Description:

basairunitnetworkdataset 0.4.0

BAS Air Unit Network Dataset
Management of the network of routes and waypoints used by the British Antarctic Survey (BAS) Air Unit.
Including a utility to process routes and waypoints for use in handheld and aircraft GPS devices used by the Air Unit.
Overview
Purpose
To support the BAS Air Unit manage their network of routes and waypoints such that:

information is internally consistent, through defined structures and constraints
information is interoperable between different systems, through the use of open/standard formats
information is well described and sharable with other teams, through distribution as datasets (through the
Ops Data Store 🛡 for example)

Note: This project is focused on needs within the British Antarctic Survey. It has been open-sourced in case it's
of use to others with similar or related needs. Some resources, indicated with a 🛡 symbol, are not accessible publicly.
Background
This project was developed in response to discussions and requests with the BAS Air Unit to review and simplify the
process they used to manage their network of waypoints, and to ensure its future sustainability.
BAS staff can read more about this background in this
GitLab issue 🛡.
Status
This project is a mature alpha. This means:

all, or parts, of this project:

may, but should not, stop working (due to regressions or instability)
may not work correctly, or as expectedly (including destructively)
may change at any time (in terms of implementation or functionality)


documentation may be missing or incorrect
support for this project is provided on a best efforts / 'as is' basis
outputs from this project should not be relied upon for operation use without thorough scrutiny

Limitations
This service has a number of limitations, including:

the Air Unit Network utility does not support multiple, or additional, networks
the Air Unit Network utility does not require route names to follow the required naming convention
the Air Unit Network utility does not require waypoint identifiers to be unique across all waypoints
the Air Unit Network utility does not require waypoint comments to follow the required GPX comment structure
the Air Unit Network utility does not require waypoints within imported routes to be listed as standalone waypoints
comments for waypoints use an overly complex structure to support an ad-hoc serialisation format within GPX files
Unicode characters (such as emoji) are unsupported in route/waypoint names, comments, etc.
CSV outputs are not designed for printing (i.e. column formatting and page breaks)

Some or all of these limitations may be addressed in future improvements to this project. See the project
issue tracker 🛡 for details.
Usage
Loading features from GPX files
If using a GPX file to load waypoints and routes into a network, for waypoints these requirements must be met in
addition to the constraints from the Information Model:

the GPX comment field should consist of 5 elements, in the order below, separated with a vertical bar (|):

name: a full, or formal name for the waypoint (maximum 17 characters)
co-located with: name of a related depot, instrument and/or other feature - use N/A if not relevant
last accessed at: date waypoint was last accessed in the form YYYY-MM-DD - use N/A if unvisited
last accessed by: pilot that that last accessed waypoint - use N/A if unvisited
comment: any other information - use N/A if not relevant



For example (a co-located, previously visited, waypoint with a full name and additional information):

identifier: ALPHA
comment: Alpha 001 | Dog | 2014-12-24 | CW | Bring treats.

For example (a standalone, unvisited, waypoint with no full/formal name or additional information):

identifier: BRAVO
comment: N/A | N/A | N/A | N/A | N/A

Note: Only the 'name' in a comment will be included in FPL waypoints.
Creating outputs
See the tests/create_outputs.py for an example of converting a set of input waypoints and
routes into output formats, creating an Output Directory, using an instance of the
MainAirUnitNetwork class.
The Network class (on which the MainAirUnitNetwork class is based) includes a built-in method for loading features
from a GPX file (used in the example above). To load data from other data sources, construct Waypoint and Route
features directly and add to the Network class.
Output directory
When using the MainAirUnitNetwork class from this project to process waypoints and routes, an output directory
similar to the example below will be created. This directory should be held in a suitable location where all relevant
users can access it.
A typical/example output directory:
/path/to/output/directory
├── CSV
│ ├── 00_WAYPOINTS_DDM_2023_12_03.csv
│ └── 00_WAYPOINTS_DD_2023_12_03.csv
├── FPL
│ ├── 00_NETWORK_2023_12_03.fpl
│ ├── 01_BRAVO_TO_ALPHA.fpl
│ ├── 02_BRAVO_TO_BRAVO.fpl
│ └── 03_BRAVO_TO_LIMA.fpl
└── GPX
└── 00_NETWORK_2023_12_03.gpx

