Geodetic::Coordinate::StatePlane¶

US State Plane Coordinate System¶

The State Plane Coordinate System (SPCS) is a set of 124 geographic zones used across the United States. Each zone uses either a Lambert Conformal Conic or Transverse Mercator projection, chosen to minimize distortion within that zone. Units are typically expressed in US Survey Feet.

Constructor¶

point = Geodetic::Coordinate::StatePlane.new(
  easting:   0.0,
  northing:  0.0,
  zone_code: 'CA_I',
  datum:     Geodetic::Datum::WGS84
)

easting — Easting coordinate (typically in US Survey Feet)
northing — Northing coordinate (typically in US Survey Feet)
zone_code — Identifier for the State Plane zone
datum — The geodetic datum; stored internally on the coordinate object

Available Zones¶

The following zone codes are currently supported:

Zone Code	State / Region
`CA_I`	California, Zone I
`CA_II`	California, Zone II
`TX_NORTH`	Texas, North
`FL_EAST`	Florida, East
`NY_LONG_ISLAND`	New York, Long Island

Projections¶

Each zone uses one of two map projections depending on its geographic shape:

Lambert Conformal Conic — Used for zones that are wider east-to-west
Transverse Mercator — Used for zones that are longer north-to-south

Unit Conversion¶

meters_point    = point.to_meters
feet_point      = point.to_us_survey_feet

Methods¶

Method	Description
`zone_info`	Returns metadata about the current zone (projection type, parameters, bounds)
`valid?`	Returns `true` if the coordinates fall within the defined zone bounds
`zones_for_state(state)`	Class method. Returns available zone codes for a given US state
`find_zone_for_lla(lla)`	Class method. Determines the appropriate State Plane zone for a given LLA coordinate

Datum¶

The StatePlane coordinate object stores its associated datum internally, accessible for reference during conversions and transformations.