All the contents in a shapefile can be divided into two categories: Data related Main file record contents Main file header's data description fields (Shape Type, Bounding Box, etc.) File management related File and record lengths Record offsets, and so on The integers and double integer that make up the data description fields in the file header (identified below) and record contents in the main file are in little endian (PC or Intel") byte order. The integers and double precision floating point numbers that make up the rest of the file and file management are in big endian (Sun" or Motorola% byte order. The Main File Header The main file header is 100 bytes long Table 1 shows the fields in the file header with their byte position value, type, and byte order. In the table, position is with respect to the start of the files