The output of Discrep is a text file (*.dis) with only those attributes listed that are at variance with the NGS database. The left column is for the new description, the right column is for information currently in the database. In the example, no discrepancies are found for CALVERTON, NBS 102, or BRUNSWICK 2. However, GORF N shows a discrepancy in the designation. Since it’s a published mark with a PID, the database designation is correct and the Windesc file’s designation is in error and must be corrected. All discrepancies must be considered. Re-run Discrep after all changes, if any, are made.

Remember, a discrepancy is not necessarily an error, but a warning. Your report should indicate that you have run, checked, and verified all discrepancies in the (*.dis) file.

Sample Discrepancy report showing differences between the description file and information in the NGS IDB

The *.dis file is saved to the same directory as the description file itself.

Caution

Discrepancies do not necessarily mean errors. Verify to make sure any discrepancy is indeed correct.

Recovery Dates for All Marks

Although not required by OP, this is a recommended check to verify that a recovery has not already been loaded for your project, or for another project within the same calendar year. NGS will not publish multiple recoveries within a given calendar year, unless the status of the mark has changed (e.g. from good to poor condition, or from “mark not found” to “found in good condition”).

Checking recovery dates for all marks in the description file

Exporting the Description File and Error Checking

The final steps in preparing the description file involves converting it into a format required for loading into the NGS database, and running a final error check. The export functionality will convert the native WinDesc (*.des) file format into a somewhat reduced file format readable in Linux, so the file can be loaded into the NGS IDB.

Exporting the description file

In executing the export script, WinDesc will prompt the user to run a final error check.

WinDesc prompts the user to run a final error check after exporting the description file

In the error checking process a *.err file will be created, which lists all the errors found. Typical errors include required stamping information, special characters or other errors in the designation, or additional information required for certain mark setting types. The error checking can detect logical or inconsistency errors in the mark description fields, but it cannot always pinpoint exactly what is wrong. There may therefore be several warnings or errors flagged for a particular mark (identified by its SSN). For submitting the description file to NGS (as part of the OPUS Projects GNSS project), all errors must be resolves (it is permissible to have some warnings, as shown in the example below).

Sample error (*.err) file

Warnings often request additional information pertaining to whether the mark is flush with the ground, projecting, or recessed (FPR in the example above). Other warnings might pertain to mark setting codes expecting additional information. Review the warnings to make sure you have provided correct, relevant information.

Caution

Any and all errors MUST be resolved prior to loading the description file into OP

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