Access control
The Air Unit Network utility does not include access control. If needed, access controls should be applied to the
output directory, as is the case for the Ops Data Store 🛡 for
example.
Implementation
This project consists of:

a description and schema for the main BAS Air Unit travel network (routes and waypoints)
a Python library to:

import waypoints and routes from a GPX file, or other data source
export waypoints and routes into a range of output formats (currently CSV, GPX and Garmin FPL)



Information model
The BAS Air Unit Network information model consists of two entities, forming two, related, datasets:

Waypoints: Features representing landing sites used by the Air Unit, usually co-located with a BAS Operations
depot, field camp or a science/monitoring instrument
Routes: Features representing formally defined, frequently travelled, paths between two or more Waypoints, as
opposed to ad-hoc paths

For example:

Waypoints: Fossil Bluff
Routes: Rothera to Fossil Bluff

There is a many-to-many relationship between Waypoints and Routes. I.e. a Waypoint can be part of many Routes, and
Routes can contain many Waypoints.
Note: This information model is abstract and requires implementing. See the Data model section for
the current implementation.
Waypoints (information model)



Property
Name
Type
Occurrence
Length
Description
Example




id
ID
String
1
1 - ..
Unique identifier
'01G7MY680N332AW9H9HR9SG15T'


identifier
Identifier
String
1
1 - 6
Unique reference
'ALPHA'


geometry
Geometry
Geometry (2D Point, EPSG:4326)
1
-
Position or location as a single coordinate
'SRID=4326;Point(-75.014648 -69.915214)'


name
Name
String
0-1
1 - 17
Full or formal name
'Alpha 001'


colocated_with
Co-located With
String
0-1
1 - ..
Features (from other domains) associated with the waypoint
'Depot: Foo'


last_accessed_at
Last Accessed At
Date
0-1
1 - ..
When the Waypoint was last accessed or visited
'2014-12-24'


last_accessed_by
Last Accessed By
String
0-1
1 - ..
Who last accessed or visited the Waypoint
'Conwat'


comment
Comment
String
0-1
1 - ..
Freetext description or comments
'Alpha 001 is on a high ridge ...'



ID (Waypoint)
IDs:

MUST be unique
MUST NOT be based on any information contained within the Waypoint
MAY use any format/scheme:

the same scheme SHOULD be used for all IDs
non-sequential schemes are recommended



Note: This ID can be used to refer to each Waypoint in other systems (i.e. as a foreign identifier).
Identifiers (Waypoint)
Identifiers:

MUST be between 1 and 6 uppercase alphanumeric characters without spaces (A-Z, 0-9)
MUST be unique across all Waypoints

Geometry (Waypoint)
Geometries:

MUST be expressed in decimal degrees using the EPSG:4326 projection
MUST consist of a longitude (X) and latitude (Y) dimension (2D point)

Name (Waypoint)
If specified:

MUST be between 1 and 17 uppercase alphanumeric or space characters (A-Z, 0-9, ' ')

Co-located with (Waypoint)
No special comments.
Last accessed at (Waypoint)
If specified:

MUST be expressed as an ISO 8601-1:2019 date instant

Last accessed by (Waypoint)
If specified:

MUST unambiguously reference an individual
MAY use any scheme:

the same scheme SHOULD be used for all Waypoints



Comment (Waypoint)
No special comments.
Routes (information model)



Property
Name
Type
Occurrence
Length
Description
Example




id
ID
String
1
1 - ..
Unique identifier
'01G7MZB9X0R8S7RTNYAMAQKHE4'


name
Name
String
1
1 - ..
Name or reference
'01_ALPHA_TO_BRAVO'


waypoints
Waypoints
List of Waypoint entities
2-n
-
Sequence of Waypoints
-



ID (Route)
IDs:

MUST be unique
MUST NOT be based on any information contained within the Route
MAY use any format/scheme:

the same scheme SHOULD be used for all IDs
non-sequential schemes are recommended



Note: This ID can be used to refer to each Route in other systems (i.e. as a foreign identifier).
Name (Route)
Names:

MUST use the format {Sequence}_{First Waypoint Identifier}_TO_{Last Waypoint Identifier}, where {Sequence} is
a zero padded, two character, auto-incrementing prefix (e.g. '01', '02', ..., '99').

