## Blog Post

### The unit of the chart.

* The unit of the chart* is the length of an equatorial mile expressed in millimetres.

The basic element used to build a map in Mercator projection is the unit-of-the-chart. (mai mult…)

### Rhumb line in the Mercator projection

The * Mercator projection* is a plane conformal projection and is not perspective.

This projection is the most often use in navigation. (mai mult…)

### The variation of the chart scale in the Mercator projection

In the Mercator projection, the chart scale varies, increasing proportionally with (sec ϕ) from the Equator to the poles. (mai mult…)

### Difference of Meridional Parts or Meridional Difference.

* The Difference of meridional parts or Meridional difference (Δϕc):* It’s the distance measured on the meridian between two parallels of a Mercator projection. Or, the difference between the meridional parts of any two given parallels. (mai mult…)

### Meridional Parts

* Meridional Parts (or Increased Latitude):* It is the length of the arc of meridian in the Mercator projection, comprised between the Equator and the considered latitude and expressed in minutes of Equator. Noted with (ϕc) or (M). (mai mult…)