loranc

A browser-native geodetic Loran-C workspace with a Niijima-centered polar analysis view, live latitude and longitude inspection, and editable TD plotting for the active GRI 8930 chain.

Geodetic solver Polar analysis 100 local slots PNG export

Waypoint

TD entry

Enter the current description and timing differences for the three active secondary stations in the GRI 8930 chain.

GRI 8930

Description30 chars max

W-Gesashi Y-Tokachibuto Z-Pohang (ROK)

Selection

LOP priority

Use the original auto sort or override it with a manual station order like WY or ZYW.

Auto usability sort Manual order

Manual station orderAccepts W, Y, Z Typed length controls how many LOPs are drawn. Missing stations are appended internally for fix confirmation. Automated fix marker Uses the top two prioritized LOPs and checks for a nearby third confirmation LOP.

Waypoints

Saved slots

Slot 01

Empty slot. Save the current TD set to keep it in this browser.

Waypoints are stored in localStorage on this browser only. Use Export PNG to save the current plot image.

Plot window

Niijima-centered geodetic polar analysis view

An azimuthal equidistant display with geodetic LOP solving, adaptive graticules, and an embedded Japan and East Asia raster underlay.

Current description No waypoint selected

Selected slot Slot 01

100%

New map Classic map

Wheel or pinch to zoom. Drag to pan. Hover or tap the plot to inspect latitude, longitude, and predicted TDs.

Plot status

Original GRI8930 base map ready. Enter one or more valid TDs, then press Plot.

Validation

TD values set to 0 are treated as missing and skipped from ranking and plotting.

Fix logic

Automated fix marker uses the top two prioritized LOPs and checks them against the third when enough valid TDs are available.

Active order: Awaiting valid TDs

Geographic inspector

Hover or tap the canvas to inspect cursor coordinates in decimal degrees and DMS.

Predicted TDs for W, Y, and Z will appear here after the map is active.

Plot a valid LOP set to compute a geodetic fix estimate.

Derived order

LOP ranking

Auto usability sort