Waypoints (Route)
Waypoints in Routes:

MUST be a subset of the set of Waypoints

i.e. waypoints in routes MUST be drawn from a common set, rather than defined ad-hoc or inline within a Route


MUST be expressed as a sequence:

i.e. a list in a specific order from a start to finish via any number of other places


MAY be included multiple times

i.e. the start and end can be the same Waypoint, or a route may pass through the same waypoint multiple times



Data model
For use within the Python library included in this project, and as a reference to implementors for storing entities, a
data model implementing the Information model is available. For the later use-case, this data model assumes the
use of a relational model, specifically for SQLite (as an OGC GeoPackage) and PostgreSQL.
This data model uses three entities:

Waypoint: Point features with attributes
Route: Features to contextualise a set of Waypoints, with attributes (such as route name)
RouteWaypoint: join between a Waypoint and a Route, with contextual attributes (such as sequence within route)

Note: This data model does not describe how entities are encoded in specific Output Formats.
FIDs
Feature Identifiers (FIDs) are created automatically for features without one. FIDs are unique auto-incrementing
integers, suitable for use as primary keys within relational database.
FIDs SHOULD be considered an implementation detail, and SHOULD be ignored in favour of ID properties (i.e. 'ID' rather
than 'FID') outside the specific technology being used.
Consequently, FIDs SHOULD NOT be exposed to end users and their values or structure MUST NOT be relied upon.
ULIDs
Universally Unique Lexicographically Sortable Identifier (ULID)s are the scheme used
for identifiers (IDs).
These IDs MAY be exposed to end users.
Waypoints (data model)
Python class:

Waypoint (single waypoint)
WaypointCollection (waypoints set)

GeoPackage layer: waypoints



Property
Name
Data Type
Nullable
Unique
Max Length
Notes




fid
Feature ID
Integer
No
Yes
-
Internal to database, primary key, auto-incrementing


id
ID
ULID (String)
No
Yes
-
-


identifer
Identifier
String
No
Yes
6
-


geometry
Geometry
2D Point
No
No
-
-


name
Name
String
Yes
No
17
-


colocated_with
Co-located With
String
Yes
No
-
-


last_accessed_at
Last Accessed At
Date
Yes
No
-
-


last_accessed_by
Last Accessed By
String
Yes
No
-
-


comment
Comment
String
Yes
No
-
-



Routes (data model)
Python class:

Route (single route)
RouteCollection (routes set)

GeoPackage layer: routes



Property
Name
Data Type
Nullable
Unique
Max Length
Notes




fid
Feature ID
Integer
No
Yes
-
Internal to database, primary key, auto-incrementing


id
ID
ULID (String)
No
Yes
-
-


name
Name
String
No
Yes
-
-



Route Waypoints (data model)
Python class:

RouteWaypoint (single waypoint in route)

GeoPackage layer: route_waypoints



Property
Name
Data Type
Nullable
Unique
Max Length
Notes




fid
Feature ID
Integer
No
Yes
-
Internal to database, primary key, auto-incrementing


route_id
Route ID
ULID (String)
No
Yes
-
Foreign key to Route entity


waypoint_id
Waypoint ID
ULID (String)
No
Yes
-
Foreign key to Waypoint entity


sequence
Sequence
Integer
No
Yes (within Route)
-
Position of waypoint within a route, value must be unique within each route



Note: Though the route_id and waypoint_id columns are effectively foreign keys, though they are not configured
as such within the GeoPackage.
Test network
A network consisting of 12 waypoints and 3 routes is used to:

test various edge cases
provide consistency for repeatable testing
prevent needing to use real data that might be sensitive

WARNING! This test network is entirely fictitious. It MUST NOT be used for any real navigation.
The canonical test network is stored in tests/resources/test-network/test-network.json and is versioned using a date
in the meta.version property. A QGIS project is also provided to visualise the test network and ensure derived
outputs match expected test data.
This dataset does not follow any particular standard or output format as it's intended to be a superset of other
formats and support properties that may not be part of any standard. Derived versions of the network in some standard
formats are also available (from the same directory) for testing data loading, etc.
Updating test network
If updating the test network, ensure to:

update the version attribute in the test network to the current date
recreate derived versions of the network as needed (for example the GPX derived output) [1]
use the network utility to generate sample exports [2]
manually verify the QGIS project for visualising the network is correct and update/fix as needed

[1]
$ poetry run python tests/create_derived_test_outputs.py

[2]
$ poetry run python tests/create_outputs.py

After running, ensure all dates in files are updated to values set in tests/compare_outputs.py.
Output formats
Supported formats
Format use-cases:



Format
Use Case




CSV
Human readable, printed reference


GPX
Machine readable, handheld GPS


FPL
Machine readable, aircraft GPS



Format details:



