State Plane Zone Lookup — Tool Guide

Coming Soon NAD83 STATE PLANE · NGS · ALL GUIDES

The State Plane Zone Lookup identifies the U.S. State Plane Coordinate System (SPCS83) zone for any location — by FAA airport identifier, by state, or by latitude/longitude — and serves as the basis for transforming coordinates between geographic lat/lon and State Plane northing/easting. Zones are drawn from the EPSG/NGS registry under the NAD83 datum, and the coordinate transforms are computed server-side with pyproj, so the result is the same projection a surveyor or CAD platform would apply.

It replaces the manual step of cross-referencing a county against a State Plane zone index, then hand-keying the right projection definition into CAD — the workflow behind nearly every Exhibit 'A' property map and airport survey deliverable that reports grid coordinates.

Open the State Plane tool →

Who It's For & When to Use It

Airport planners and survey-coordination staff who need the correct State Plane zone for a facility before producing grid-coordinate deliverables — Exhibit 'A' property inventory maps, ALP base mapping, and airport survey narratives that report northing/easting. Use it when you have an airport identifier or a pair of coordinates and need the governing SPCS83 zone, when confirming which zone a project site falls in before setting up a CAD coordinate system, or when a project spans a state line or zone boundary and you need to see every applicable zone at once.

How to Use It

  1. Choose how to find the zone. Three tabs cover the common cases: By Airport (enter a FAA LID or ICAO identifier), By State (pick a state or territory to see its zones), or By Coordinates (enter a latitude and longitude). Pick the one that matches what you have on hand.
  2. Look up by airport identifier. On the By Airport tab, type a 3–5 character FAA LID or ICAO code — e.g. KMCO — and select Look Up Zone. The tool fetches the airport's reference point from FAA NASR, shows the data-source chip and NASR cycle, and detects the State Plane zone from those coordinates. When an airport falls back to OurAirports, a continue/stop banner appears before any non-authoritative zone is detected.
  3. Detect the zone from coordinates. On the By Coordinates tab, enter latitude and longitude in decimal degrees or switch to DMS (negative longitude is West) and select Detect Zone. The tool returns the SPCS83 zone that contains the point.
  4. Read the zone code and name. The result card names the SPCS83 zone, its code, and the EPSG/NGS definition behind it. From the By State tab you can expand each zone to read its identifier and coverage description.
  5. Transform the coordinates. The detected zone is the basis for converting between geographic lat/lon and State Plane northing/easting, computed server-side with pyproj. Large northings — above 800,000 ft — are valid and do not trigger a range warning.
  6. Copy or share. Copy the zone and coordinates to the clipboard, or carry the detected zone into the Runway Linework workspace. The URL updates as you work (?id= on the airport tab, ?lat=&lon= on the coordinates tab) with history.replaceState, so the address bar is always a shareable link that restores the lookup.
  7. Browse zones by state. The By State tab lists every SPCS83 zone for the selected state or territory, with EPSG codes and coverage notes — useful when a project spans more than one zone.

Key Features

  • Three lookup paths. By Airport, By State, and By Coordinates — whichever input you have, the tool resolves the same SPCS83 zone, and the airport path pulls the reference point straight from FAA NASR.
  • Authoritative source surfacing. The By Airport tab carries the shared Airport Identity Bar: a data-source chip, the NASR cycle date, and the mandatory OurAirports continue/stop fallback banner — the tool never silently detects a zone from non-authoritative coordinates.
  • Decimal-degree or DMS entry. Coordinate input accepts decimal degrees or degrees/minutes/seconds with a hemisphere selector, so you can key coordinates in whatever form your source provides.
  • Coordinate transforms via pyproj. Geographic ↔ State Plane conversions are computed server-side with pyproj against the zone's NAD83 definition — large northings above 800,000 ft are valid, with no spurious range warning.
  • Handoff to the runway workspace. A detected zone can be carried into the Runway Linework Generator (?zone=) so linework lands in the right projection.
  • Shareable URLs and deep-links. Lookups mirror into the query string with history.replaceState; inbound ?id= and ?lat=&lon= deep-links restore the exact lookup.

FAA References

  • NGS State Plane Coordinate System of 1983 (SPCS83) — the geodetic basis for every zone returned; zone definitions follow the EPSG registry of the NAD83 SPCS83 zones maintained by the National Geodetic Survey.
  • NAD83 (North American Datum of 1983) — the horizontal datum underlying SPCS83; all coordinate transforms are referenced to it.
  • FAA airport surveys and Exhibit 'A' property inventory maps commonly report grid coordinates in the applicable State Plane zone — see ARP SOP 3.00 (Exhibit 'A') and AC 150/5300-18 (general airport survey standards) for where State Plane coordinates appear in airport deliverables.

Limitations & Disclaimers

AvPlot is technical planning production support — accurate enough for design reports, planning studies, and ALP narratives. It is not a replacement for stamped engineering or construction documents. As the tool itself states: zone boundaries are approximate centroids derived from EPSG registry data, and you should always verify the applicable zone against your survey datum and jurisdiction before use in official submittals.

  • Coordinate transforms use pyproj against the NAD83 SPCS83 zone definitions; results match the projection but should be confirmed against your project's control before being treated as survey-grade.
  • State Plane northing above 800,000 ft is valid — the tool does not flag large northings as out of range.
  • SPCS83 covers U.S. locations only; coordinates outside that coverage will not resolve to a zone.

Related Tools

  • ARP Centroid Calculator — compute a proposed Airport Reference Point from runway coordinates, then resolve its State Plane zone here (guide).
  • ARP Lookup — pull the official FAA Airport Reference Point for a facility to feed the By Coordinates lookup (guide).
  • Unit Converter — convert distances and coordinate values between units alongside a State Plane transform (guide).
  • Exhibit 'A' Property Map — parcel inventory and Appendix B checklist that reports grid coordinates in the applicable zone (guide).

Tips & Best Practices

  • Start from the airport identifier when you have one — it pulls the reference point from FAA NASR and shows the cycle date, so the zone is anchored to an authoritative coordinate rather than a hand-typed one.
  • Watch the data-source chip on the By Airport tab: if the OurAirports continue/stop banner appears, the coordinate is non-authoritative — verify it before relying on the detected zone.
  • For projects that straddle a zone boundary, use the By State tab to see every applicable zone before committing the CAD coordinate system — mixing zones across one deliverable is a common rework cause.
  • Don't treat a northing above 800,000 ft as an error — it is valid State Plane and the tool will not warn on it.
  • Copy the URL into your project notes; the ?id= or ?lat=&lon= link documents the exact lookup behind the zone you cited.