Description: I am a recreational fisherman in Tarragona, Spain, and I maintain a small personal, non-commercial project that analyses fishing activity along my local stretch of coast. Nothing is published or monetised; it runs on a Raspberry Pi at home and the outputs are for my own use. I already hold an API token and I am using the Vessels, Events and 4Wings APIs successfully. Thank you for making them available - the purse seine analysis has worked very well. REQUEST dataset: public-global-all-tracks:latest endpoint: GET /v3/vessels/{vesselId}/tracks This currently returns 403 "You do not have permission to access this dataset". The request appears otherwise well formed: four different parameter combinations all return the same 403 rather than a 422. WHAT I AM TRYING TO UNDERSTAND I am studying the relationship between where the trawl fleet works and the morphology of the seabed in a small area (roughly 40.3-41.5 N, 0.4-2.1 E). Trawlers cannot work rough or rocky ground, so their spatial behaviour is an indirect record of the bottom - useful both for understanding the fishery and for choosing where to fish with rod and line from a small boat. WHY THE AGGREGATED GRID IS NOT ENOUGH I first tried this with the 4Wings apparent fishing effort grid, looking for unworked cells surrounded by heavily worked ones. It does not work, and I think the reason is instructive: at HIGH spatial resolution the cells are about 1.1 x 0.8 km, while the seabed features that stop a trawl are 80-300 m across - one to two orders of magnitude smaller. A gap in the grid is therefore not evidence of an obstruction. I tested this properly rather than assuming. I took three of the strongest candidates out to sea and surveyed them with a depth sounder and side scan sonar. There was nothing at any of the three, nor around them. The method fails, and it fails for a resolution reason rather than a tuning one. WHY TRACKS WOULD ANSWER IT With position-level tracks I could look for the signature that actually indicates a fixed obstruction: vessels altering course to steer around the same point, repeatedly, across many independent trips and over a long period. That is a minute-scale pattern and it simply is not visible in a kilometre-scale grid, at any level of filtering. SCOPE AND USE About 150 trawlers, one year of history, in the area above. I would fetch this once and cache it locally rather than polling. Non-commercial use only, under your terms, with attribution. I am happy to share back what I find about the limits of the effort grid at this scale if that is of any use to you. Thank you for considering it.