Format
Name
Version
File Type
Encoding
Open Format
Restricted Attributes
Extensions Available
Extensions Used




CSV
Comma Separated Value
N/A
Text
UTF-8 + BOM
Yes
No
No
N/A


GPX
GPS Exchange Format
1.1
XML
UTF-8
Yes
Yes
Yes
No


FPL
(Garmin) Flight Plan
1.0
XML
UTF-8
No (Vendor Specific)
Yes
Yes
No



Outputs produced for each format:



Format
Each Waypoint
Each Route
All Waypoints (Only)
All Routes (Only)
Waypoints and Routes (Combined)




CSV
No
No
Yes
No [1]
No


GPX
No
No
No [1]
No [1]
Yes


FPL
No
Yes
Yes
No
No



Where 'All Waypoints (Only)' outputs are produced, waypoints will be sorted alphabetically.
[1] These outputs can be produced but are intentionally excluded as they aren't used by the Air Unit. See this
GitLab issue 🛡 for details.
Output file names
Output files use an internal naming convention for all formats:



Export Type
File Name (Pattern)
File Name (Example)




Each Waypoint
N/A
N/A


Each Route
{route name}.ext
01_ALPHA_TO_BRAVO.ext


All Waypoints (Only)
00_WAYPOINTS_{current date}.ext
00_WAYPOINTS_2014_12_24.ext


All Routes (Only)
00_ROUTES_{current date}.ext
00_ROUTES_2014_12_24.ext


Waypoints and Routes (Combined)
00_NETWORK_{current date}.ext
00_NETWORK_2014_12_24.ext



Where .ext is a relevant file extension for each format (i.e. .csv for CSV outputs).
Output format - CSV
Notes:

for compatibility with Microsoft Excel, CSV outputs include the UTF-8 Byte Order Mark (BOM), which may cause issues
with other tools/applications
CSV outputs use the first row as a column names header
outputs produced for all routes use a route_name column to distinguish rows related to each route
waypoint.geometries can optionally be included as separate latitude (Y) and longitude (X) columns in either:

decimal degrees (latitude_dd, longitude_dd columns) - native format
degrees, decimal minutes (latitude_ddm, longitude_ddm columns) - format used in aviation



Limitations:

all properties are encoded as strings, without type hints using extended CSV schemes etc.
CSV outputs are not validated

Output format - GPX
Notes:

GPX outputs are validated against the GPX XSD schema automatically

Limitations:

GPX metadata fields (author, last updated, etc.) are not currently populated
the GPX comment field is set to the waypoint.name property only, as GPS devices used by the Air Unit only support
comments of upto 16 characters

Output format - FPL
Notes:

FPL outputs are validated against a custom version of the Garmin FPL XSD schema automatically
route names will use spaces instead of underscores in FPL files, as underscores aren't allowed in FPL route names

Limitations:

the waypoint.colocated_with, waypoint.last_accessed_at, waypoint.last_accessed_by and waypoint.comment
properties are not included in FPL waypoint comments, as they are limited to 17 characters [1]
underscores (_) characters are stripped from route names within FPL files (rather than the names of FPL
files), a local override is used to replace underscores with spaces ( ) to work around this limitation
FPL metadata fields (author, last updated, etc.) are not currently populated

[1] This limit comes from the specific UI shown in the aircraft GPS used by the BAS Air Unit.
FPL XML schema
A copy of the Garmin FPL XML/XSD schema, http://www8.garmin.com/xmlschemas/FlightPlanv1.xsd, is included in this
project to locally validate generated FPL outputs. This schema cannot be used for validation in its published form, as
it contains a number of invalid regular expressions. These regular expressions have been modified in the schema used
in this project, which hopefully match Garmin's intentions.
In order to produce FPL files that match those produced by earlier processing scripts used by the BAS Air Unit, a
number of other changes have been made to the local version of the FPL schema. These include:

removing the requirement for a <waypoints-table> element to be included in all FPL files (relevant to route FPLs)
removing the requirement for all <waypoint> elements within <route> elements to be included in a
<waypoint-table> element (as a consequence of the above)
altering the regular expression used for the <country-name> element to allow the _ characters

Note: It is hoped these local modifications will be removed in future through testing with the in-aircraft GPS.
See #12 🛡 for more information.
Setup
Requirements

Python 3.9+
libxml2 with xmlint binary available on Path
read/write access to a suitable location for creating a Workspace Directory

