geospatial-vector-veracity

Veracious geospatial vector data for use in SNAP tools.

What is this?

This repository is a place to store geospatial vector data (i.e. points, lines, and polygons) that has been validated for geographic accuracy and for place name orthography.

Why does this exist?

In the past we've encountered vector data that did not meet SNAP quality standards. For example:

• Incorrect locations off by up to ten degrees of longitude.
• Outdated place names such as Trout Lake, NT (now Sambaa K’e, NT).
• Place names that lack special characters or are sourced from files that lack the encoding for those characters, e.g. Utiagvik vs. Utqiaġvik.
• Ambiguous place names such as Moose Creek, Alaska

This repository is intended to resolve and mitigate these issues and to serve as the One True Source of GIS vector data for usage in SNAP tools and datasets.

Scope

Vector Geometries

• Now:
  • points (e.g. communities, airports, mines, military installations).
  • polygons (e.g. administrative units, watersheds, cultural and physical boundaries).
• Maybe in the future: lines (e.g. roads, pipelines).

Geographic Extent

• Pan-Arctic with an emphasis on Alaska

Beyond Scope

• This is not a complex geodatabase.
• Non-geographic data (e.g. population).
• This is not an authoritative resource, especially with respect to Indigenous place names.
• This is not a complete or "official" resource for vector data.

Data Model

Points

• Unique and concise alphanumeric id field serves as the index.
• Minimal set of geographic fields / columns.
• Coordinates extend to 4 digits of precision. 4 is the number and the number shall be 4.
• No spatially redundant points to the extent possible (i.e., points should be greater than ~1 km apart).
• Alternate and/or Indigenous names included when confirmed with a trusted third party.
• A tags field to enable web applications to pull the appropriate point location sets.
• Geographic fields to facilitate use in SNAP web applications that reference coastal distance, coastal status and nearest ocean neighbor grid cell coordinates.

Example:

	id	name	alt_name	region	country	latitude	longitude	tags	km_distance_to_ocean	is_coastal	ocean_lat1	ocean_lon1
0	AK1	Afognak	Agw’aneq	Alaska	US	58.0078	-152.768	ardac,eds,ncr	1	True	57.9202	-152.91
1	AK2	Akhiok	Kasukuak	Alaska	US	56.9455	-154.17	ardac,eds,ncr	0.8	True	57.0185	-154.305
2	AK3	Akiachak	Akiacuar	Alaska	US	60.9094	-161.431	ardac,eds,ncr	33.5	True	60.433	-162.469
3	AK4	Akiak	Akiaq	Alaska	US	60.9122	-161.214	ardac,eds,ncr	43	True	60.4169	-162.583
4	AK5	Akutan	Achan-ingiiga	Alaska	US	54.1385	-165.778	ardac,eds,ncr	1.4	True	54.1978	-165.923

Polygons and MultiPolygons

These features serve as map elements for web applications and/or as "data cookie cutters" (i.e. inputs for zonal statistics) that summarize gridded datasets over a geographic area.

• Unique and concise alphanumeric id field serves as the index.
• Convert small polygons (less than ~10 km² in area) to points.
• Retain only the necessary descriptive fields in the attribute table.
• Simplify geometries as needed, but visually verify fidelity to original precision.
• Strive to keep file sizes under 100 MB.
• Ensure that geometries are valid

Example:

id	name	region	country	area_type	geometry
USFS1	Admiralty Island National Monument	Alaska	USA	National Monument (USFS)	MULTIPOLYGON (((1144020.440 998268.375, 114401...
AKDNR1	Afognak Island State Park	Alaska	USA	State Park	MULTIPOLYGON (((112741.762 907629.893, 112720....
NPS1	Alagnak Wild River	Alaska	USA	National River & Wild & Scenic Riverway (NPS)	MULTIPOLYGON (((-122946.125 1004423.139, -1233...
AKDNR2	Alaska Chilkat Bald Eagle Preserve	Alaska	USA	State Nature Preserve	MULTIPOLYGON (((1025214.965 1174326.030, 10252...
FWS3	Alaska Peninsula National Wildlife Refuge	Alaska	USA	National Wildlife Refuge (FWS)	MULTIPOLYGON (((-600067.304 576372.255, -60005...