# Ojai–Ventura–San Diego geography

Retrieved 27 September 2026. GeoJSON uses `[longitude, latitude]` in EPSG:4326. These are public geographic labels and a mapped river centerline; no operational or private information is included.

## Ready-to-use files

- [coastal-landmarks.geojson](coastal-landmarks.geojson): eight distinct labels with coordinate and identity provenance per feature.
- [coastline.geojson](coastline.geojson): clipped and simplified coastline, including Channel Islands and a separately attributed Mexican supplement.
- [ventura-river-centerline.geojson](ventura-river-centerline.geojson): one continuous north-to-south line, 465 original vertices.
- [ventura-river-nhd-original.geojson](ventura-river-nhd-original.geojson): unchanged USGS response, 78 named reaches and 542 vertices including shared endpoints.
- [geography-receipt.json](geography-receipt.json): river connectivity check, endpoints, source length, and file hashes.
- [coastline-receipt.json](coastline-receipt.json): coastline counts, processing, source-query references, and the bundled coastline hash.
- [military-selected-source.json](military-selected-source.json) and [ojai-source.json](ojai-source.json): selected official coordinate attributes and the Ojai query response. Their exact source requests are [military-source.json.url.txt](military-source.json.url.txt) and [ojai-source.json.url.txt](ojai-source.json.url.txt).

## Landmarks

| Display label | Latitude | Longitude | Coordinate basis | Name confirmation |
|---|---:|---:|---|---|
| Ojai | 34.4491994 | -119.2466643 | Census incorporated-place internal point, GEOID 0653476 | [Census incorporated places](https://tigerweb.geo.census.gov/arcgis/rest/services/TIGERweb/Places_CouSub_ConCity_SubMCD/MapServer/4) |
| Ventura River estuary | 34.27407098 | -119.30700396 | Southern endpoint of the connected, named USGS river line | [California Water Board river description](https://waterboards.ca.gov/losangeles/water_issues/programs/tmdl/docs/R12-011_RB_RSL.pdf) |
| NBVC · Port Hueneme | 34.1622012 | -119.2083238 | Census military-installation internal point, GEOID 5537 | [Official Navy overview](https://cnrsw.cnic.navy.mil/Installations/NAVBASE-Ventura-County/About/) |
| NBVC · Point Mugu | 34.1136442 | -119.1136468 | Census military-installation internal point, GEOID 5529 | [Official Navy overview](https://cnrsw.cnic.navy.mil/Installations/NAVBASE-Ventura-County/About/) |
| Camp Pendleton | 33.3775132 | -117.3885943 | Census military-installation internal point, GEOID 3449; inland representative point of the large coastal base | [Official Marine Corps coastal setting](https://www.pendleton.marines.mil/Staff/Principal-Staff/Environmental-Security/) |
| Naval Base Point Loma | 32.6962253 | -117.2457412 | Census military-installation internal point, GEOID 5489 | [Official Navy overview](https://cnrsw.cnic.navy.mil/Installations/NAVBASE-Point-Loma/About/) |
| Naval Base Coronado · North Island | 32.6986092 | -117.2087894 | Census record “Naval Base Coronado,” GEOID 5449, located on North Island; does not represent all separated NBC sites | [Official Navy constituent installations](https://cnrsw.cnic.navy.mil/Installations/NAVBASE-Coronado/) |
| Naval Base San Diego | 32.6784656 | -117.1230936 | Census military-installation internal point, GEOID 5505 | [Official Navy installation page](https://cnrsw.cnic.navy.mil/Installations/NAVBASE-San-Diego/About/Mission-and-Vision/) |

Military coordinates are the unmodified `INTPTLON` and `INTPTLAT` values from the [US Census TIGER military-installations layer](https://tigerweb.geo.census.gov/arcgis/rest/services/TIGERweb/Special_Land_Use_Areas/MapServer/3). They are suitable for site labels, not gates, berths, navigation, boundaries, or survey precision. Displaying four decimal places is sufficient. LA/Long Beach ports were omitted to keep the map restrained and the labels distinct.

## Ventura River geometry

Primary source: [USGS NHD, Flowline – Large Scale, layer 6](https://hydro.nationalmap.gov/arcgis/rest/services/nhd/MapServer/6). The exact download query is retained in `ventura-river-nhd-original.geojson.url.txt` and inside the derived GeoJSON. Selection was `gnis_name = 'Ventura River'`, with all original fields, original geometry, and server output projection EPSG:4326. Every returned feature has GNIS identifier `00250984`.

