Equator is commonly modeled as a sphere flattened 0.336% along its axis. This makes the Equator 0.16% longer than a meridian (a great circle passing through the two poles). The IUGG standard meridian is, to the nearest millimetre, , one arc-minute of which is , explaining the SI standardization of the nautical mile as , more than less than the geographical mile. The sea-level surface of the Earth (the geoid) is irregular, so the actual length of the Equator is not so easy to determine. "Aviation Week and Space Technology" on 9 October 1961 reported that measurements using the Transit IV-A
The Equator monument The Equator monument The Equator monument is located on the equator in Pontianak, Indonesia. It marks the division between the northern and southern hemispheres. The monument consists of four iron wood poles, each with a diameter of about 0,30 metre, with frontage bollard height is two pieces as high as 3,05 radian place backside bollard and the signpost dart as high as 4,40 metres. Its location is in "Jalan Khatulistiwa", North Pontianak, about 3 kilometres from the city centre of Pontianak. The equator monument is not on the equator any more. The equator has moved slightly southwards and there is