Plane Surveying
Plane surveying is a branch of surveying in which the surface of the earth is considered as plane surface. For small projects covering Area less than 250 sq.km. Earth curvature is not counted for in distances.
 The earth surface is considered as plain surface
 The Curvature of the earth is ignored. (i.e., 2 dimensional)
 Survey accuracy is low
 Line joining any two stations is considered to be straight
 The triangle formed by any three points is considered as plain
 Carried out for a small area of <250 km
 Plane surveying uses normal instruments like chain, measuring tape, theodolite etc.
Geodetic Surveying
Geodetic surveying is another branch of surveying in which the curvature of the earth is considered when taking measurements on earth’s surface. When survey extends over a large areas more than 250 sq. km. and degree of accuracy is also great. Geodetic survey is used to provide control points to which small surveys can be connected.
 The earth surface is considered as curved surface
 The Curvature of the earth is taken into account
 Survey accuracy is high
 The line joining any station is considered as spherical
 The triangle formed by any three points is considered as spherical
 Carried out for area of >250 km
 Geodetic surveying uses more precise instruments and modern technology like GPS.
Difference in table format:
PLANE SURVEYING 
GEODETIC SURVEYING 

1  The earth surface is considered as plain surface  The earth surface is considered as curved surface 
2  The Curvature of the earth is ignored  The Curvature of the earth is taken into account 
3  Survey accuracy is low  Survey accuracy is high 
4  Line joining any two stations is considered to be straight  The line joining any station is considered as spherical 
5  The triangle formed by any three points is considered as plain  The triangle formed by any three points is considered as spherical 
6  Carried out for a small area of <250 km  Carried out for area of >250 km 
7  Plane surveying uses normal instruments like chain, measuring tape, theodolite etc.  Geodetic surveying uses more precise instruments and modern technology like GPS. 