读取照片属性GPS：Exif信息简介

Exif就是用来记录拍摄图像时的诸多信息：图像信息（厂商，分辨率等），相机拍摄记录（ISO，白平衡，饱和度exif中gps数据的格式，锐度等），缩略图（缩略图宽度，高度等），gps（拍摄时的经度，纬度，高度）等，将这种信息根据JPEG文件标准放在图像文件头部。

Exchangeable Image File(可交换图像文件)的缩写，

最初由日本电子工业发展协会(JEIDA --Japan Electronic Industry Development Association) 制订，目前的最新版本是2.21 版。国际标准化组织(ISO)正在制定的相机文件设计标准（DCF -- Design role for Camera File system）可能以Exif2.1为基础。

Exif 文件实际是JPEG文件的一种，遵从JPEG标准，只是在文件头信息中减少了有关拍摄信息的内容和索引图。所以你可以使用任何支持JPEG格式的图像工具插件观看或设置Exif文件，但开启时也许看不到Exif信息，一旦更改，Exif信息也许丢失。

简单来说，EXIF信息就是由数码相机在拍摄过程中收集一系列的信息，然后把信息放置在我们了解的 JPEG/TIFF 文件的头部，也就是说 EXIF信息是镶嵌在 JPEG/TIFF 图像文件格式内的一组拍摄参数，主要包含摄影时的变焦、快门、ISO、日期时间等诸多与以前摄影条件相关的讯息，相机品牌机型，色彩编码，拍摄时录制的声音或者全球定位系统（GPS）等信息。

简单的说，它就似乎是傻瓜相机的日期打印功能一样，只不过 EXIF信息所记录的资讯更为详尽和完备。

在window平台中可以借助右键查找照片信息中获取较为详细的Exif信息。

要想拿到全部的标准的Exif信息，可以使用其它的硬件，就是CADsee可以，但是没有试过，这里使用一个Exif查看软件Opanda PowerExif，可以非常全面的查看相关的属性。

