LightListManager User GuideLocal Notice to Mariners (LNM) in LightListManager
This section covers using LightListManager to display the LNM status for each entery in the USCG Light List. With version 1.11.1.0 a new column has been added to the listview on the main form as shown in Fig 1. (red ellipse). The LNM data comes from a xml file that is published on the USCG website. This file contains the principle data from the Discrepancies and Temporary Changes sections of the LNM document. According to the documentation on the USCG website this file is updated daily; however, it appears that is not always the case. I think the updates are published on the day an entry is added or removed from the file, rather than holding updates for the weekly publishing schedule. Continued use of this program feature may provide more information on the file updates
The controls for downloading the LNM file are located at the top of the main program form as shown in Fig 2. The download date and reporting week of the LNM file are displayed in the text boxes. The file is downloaded by clicking the "Update LNM" button. With the successful completion of the download the date and reporting week values will be filled in. If the user is not interested in the LNM data, do not click this button and the column will be left blank. Processing LNM data will slow down the building of the listview for large volumes to some degree. If the user downloads the file and then decides the slower display is unacceptable, use the Windows Explorer to delete the "LNM.xml" file in the LightList folder.
Displaying the LNM Status
In Figure 3, I have displayed the Volume 2 Light list and scrolled down to select several entries that have a LNM status. This selection includes one entry with a blank status.
The LNM status shown on the main form is from either the Discrepancy or Temporary Change records. If a light has both a Discrepancy and the Temporary Change, the main form will display the Discrepancy status. To see all of the LNM data for a light, use the LNM Details display.
In Figure 4 I right-clicked on the listview to activate the popup menu which now contains the "LNM Details" item
When the "LNM Details" menu item is clicked the LNM Details form appears (Figure 5) The comboboxes at the top of the form have been filled with the LLNR and Description for each selected Light List entry. The first of the entries has been selected and the LNM data for that light is shown on the form. In this case the LNM is for a Temporary Change to relocate the light for dredging. These is no Discrepancy entry for this light so only the Temporary Change is displayed.
In Figure 6 have selected another entry in the combobox and a Discrepancy status is shown. Most of the LNM entries are for either a Discrepancy or a Temporary Change, a few will include both.
LNM Contents Form
Subsequent to the initial implementation of the LNM Status in LightListManager described above, the LNM Conents form was implemented to allow investigation into the contents of the LNM xml file downloaded from the USCG web site
This form is accessed by clicking on the "LNM Contents" button as shown in Figure 7
The LNM contents form is shown in Figure 8. There are two page tabs at the top of the form, and the "Content of LNM" page is automatically selected when the form is activated.
There are two sub-pages on the "Content of LNM" page, one for "Discrepancies" and the other for "Temporary Changes". The "Discrepancies" sub-page is automatically selected. On both sub-pages are drop-down lists that select the LNM entries that will be displayed in the listing on the sub-page. The first two drop-down lists are used to specify the year and week of the LNM entries to be displayed. The third list allows the display to be limited to those entries that apply to a specific USCG District.
When this page is initially display the year and week are set to the latest week in the LNM file and the District is blank showing all LNM data for the current week for all districts.
Figure 8 shows the "Discrepancies" sub-page, the "Temporary Changes" sub-page is identical except that it will display the contents of the Temporary Changes section of the LNM file rather than the Discrepancies.
In Figure 9 I have selected year 20 (2020) and week 14 for display. This is the latest week covered by the LNM data. The Listview now displays all of the LNM Discrepancies issued for that week. The District list is blank so all of the districts are included in the listing. If I had selected only the year and left the week selection blank, then the listing would show all LNM Discrepancies issued since the first week in 2020. The "Clear" button will reset all of the drown lists to blank and the listing will display all LNMs (Discrepancies or Temporary Changes) in the current LNM file.
In Figue 10 I have selected District 7 (V3D07) from the drop downlist and the now the listing shows the most recent LNM Discrepancies issued for that District.
Figure 11 shows the Miss-Matches page. I've used this page to help me understand the conents of the LNM xml file and to help me debug the program. It doesn't provide any meaningful information to the normal user, and I will eventually remove it from the program. In the meantime I will continue to use it to help me verify that the program is correctly processing the data or if there are significant errors in the file conents. When this page is selected the program loads the contents of all Light List volumes into the program tables and then compares each LNM file entry against the contents of the appropriate volume. Any miss-matches between the LNM and Light List entries causes the LNM entry to be added to the Miss-Match listboxes, Discrepancy or Temporary Change.
The Miss-Match checks that LLNR, Light name or description and location are the same in both the LNM file and the Light List Volume. Running this verification showed me that the LNM file contains many entries for which there is no corresponding entry in the Light List. Nearly all of these are for Private Adminstered (PA) navaids, mostly in Volume 5. It was via this Miss-Match check that I discovered that all of the Volume 5 Lights in the LNM file are coded for the psuedo District 2. This apparently was done becuase the LNM file does not include the Volume number, only the District number. So the USCG needed a way to differentiate Volume 4 from Volume 5, both of which are administered by Disctrict 8. I wondered why the initial LNM Status implementation for those two volumes didn't seem correct, until I ran the Miss-Match check and discovered there was a District 2 in the LNM file. This required a small amount of work-around and exception code in the program. The program now ignores all entries in the LNM file with a missing or invalid LLNR or an invalid location. That has effectively eliminated most of the entries in the Miss-Match list boxes.