开云体育

Greetings.

It sounds like you're viewing an area of the YAAC-imported OpenStreetMap data where there are some errors in determining ocean boundaries. Per chance, have you:

1. imported the OSM data snapshot yourself, rather than downloading from my website? and
2. used the osmcoastline utility to get the ocean boundaries?

Please let me know the approximate lat/lon of the blue squares so I can check the data there. I don't look at the entire planet on a regular basis.

Since approximately the October 2nd 2023 snapshot of OSM, there have been errors in the coastline/shoreline tagged Ways in the database where the oceans aren't decoded correctly. If the osmcoastline utility reports _any_ erroneous Ways in the dataset, then YAAC will probably import the ocean data incorrectly. So I haven't used any snapshot more recent than that to identify coastlines, even though I have used more recent snapshots for the rest of the map data (I figured that the coastlines weren't going to move much, regardless of how much highway construction was going on). When I used a more recent snapshot with osmcoastline, it put all of Europe and western Russia underwater. I'm not sure when this will be fixed in the OSM database, and I am attempting to work around it, but haven't released the latest workarounds yet.

Re: heap limits: The Java Runtime Environment virtual machine allocates a certain limited amount of heap memory for running the YAAC program (if you don't specify the -Xmx command line option, it defaults to half the physical RAM on your system). All the YAAC code, JRE library code, and third-party library code in use, plus all the data objects manipulated by this code are allocated memory from the heap. So, you can have a heap shortage if YAAC is trying to hold too much data in memory. The YAAC OSM Importer is an extreme heap pig, trying to use the heap to cache data to reduce the amount of disk I/O when importing the OSM data. However, you can over-demand your available heap without running the OSM Importer if any of the following conditions apply:

1. You are displaying topographic terrain data on the map (a certain amount of the terrain data in use is cached in heap for more efficient rendering). This gets worse if you chose to use 1-arc-second resolution data (takes up 9 times as much heap per 1-degree square as 3-arc-second data).
2. You have very large raster images superimposed on the map.
3. You are using an APRS-IS connection with either a very wide filter or an unfiltered connection, such that YAAC is having to keep track of the state of multiple thousands of APRS stations and objects.
4. You have YAAC configured to have an long in-memory retention interval for historical data about stations and objects (more data in heap per station for long-life-span heard stations).
5. You are running YAAC with an undersized heap for your use case (for example, half the RAM on a Raspberry Pi 2 is only 128MB).

Those heap error messages come out when YAAC detects that the heap is near its limit. Because the default behavior for Java is to crash if heap garbage collection (the process of reclaiming heap memory that is no longer being used) happens excessively (i.e., YAAC keeps needing to allocate more memory, but there isn't enough unused heap even after forcing a garbage collection), YAAC tries to take action to keep the heap under control before the Java runtime crashes. YAAC's behavior in this case is to shorten the in-memory retention interval (reason#4 above) so that more not-quite-as-old APRS packets can be garbage collected and thereby free up more heap before the heap state reaches critical. The "heap error" message is displayed when this happens so you know you're losing in-memory data.

Hope this helps.

Andrew, KA2DDO
author of YAAC
________________________________________
From: [email protected] <[email protected]> on behalf of W4ACR-Randy Shell
Sent: Wednesday, December 20, 2023 10:14 AM

Hello,
??????I have a couple of questions.

1. Why are some of the grid squares shaded blue? And can they be removed?
2. How do i correct heap limit errors?

Andrew,
? ? ? ? ? ?First thank you for replying. And the answer to your first two questions are yes and no.
The grid squares that I have noticed with the blue conditions are (these are coordinates with in the square)
1. 35 29.55N - 84 22.08W
2. 33 30.42N - 87 32.01W
3. 33 29.15N - 96 32.70W

I am brand new to YAAC and have most likely caused most of these issues trying to learn what is what and for that i apologize.