Note: As of version 0.3.0, Windows is no longer a supported operating system for running this utility.
Install Python package
It is strongly recommended to install the Python Package in a Python virtual environment:
$ python -m venv /path/to/venv
$ source /path/to/venv/bin/activate
$ python -m pip install --upgrade pip
$ python -m pip install bas-air-unit-network-dataset

Development
Local development environment
Check out project:
$ git clone https://gitlab.data.bas.ac.uk/MAGIC/air-unit-network-dataset.git
$ cd air-unit-network-dataset

Note: If you do not have access to the BAS GitLab instance, clone from GitHub as a read-only copy instead.
Poetry is used for managing the Python environment and dependencies.
pyenv is strongly recommended to ensure the Python version is the same as the one
used in externally provisioned environments. This is currently 3.9.18.
$ pyenv install 3.9.18
$ pyenv local 3.9.18
$ poetry install

Editorconfig
For consistency is strongly recommended to configure your IDE or other editor to use the EditorConfig settings defined in .editorconfig.
Dependencies
Dependency vulnerability checks
The Safety package is used to check dependencies against known vulnerabilities.
WARNING! As with all security tools, Safety is an aid for spotting common mistakes, not a guarantee of secure code.
In particular this is using the free vulnerability database, which is updated less frequently than paid options.
Checks are run automatically in Continuous Integration. To check locally:
$ poetry run safety check --full-report

Static security scanning
Ruff is configured to run Bandit, a static analysis tool for Python.
WARNING! As with all security tools, Bandit is an aid for spotting common mistakes, not a guarantee of secure code.
In particular this tool can't check for issues that are only be detectable when running code.
lxml package (bandit)
Bandit identifies the use of lxml classes and methods as a security issue, specifically:

Element to parse untrusted XML data is known to be vulnerable to XML attacks

The recommendation is to use a safe implementation of an XML processor (defusedxml) that can avoid entity bombs and
other XML processing attacks. However, defusedxml does not offer all the methods we need and there does not appear
to be such another processor that does provide them.
The main vulnerability this security issue relates to is processing user input that can't be trusted. This isn't really
applicable to this library directly, but rather to where it's used in implementing projects. I.e. if this library is
used in a service that accepts user input, an assessment must be made whether the input needs to be sanitised.
Within this library itself, the only input that is processed is test records, all of which are assumed to be safe to
process.
Code linting
Ruff is used to lint and format Python files. Specific checks and config options are
set in pyproject.toml. Linting checks are run automatically in Continuous Integration.
To check locally:
$ poetry run ruff check src/ tests/
$ poetry run ruff format --check src/ tests/

To format files:
$ poetry run ruff format src/ tests/

Testing
Basic end-to-end tests are performed automatically in Continuous Integration to check the
Test Network can be processed via the Network Utility using the
tests/create_outputs.py.
$ poetry run python ./tests/create_outputs.py ./tests/resources/test-network/test-network.gpx ./tests/out

Test outputs are compared against known good reference files in
tests/resources/test-network/reference-outputs/ by
comparing checksums on file contents using the tests/compare_outputs.py script.
$ poetry run python ./tests/compare_outputs.py ./tests/out

Continuous Integration
All commits will trigger a Continuous Integration process using GitLab's CI/CD platform, configured in .gitlab-ci.yml.
Deployment
The Air Unit Network utility is distributed as a Python package installed through Pip from the
PyPi registry.
Source and binary packages are built and published automatically using
Poetry in Continuous Deployment.
Note: Packages for non-tagged commits will use 0.0.0 as a version to indicate they're informal releases.
To build the Python package manually:
$ poetry build

To publish the Python package to PyPi manually, you will need an API token for the BAS organisational PyPi account,
set as the POETRY_PYPI_TOKEN_PYPI environment variable. Then run:
$ poetry publish --username british-antarctic-survey

Continuous Deployment
All commits will trigger a Continuous Deployment process using GitLab's CI/CD platform, configured in .gitlab-ci.yml.
Releases

all releases 🛡
latest release 🛡

To create a release, create an issue using the release issue template and follow the included checklist.
Feedback
This project is maintained by the BAS Mapping and Geographic Information Centre
(MAGIC), contactable at: magic@bas.ac.uk.
License
Copyright (c) 2022 - 2023 UK Research and Innovation (UKRI), British Antarctic Survey.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

License

For personal and professional use. You cannot resell or redistribute these repositories in their original state.

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