The British Mandate Palestine grid (Arabic: التربيع الفلسطيني) was the geographic coordinate system used by the Survey Department of Palestine. The system was chosen by the Survey Department of the Government of Palestine in 1922. The projection used was the Cassini-Soldner projection. The central meridian (the line of longitude along which there is no local distortion) was chosen as that passing through a marker on the hill of Mar Elias Monastery south of Jerusalem. The false origin (zero point) of the grid was placed 100 km to the south and west of the Ali el-Muntar hill that overlooks Gaza city. The unit length for the grid was the kilometre; the British units were not even considered.