[Xastir-dev] xastir-ng some use case scenarioes

[Paul J. Morris]

Not quite to the level of resolution of use cases, here are some
narrative use case scenarios and related requirements (functional and
non-functional) for discussion.  I've been working on these on the
train, and haven't had a chance to look at the wiki yet, so I don't
know how much they might duplicate anything other folks have posted
there.

-Paul


Use case scenarios

1) Who is nearby?
     An amateur radio operator with limited computer skills interested
in exploring APRS obtains a copy of xastir and installs it on their
non-internet connected computer.  They connect their TNC to the
computer, tune their radio to 144.39, and are presented with a map
showing stations nearby stations as they are heard.  The user provides
their callsign and location to xastir, and it begins transmitting their
location through the TNC.  Mobile stations are shown with their tracks,
and weather stations are shown with current weather data.  The operator
can view details of each station heard, including graphs of the weather
history for weather stations.  

1a) Who is nearby? [internationalized]
    An amateur radio operator who does not speak English downloads and
installs copy of xastir.  They connect their TNC to the computer, tune
their radio to the local APRS frequency, and are presented with a map
showing nearby stations as they are heard.  The operator provides their
callsign to xastir, connects a GPS to their computer, and provide
access information for an internet APRS server.  Xastir begins
transmitting their location over the TNC and passes both their location
and heard stations to the internet APRS server.  Xastir retrieves heard
stations from the internet APRS server and displays them on the map for
the operator.  The operator zooms in on the map, and since they have an
internet connection, satellite or aerial images of the area they are
zooming in on are shown through openareialmap's WMS service. The
operator explores stations in the area by zooming the map in and out,
by panning the map north, south, east, and west, and stays oriented to
scale by the inclusion of a scale bar on the display.  The operator
saves a local map view of the area immediately around their station,
and another map view of an area further away with lots of APRS
activity.  The operator can easily switch from one map view to the
other, or as they move around the map can move rapidly to one of the
stored map views.  

2) Resource tracking for a served agency.
    An amateur organization providing communications support for a
served agency managing a road race deploys a computer, a TNC and a
radio in the command post, and sets up map displays with the served
agency on the served agencies computers (in the command post and
elsewhere).  An operator, working with a served agency representative,
plots a route and a series of distance markers along the route.  The
route and distance markers, along with the current positions and trails
of resources that are transmitting their position by APRS are visible
both on this computer and on other served agency computers in the
command post.  

    During the event, there is a power failure, and the computers in
the command post are all shut off.  After reboot, xastir is brought
back up, and the previous session is easily restored on each
workstation, including heard stations and their trails.  

    During the event, a mobile station along the route sets its APRS
transmitter to signal an emergency, and calls in to the command post on
a voice frequency.  The status of the mobile station and its location
along the route are immediately visible on the computers that are
monitoring the map of the race in the command post.

3) GIS Asset for SAR
   A volunteer SAR organization plans to deploy a set of computers
(including laptops and mobile devices) and an xastir installation to
help provide GIS support for searches.  Members of the organization
install xastir on several of the computers, obtain a set of raster and
vector GIS layers covering their area of responsibility.  They train
with xastir as a standard GIS tool, and deploy APRS trackers with task
teams in training.  Several members of the organization's overhead team
are cross trained to use xastir and other GIS software in support of a
search.  

   GIS layers collected by the SAR organization and installed in their
xastir installations include one byte geotiff images of older USGS DRG
scanned topo quads, three byte geotiff satellite images, recent
jpeg2000 air photos, a high resolution raster digital elevation model,
vector roads from Tiger census data, geocoded placenames from GNIS,
ESRI shapefile vector layers of county boundaries, municipal
boundaries, streams, water bodies, geological hazards, wetlands, and
land use.  

   Called in to a search, the SAR organization deploys the computers
and xastir as part of its GIS support capability in the incident
command post.  Terminals are provided to logistics and operations for
monitoring resources, another to investigation for, and several, along
with a color map printer and a GIS support technician to planning.  A
video projector is also set up on a computer to allow the display of
digital maps and APRS during briefings.  APRS trackers are deployed
with task teams, including in some cases, handheld devices that serve
as APRS mapping stations.  

   During the first operational period, the GIS technician sets up the
computers and sets a default display of the search area on each.  The
technician then produces maps and 3d visualizations (draping topo maps
and air photos over the digital elevation model) of the search area for
the planning section.  As search segments are developed, they are
created as vector layers in xastir (including their initial
probabilities of area), and maps of each search segment are printed as
part of the task assignment forms developed by the planning section.
Easily available and printable information for each search segment
includes its area in acres, a UTM grid with easily read and understood
markings on the map border, a scale bar and a north arrow.  

