[MLB-WIRELESS] Tool for checking LOS between nodes

[Morgan Reed]

Hi All,

       I was a MW member some many (10+) years ago, but never actually got
around to doing anything about setting up a node (Partially lack of funds,
but mostly because there wasn't anything in LOS from that place.)

Many years on, the other day I was reminded by the DuxTel website that MW
exists. Figured I'd stick my head back in, though I'm not sure how much
activity there is in the community these days (the Website and Mailing List
archives seem to suggest it's a bit of a ghost town).

In anticipation of perhaps finally setting up a node I did some rummaging
around to try to determine what nodes were within LOS from my current
location, after an initial aborted attempt with Google Earth (seriously,
who the hell implements a pathing function which DOESN'T snap to markers,
oh and the elevation profile of a path ignores the elevation of the
coordinates provided...), I spent a bit of time cooking this up today;

https://tools.darkglade.com/mwLos/

It's pretty ugly and the code is horrible (I might fix it one day), but it
pretty much works.

The only nodes it loads automagically are the ones in the Geelong region
because that's where I live (if somebody wants to give me a full list of
the active nodes, ideally in this format
https://tools.darkglade.com/mwLos/nodes.json (or access to a database that
has the data in it) I'll happily stuff that in the back).

The chart down the bottom shows LOS (red), actual ground level elevation
(blue), the two green traces are the ground level elevation lifted 4m
(nominal height of a single storey building) and 7m (nominal height of a
double-storey building) so you can tell more or less if you actually have
LOS over surrounding buildings (at least if you're not surrounded by
highrises).

I arbitrarily picked two nodes in Geelong city for the initial start/end
point, but if you plug your lat/long/alt (height of your antenna above
ground) into the "Start" fields and hit "Update" you can then click around
the other nodes to see the terrain profile between you and them. The "End"
fields will allow you to plot to arbitrary coordinates if you want to see
something that's not already on the map.

One warning though, it won't be terribly accurate over long distances, as
the Elevation API is limited to 512 points per request, as such long
distances may be problematic (should be pretty good to ~5km though), if I
can be bothered (and assuming there's a decent path splitting algorithm
available in the APIs) I might fix that by breaking the paths down into
smaller chunks and querying them separately.

Figured it might be useful for other people.

Morgan
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