Source transparency
The landscape behind every route.
Trailmark posters use an offline, founder-approved imagery catalog built from pinned public-source scenes. We do not fetch a live basemap when a customer views or orders a poster.
Primary imagery
Commercial-use terms are recorded before an image can ship.
Copernicus Sentinel-2
Our global natural-color base uses pinned Sentinel-2 Level-2A scenes. Trailmark stores the resulting approved derivatives, and each applicable product record carries the required Copernicus credit.
Copernicus legal noticeUSDA and NOAA NAIP
Selected U.S. routes use public-domain National Agriculture Imagery Program photography as a high-resolution land overlay. Kalalau uses the USDA-FSA imagery distributed by NOAA under its recorded metadata terms.
USGS NAIP archive and rightsUSGS Landsat
Selected long-corridor routes use pinned public-domain Landsat Collection 2 scenes only as transparent gap fill beneath valid Sentinel pixels. Every included scene and filled fraction is recorded in the private production manifest.
USGS public-domain statementOpenStreetMap
Canonical trail geometry is derived from reviewed OpenStreetMap relations or connected footpath graphs under the Open Database License. Digital and printed posters credit OpenStreetMap and carry its copyright URL.
OpenStreetMap copyright and ODbL
Accuracy and review
Static, traceable, and bound to the real trail.
Will and Jack approved the current canonical imagery and route-overlay sheets on August 2, 2026. That approval is bound to the exact recipe and SHA-256 hashes for every web preview and private print master. Unknown or customer-entered routes do not fall back to another imagery service.
Every applicable poster carries “Map data © OpenStreetMap · https://www.openstreetmap.org/copyright.” The same credit must remain visible at the point of sale and on Trailmark packaging or its enclosed attribution insert.
Natural Earth and U.S. Census data may be used only as shoreline and open-water masks; neither can create or move route geometry. Trans-Catalina additionally uses a modified ESA WorldCover permanent-water class to refine its shoreline.
ESA WorldCover credit: © ESA WorldCover project 2021 / Contains modified Copernicus Sentinel data (2021) processed by ESA WorldCover consortium. The permanent-water class was modified and used as a cartographic shoreline mask under CC BY 4.0.