Gravity of Earth Gravity acceleration is a vector quantity. In a spherically symmetric Earth, gravity would point directly towards the sphere's centre. As the Earth is slightly flatter, there are consequently slight deviations in the direction of gravity. Tools exist for calculating the strength of gravity at various cities around the world. The effect of latitude can be clearly seen with gravity in high-latitude cities: Anchorage (9.826 m/s), Helsinki (9.825 m/s), being about 0.5% greater than that in cities near the equator: Kuala Lumpur (9.776 m/s), Manila (9.780 m/s). The effect of altitude can be seen in Mexico City (9.776 m/s; altitude ),
Circle of latitude projections, the circles of latitude are neither straight nor parallel. Arcs of circles of latitude are sometimes used as boundaries between countries or regions where distinctive natural borders are lacking (such as in deserts), or when an artificial border is drawn as a "line on a map", which was made in massive scale during the 1884 Berlin Conference, regarding huge parts of the African continent. North American nations and states have also mostly been created by straight lines, which are often parts of circles of latitudes. For instance, the northern border of Colorado is at 41°N while the southern border