1. Geographic coordinates are a standardized method to describe any position on the earth's surface. It is a method of expressing geographical position by latitude and longitude, which enables people to accurately determine the position of any point on the earth. Geographical coordinate system is widely used in map making, navigation, astronomy, meteorology, geology and other fields.
2. The basic unit of geographical coordinates is degree (), which can be divided into 60 points (') at one time. Longitude refers to the angle between the ray extending from a certain point on the earth to the east-west direction and the prime meridian, ranging from-180 to+180.
3. Latitude refers to the included angle between the equator and a point on the earth extending in the north-south direction, ranging from-90 to+90. Longitude and latitude are expressed by east longitude (E) and west longitude (W), north latitude (N) and south latitude (S) respectively.
4. The representation method of geographical coordinates is: in the plane rectangular coordinate system, the prime meridian is taken as the benchmark, and the east is positive and the west is negative; Based on the equator, it is positive to the north and negative to the south. For example, new york is located at 40.7 128 north latitude and 74.0060 west longitude, which can be expressed as 40.7 128 north latitude and 74.0060 west longitude.
5. There are many kinds of geographic coordinate systems, among which UTM (Universal Transverse Axis) coordinate system and Lambert projection coordinate system are the most commonly used. UTM coordinate system is a coordinate system based on mathematical rules, which divides the earth's surface into 60 belt-shaped regions, and each region has a unique number.
6.UTM coordinate system has the advantages of high spatial resolution and good mathematical properties, and is suitable for large-scale geographic data processing. Lambert projection coordinate system is an equal area projection method, which converts the latitude and longitude coordinates of the earth's surface into plane rectangular coordinates. This projection method is suitable for small-scale map making and navigation applications.