    A decision is made to mark one search segment boundary with a flag
line along a compass bearing, so a task team is deployed with an APRS
tracker and their progress and their transit along the correct segment
boundary is monitored by operations.  The operator in the operations
section opens a map display in xastir, provides it with the tactical
call sign of the task team laying out the flag line, and sets it to
keep that station centered while the map moves around it.  The operator
leaves this map display open and opens another map display to monitor
the movements of several other task teams.  

    A task team with a tracker calls in a clue, and their voice
transmissions of compass bearings triangulating their position are
correlated with the APRS packets from their tracker providing the
investigation section a highly reliable indication of the location of
the clue.  The investigation section chief decides to send an
investigator to examine the clue, so the GIS technician marks up a map
with an automatically generated compass bearing and distance from a
nearby access point, generates and prints a map to provide to the
investigator and support team.  The investigation section chief calls
an investigator at a local police department by land line and has a
conversation with them about the clue including an URL that the other
investigator can visit in their web browser to see the location of the
clue on a map of the area.  

   As task teams return during the first operational period, their
probabilities of detection are attached by the planning section to the
search segments in xastir.  New probabilities of area for each segment
can be readily produced, and operators at each computer can easily
visualize (or print maps of) the changing coverage and probabilities of
the search area.  

   During the second operational period of the search, a county GIS
technician called in as a resource by incident command makes a set of
municipal GIS layers, including property boundaries from tax maps,
available to the search team, an operator adds these to the set of maps
being used by xastir to manage the search, and rapidly configures the
property boundaries to display as a vector layer of one pixel solid
black lines with each parcel able to be marked with the name of the
landowner.

  During the second operational period, the logistics section addresses
areas where there were radio communications problems during the first
operational period, The locations of key communications assets
including repeater locations are selected in xastir, their height,
power, and frequency characteristics are entered, and a propagation
model for is generated for each site.  Areas with poor coverage are
identified.  Based on these, a location for the deployment of a
portable repeater and digipeater is identified and tested with the
propagation model.  A communications task team is sent to deploy a
portable repeater and digipeater at this location.

    During the third operational period, a task team finds the missing
subject, their location is visible to each of the workstations.  A
rescue task team is sent in to extract the subject, this task team is
equipped with a mobile device that serves as an APRS mapping station,
so that as they proceed to the location of the find, they can see both
their current location on the map, the location of the find, and the
location of other nearby assets with trackers.  As they move around
terrain hazards, they can use the handheld to work out compass bearings
and distances to travel to most efficiently get to the find.    

4) Distributes knowledge of changing internet map services.
   The Open Street Map project resumes their WMS service and adds a WFS
service.  An xastir user becomes aware of these new services, adds them
to the list of map sources they are using in xastir, and marks these
new services as to be shared with other xastir users.  All other xastir
users have these new services automatically added to their list of
potential map sources [there are potential malicious variants of this
scenario that suggest this might be best handled in a centralized
vetted manner, such as the new services being posted to a central
source for review, and then added to a (to give a too close to
implementation example, rss) feed (to which all xastir installs can
subscribe) after human validation (which could also have updates
periodically distributed as APRS messages), though peer to peer
communication amongst xastir installs would eliminate this source as a
single point of failure].  Distribution of knowledge of changes to
weather and callsign data sources are familiar variants of the issue in
this scenario.


Functional requirements:

Runs cross platform, including mobile devices.  

Displays positions of stations heard over the air from a TNC.

Decodes APRS packets passed from a TNC.

Prints legible maps with optional north arrow, labeled UTM grid, and
scale bar.

Stores station data in a persistent manner between sessions.

Multiple displays on a single workstation.

Display on multiple workstations, including through web browsers.  

Able to display multiple forms of point, vector and raster GIS data,
including elevation rasters.  

Able to retrieve and display point, vector, and raster GIS data from
arbitrary web mapping services and web feature services.

Allows a user to draw new vector layers including at least points,
polygons and polylines along with specification of feature attributes.

Includes default global base maps.

Internationalization - User interfaces controls and documentation
provided in multiple languages and character sets.  

Generates APRS packets for transmission from a TNC.

Transmits position through a TNC, but only when given an amateur
callsign for station identification.

Retrieves station locations from internet APRS servers.

Transmits position and heard stations to internet APRS servers.

Support for OGC standards including KML and those for web mapping
services (WMS), web vector services (WFS), and sensor data (SMS).

Non-Functional requirements:

Well organized and documented code base for development and maintenance
by volunteer development team.

Open source software incorporating only compatibly licensed open source
libraries.

-- 
Paul J. Morris
Biodiversity Informatics Manager
Harvard University Herbaria/Museum of Comparative Zoölogy
mole at morris.net  AA3SD  PGP public key available