ESRI Shapefile 文件格式(2)

Reorder Headers (8 bytes long)

Position	Field	Value	Type	Byte Order
Byte 0	Record Number	Record Number	Integer	Big
Byte 4	Content Length	Content Length	Integer	Big

Record Contents

Its record contents consist of a shape type followed by the geometric data for the shape.(它的标记内容是由包含几何数据的shape类型构成)For each shape types, we first describe the shape ad then its mapping to record contents on disk.

术语解释：

Null Shapes:

A shape type of 0 indicates a null shape, with no geometric data for the shape.也就是没有属性的数据，通常是用来创建shapefile时并且马上就要赋值时的过渡对象

Null Shape Record Contents

Position	Field	Value	Type	Number	Byte Order
Byte 0	Shape Type	0	Integer	1	Little

X.,Y Space

Point

{

Double X

Double Y

}

Position	Field	Value	Type	Number	Byte Order
Byte 0	Shape Type	1	Integer	1	Little
Byte 4	X	X	Double	1	Little
Byte 12	Y	Y	Double	1	Little

MultiPoint

MultiPoint

{

Double[4]

Integer

Point[NumPoints]

}

Position	Field	Value	Type	Number	Byte Order
Byte 0	Shape Type	8	Integer	1	Little
Byte 4	Box	Box	Double	4	Little
Byte 36	NumPoints	NumPoints	Integer	1	Little
Byte 40	Points	Points	Point	NumPoints	Little

PolyLine

{

Double[4] Box

Integer NumParts The number of parts in the PolyLine.

Integer NumPoints The total number of points for all parts.

Integer[NumParts] Parts

An array of length NumParts. Stores, for each PolyLine, the index of its

first point in the points array. Array indexes are with respect to 0.

Point[NumPoints] Points

An array of length NumPoints. The points for each part in the PolyLine are stored end to end.

}

Polygon

{

Double[4] Box

Integer NumParts

Integer NumPoints

Integer[NumParts] Parts (多个闭合环)

An array of length NumParts. Stores, for each ring, the index of its first point in the points array. Array indexes are with respect to 0.

Point[NumPoints] Points

}

1、环必须是闭合的

2、环中各点的次序是不重要的

3、环的任何一条边只能类属于一个环

Organization of te Index File

File Header(100-byte)

Record (8-byte, fixed-length)

Record (8-byte, fixed-length)

Record (8-byte, fixed-length)

`````` (8-byte, fixed-length)

Record (8-byte, fixed-length)

Index Records:
The I'th record I the index file stores the offset and content length for the I'th record in the main file. (16b - words)

Position	Field	Value	Type	Byte Order
Byte 0	Offset	Offset	Integer	Big
Byte 4	Content length	Content Length	Integer	Big

Organization of the dBASE File :

1、The table must contain one record per shape feature

2、The record order must be the same as the order of shape features in the main 3、(*.shp) file.

The year value in the dBASE header must be the year since 190