How Greenridge is made

Each of the 99 located campsites (site 41 has not been found on any map or layer) has a page built from these sources, in this order of trust. The method is printed beside the figure on every page; this is the list in one place.

• The pin. The Maryland DNR campsite GIS layer, with 14 pins moved after a check against photographs, a 2022 photo camp, the DNR topo map, and the AIMS layer; the site page says which kind of evidence placed it. Sites 57 to 63 are walk-ins at the DNR GIS points, 11 to 30 m off the closed ridge trail.
• Elevation, slope, aspect, landform, contours. The USGS 3D Elevation Program, read from its tiles and sampled 1.2 km around the pin. The landform word is a classifier’s, so a “hillside” is a slope between a crest and a floor, and the page says so.
• The horizon. The skyline around each pitch, measured in 144 directions out to 9 km from the same elevation model. Every sun time on a page is computed against that line, with the NOAA solar equations, for the year shown. The open-sky figure for stargazing is the share of the hemisphere above that line.
• Roads, surfaces, water. OpenStreetMap contributors (ODbL), as mapped at the last rebuild, which each page dates. Drive time from headquarters is the road distance at 15 mph on forest roads; the steepest grade is the maximum over 150 m windows of the final approach, indicative and not surveyed. Whether a creek runs year-round is modelled from USGS NHDPlus mean annual flow, an average rather than a gauge.
• How often a site is taken. 28 archived photographs of the headquarters sign-up sheet, read per site, season and weekday. A season is shown only when it clears a floor of three sheets; summer and winter do not yet, and the pages say so rather than estimate.
• What it looks like. 495 rendered 360-degree views, five seasons for each site, made from the elevation model, the canopy raster and the sun’s real position. They are labelled “modeled, not a photograph” wherever they appear. Photographs taken at the pitch are labelled with the date; 20 sites have them so far.
• What campers say. Traits such as “room for a trailer” or “secluded” are reported by campers, through the app or from public posts, and carry the Community label. Reported, not measured. Nothing a camper submits is shown until a person has approved it.
• The forest around the site. A field guide of 121 species with where to look and when, 67 recorded sounds, 19 landforms and 33 chapters of history, each entry with its sources listed; 9 trails with DNR’s miles, blazes and difficulty; the 44-mile driving tour; 45 places from headquarters to the nearest hospital; current notices, the burn-ban line and the hunting calendar from Maryland DNR, each dated.

Three words appear beside facts across the site and the app. Modeled: computed from public data by the method named beside it. Community: reported by campers, and said to be reported. Official: Maryland DNR’s own text or figure, with its source. A figure without a label is a mistake, and there is a page in the app’s Sources listing every method with its inputs and its known limits.

Two rules follow from this. A modeled fact is only as good as its inputs, so the inputs are dated on every page. And the site never says a campsite is available: the app shows what the sign-up sheet last showed, with the age of that photograph, and treats anything older than a day as a hint. How that reading works, including the review a person gives to any uncertain read, and the fact that names and permit numbers on the sheet are never stored.

Most of Green Ridge has no phone signal. A camping guide that needs a connection at the campsite is a guide for the drive there, so the app is built the other way round.

• Everything about a site is on the device. The site data, the terrain model behind the 3D map, the contours, the sun and sky computations, the whole field guide and the history ship inside the app and are precached by the web app on first visit. Asking what site 63 is like never makes a request.
• What needs a signal is said to need one, and dated. A fresh sheet photograph, the weather, DNR notices and other people’s photographs come from the server. When the signal is gone the app shows the last copy it has with its age, in words, rather than a spinner. The iOS app bundles the same build and updates itself when it next finds a signal.
• Nothing a camper does is lost. A photograph of the sign-up sheet, a note, a road report or a favourite made without signal waits on the device, listed under “waiting to send”, and goes when the connection returns.
• Big things arrive in steps. The 360 views stream in tiers chosen by the connection, with a still image until the first frame is ready, and the app reads iOS Low Data Mode and holds the large tiers back when it is on.
• Location is used only while the app is open. It places you on the map and tells you when you are at a site; it is never tracked in the background and never sent to the server. Any reminder the app offers is shown when you are there and the app is open, not pushed from elsewhere.

What this costs is honesty about age: the availability shown is as old as the last photograph, which in the off-season can be weeks. The page says so instead of pretending.

• Greenridge is not Maryland DNR and cannot reserve a site. Fees, hours, closures and rules are DNR’s; the FAQ quotes them with the date they were read, and headquarters (301-478-3124) is the authority.
• The 360 views are renders of the terrain, canopy and sky from public data, not photographs of the pitch. They show where the sun will be and what the ridge hides, not what the trees look like this year.
• A modeled figure is not a survey. Grades, distances and water are computed from public models at the resolution those models have, and can be wrong where the model is.
• The sign-up sheet is read by an AI model from a camper’s photograph; uncertain reads go to a person, and the structured record keeps only site numbers and dates. The original photograph is kept privately for that review.

Corrections are welcome: every site page has a form, and the field guide credits every photograph and recording it uses.