The 78 reaches form one connected chain: 77 shared junctions have degree two and exactly two endpoints have degree one. No joining distance, smoothing, simplification, invented bridge, or manual route was needed. The derived line merely orders the segments north to south and removes duplicated shared endpoints. The summed source length is 26.14362382 km. It extends from `[-119.29971152319942, 34.485280121701344]` near the Matilija/North Fork confluence to `[-119.3070039579756, 34.27407098040758]` at the estuary.

Source feature dates are 2021-04-21, 2021-06-28, and 2023-03-30. They describe stored hydrography, not a fresh image or present-day flow measurement. NHD includes stream/river and artificial-path features through waterbodies. The latter are topological centerlines, not manufactured channels. Original coordinates are preserved; numerical digits do not imply survey accuracy.

Ojai city center lies east of the Ventura River. Show the city as a separate marker. Do not draw an invented river through Ojai or a physical ocean-current route connecting the bases. The [Ventura County watershed plan](https://vcportal.ventura.org/WCVC/IRWMP/2019/Appendix%20C%20-%20Ventura%20River%20Watershed%20Section.pdf) identifies San Antonio Creek as drainage for the greater Ojai Valley. If a later scope requires that tributary, acquire its own geometry rather than extending this centerline.

The [California Water Board](https://waterboards.ca.gov/losangeles/water_issues/programs/tmdl/docs/R12-011_RB_RSL.pdf) describes intermittent river reaches and a sandbar that can interrupt direct ocean discharge. The map can show hydrographic connection; it cannot imply that the full river currently contains flowing water or that the estuary is presently open. No river velocity, temperature, or ocean transport field was acquired in this geography task.

## Coastline

`coastline.geojson` is ready to draw, clipped to `[-120.15, 32.4, -116.9, 34.57]`. It has two source-labeled MultiLineString features and 3,245 vertices in about 134 kB:

1. US coastline, including the Channel Islands: 1,652 original [USGS NHD coastline features](https://hydro.nationalmap.gov/arcgis/rest/services/nhd/MapServer/6), code 56600. Clipping followed by 200 m Ramer–Douglas–Peucker simplification in a local equirectangular projection reduces 67,710 clipped vertices to 3,237. Original reach endpoints remain. Tiny closed features that collapse below three points at this tolerance are omitted. Coordinate checks confirm all delivered vertices lie inside the requested bounds and that Santa Rosa, Santa Cruz, Anacapa, San Nicolas, Santa Catalina, and San Clemente are represented. Only the eastern portion of Santa Rosa is inside the requested western limit; San Miguel lies outside it.
2. The small Mexican coast south of the US NHD extent uses [Natural Earth 1:10 million coastline](https://www.naturalearthdata.com/downloads/10m-physical-vectors/10m-coastline/), downloaded from the [maintainer's public repository](https://github.com/nvkelso/natural-earth-vector/blob/master/geojson/ne_10m_coastline.geojson). Three clipped parts, eight vertices. The source change at latitude 32.53429556 is preserved without a fabricated joining segment. Natural Earth “10m” denotes 1:10 million scale, not ten-meter resolution.

The [USGS coastline definition](https://www.usgs.gov/ngp-standards-and-specifications/national-hydrography-dataset-nhd-data-dictionary-feature-domains) identifies its NOAA origin and mean-high-water basis, including conceptual closures across inland-water mouths. It is therefore a geographic outline, not the current waterline, a land/water mask for WCOFS cells, or proof of resolved nearshore currents. A separate visible nearshore data gap remains appropriate.

The bundled [coastline-receipt.json](coastline-receipt.json) records counts and the hash of [coastline.geojson](coastline.geojson). Exact source requests are retained in [coastline-nhd-original.geojson.url.txt](coastline-nhd-original.geojson.url.txt) and [natural-earth-10m-coastline-original.geojson.url.txt](natural-earth-10m-coastline-original.geojson.url.txt). Each coastline feature also retains its original-source SHA-256, source URL, and transformation description. The large original coastline datasets, alternate derived outlines, and preprocessing program remain in the authoring workspace and are not part of this public bundle.