Israeli Transverse Mercator

Israeli Transverse Mercator (ITM), also known as the New Israel Grid (NIG; Reshet Yisra'el Ha-Ḥadasha) is the official projected coordinate system for Israel since 1998. It is based on the transverse Mercator map projection, optimized for Israel. ITM has replaced the old Israeli Cassini Soldner (ICS) coordinate system, also known as the Old Israel Grid (OIG).

The need for a new grid ITM replaced the Old Israel Grid (OIG) (), also known as the Israel Cassini Soldner (ICS), which was based on the Cassini-Soldner projection. ICS in turn was a simple modification of the Palestine grid used during the British mandate. The central meridian in the new projection, as in the old one, crosses through Jerusalem. The new grid has two main advantages. One is that the Transverse Mercator projection is better for navigation than Cassini-Soldner. The other is that ICS was based on a 19th-century reference ellipsoid (approximation of the shape of the Earth) and this was replaced by a more accurate approximation.

Additional information on the creation of the new grid is available in Hebrew."New Grid for Israel", in Hebrew, retrieved September 27, 2007, about the New Israeli Grid, published by the Mapping Center of Israel (MAPI) in the official website

Examples

An ITM coordinate is generally given as a pair of six digit numbers (excluding any digits behind a decimal point which may be used in very precise surveying). The first number is always the Easting and the second is the Northing. The easting and northing are in metres from the false origin.

The ITM coordinate for the Western Wall in Jerusalem is 222286 632556, which means

E 222286 m N 631556 m

The first figure is the easting and means that the location is 222,286 meters east from the false origin (along the X axis). The second figure is the northing and puts the location 631,556 meters north of the false origin (along the Y axis). Also notice how the easting in this example is indicated with an “E” and likewise an “N” for the northing.

The table below shows the same coordinate in 3 different grids: Grid Easting Northing PAL (Palestine grid) 172249 1131586 ICS (Israeli Cassini-Soldner) 172249 1131586 ITM (Israeli Transverse Mercator) 222286 631556 UTM (Universal Transverse Mercator) 711563 3518045

Grid Parameters The ITM coordinate system is definedSurvey Regulations 2016, p. 36 (1378) by the following parameters:

Projection

Transverse Mercator

Reference ellipsoid Ellipsoid GRS80 Semi-major axis a 6378137.000 meter Inverse flattening (1/f) 298.257222100882711

Origin Point Latitude 31° 44' 03.8170" NLongitude 35° 12' 16.2610" E

False Origin False Easting 219529.584 meterFalse Northing 626907.390 meterScale Factor 1.0000067

Parameters for conversion to WGS84

Reference ellipsoid Ellipsoid WGS84 a 6378137 meter 1/f 298.257223563

Shift dX -24.0024 meter dY -17.1032 meter dZ -17.8444 meter

Rotation X -0.33077 sec Y -1.85269 sec Z 1.66969 sec

Scale Scale 5.4248 ppm

Israeli Transverse Mercator

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