实例分析：PICT0021.JPG

00 FF D8 FF E1 3A 59 45 78 69 66 00 00 4D 4D 00 2A

10 00 00 00 08 00 0C 01 0E 00 02 00 00 00 0E 00 00

20 03 F4 01 0F 00 02 00 00 00 20 00 00 04 02 01 10

30 00 02 00 00 00 20 00 00 04 22 01 12 00 03 00 00

40 00 01 00 01 00 00 01 1A 00 05 00 00 00 01 00 00

50 04 42 01 1B 00 05 00 00 00 01 00 00 04 4A 01 28

60 00 03 00 00 00 01 00 02 00 00 01 31 00 02 00 00

70 00 20 00 00 04 52 01 32 00 02 00 00 00 14 00 00

80 04 72 02 13 00 03 00 00 00 01 00 01 00 00 87 69

90 00 04 00 00 00 01 00 00 00 9E 88 25 00 04 00 00

A0 00 01 00 00 02 A2 00 00 02 E4 00 28 82 9A 00 05

B0 00 00 00 01 00 00 04 86 82 9D 00 05 00 00 00 01

C0 00 00 04 8E 88 22 00 03 00 00 00 01 00 02 00 00

D0 88 27 00 03 00 00 00 01 00 C8 00 00 90 00 00 07

E0 00 00 00 04 30 32 32 31 90 03 00 02 00 00 00 14

F0 00 00 04 96 90 04 00 02 00 00 00 14 00 00 04 AA

100 91 01 00 07 00 00 00 04 01 02 03 00 91 02 00 05

110 00 00 00 01 00 00 04 BE 92 01 00 0A 00 00 00 01

120 00 00 04 C6 92 02 00 05 00 00 00 01 00 00 04 CE

130 92 04 00 0A 00 00 00 01 00 00 04 D6 92 05 00 05

140 00 00 00 01 00 00 04 DE 92 06 00 05 00 00 00 01

150 00 00 04 E6 92 07 00 03 00 00 00 01 00 02 00 00

160 92 08 00 03 00 00 00 01 00 00 00 00 92 09 00 03

170 00 00 00 01 00 20 00 00 92 0A 00 05 00 00 00 01

180 00 00 04 EE 92 7C 00 07 00 00 00 40 00 00 04 F6

190 A0 00 00 07 00 00 00 04 30 31 30 30 A0 01 00 03

1A0 00 00 00 01 00 01 00 00 A0 02 00 04 00 00 00 01

1B0 00 00 12 00 A0 03 00 04 00 00 00 01 00 00 0D 80

1C0 A0 05 00 04 00 00 00 01 00 00 02 84 A2 15 00 05

1D0 00 00 00 01 00 00 05 36 A2 17 00 03 00 00 00 01

1E0 00 02 00 00 A3 00 00 07 00 00 00 01 03 00 00 00

1F0 A3 01 00 07 00 00 00 01 01 00 00 00 A4 01 00 03

200 00 00 00 01 00 00 00 00 A4 02 00 03 00 00 00 01

210 00 00 00 00 A4 03 00 03 00 00 00 01 00 00 00 00

220 A4 04 00 05 00 00 00 01 00 00 05 3E A4 05 00 03

230 00 00 00 01 00 29 00 00 A4 06 00 03 00 00 00 01

240 00 00 00 00 A4 07 00 03 00 00 00 01 00 00 00 00

250 A4 08 00 03 00 00 00 01 00 00 00 00 A4 09 00 03

260 00 00 00 01 00 00 00 00 A4 0A 00 03 00 00 00 01

270 00 00 00 00 A4 0B 00 07 00 00 00 04 00 00 00 00

280 A4 0C 00 03 00 00 00 01 00 00 00 00 00 00 00 00

290 00 02 00 01 00 02 00 00 00 04 52 39 38 00 00 02

2A0 00 07 00 00 00 04 30 31 30 30 00 00 00 00 00 05

2B0 00 00 00 01 00 00 00 04 02 02 00 00 00 01 00 02

2C0 00 00 00 02 4E 00 00 00 00 02 00 05 00 00 00 03

2D0 00 00 05 46 00 03 00 02 00 00 00 02 45 00 00 00

2E0 00 04 00 05 00 00 00 03 00 00 05 5E 00 00 00 00

2F0 00 06 01 03 00 03 00 00 00 01 00 06 00 00 01 1A

300 00 05 00 00 00 01 00 00 05 76 01 1B 00 05 00 00

310 00 01 00 00 05 7E 01 28 00 03 00 00 00 01 00 02

320 00 00 02 01 00 04 00 00 00 01 00 00 07 F4 02 02

330 00 04 00 00 00 01 00 00 32 5D 00 00 00 00 00 00

FF D8 SOI

FF E1 APP1

3A 59 APP1 LENGTH

45 78 69 66 00 00 Exif ASCII结束符两个

4D 4D MM big endian TIFF Header (注意小端的为：49492A00 08000000)

00 2A fixed

00 00 00 08 IFD0 offset

00 0C IFD0: number of TAGs 12个tag，每个12字节。

01 0E TAG Image title

00 02 TYPE ASCII

00 00 00 0E count 最多13个字符

00 00 03 F4 offset +0C=0x400 可以看到DCIM\100MEDIA (0x0c from the start of the TIFF header 4D4D MM)

01 0F TAG Image input equipment manuf

00 02 TYPE ASCII

00 00 00 20 count 最多31个字符

00 00 04 02 offset +0c=0x040E 可以看到TCL

01 10 TAG Image input equipment model

00 02 TYPE ASCII

00 00 00 20 count

00 00 04 22 offset +0c=0x042E 可以看到SDV05

01 12 TAG Orientation of image

00 03 SHORT 00 01

00 00 00 01 count

00 01 00 00 value

01 1A TAG Image resolution in width 0x0442+0c=0x44E，可以看到00 00 00 48/00 00 00 01

00 05 RATIONAL

00 00 00 01 count

00 00 04 42 offset +0c=0x44E，可以看到00 00 00 48/00 00 00 01

01 1B TAG Image resolution in height

00 05 RATIONAL

00 00 00 01

00 00 04 4A offset+0c=0x456 可以看到00 00 00 48/00 00 00 01

01 28 Unit of X and Y resolution

00 03 SHORT 00 02

00 00 00 01

00 02 00 00

01 31 Software used

00 02 ASCII

00 00 00 20 count

00 00 04 52 offset +0c =0x45E 可以看到0.0.2

01 32 DateTime

00 02 ASCII

00 00 00 14 20字节

00 00 04 72 offset+0c=0x47E，可以看到2012:07:29 21:28:18

02 13 YCbCrPositioning

00 03 SHORT 00 01

00 00 00 01

00 01 00 00

87 69 Exif IFD Pointer

00 04 LONG

00 00 00 01 count

00 00 00 9E offset+0c=0xAA

88 25 GPS Info IFD Pointer

00 04 LONG

00 00 00 01 count

00 00 02 A2 offset+0c=0x02AE

00 00 02 E4 nextIFD IFD1 offset

00 28 Exif IFD number of TAGs

82 9A ExposureTime

00 05 RATIONAL

00 00 00 01 count

00 00 04 86 offset+0c=0x0492

...

Exif的相关信息这里先不做分析exif中gps数据的格式，请你们参照下面的文档自己预测了。

这里主要是预测GPS相关信息

GPS Info IFD Pointer 0x02AE 从里面数据2A0行的前面看数据

00 05 count of TAGs

00 00 GPSVersionID

00 01 BYTE

00 00 00 04 count

02 02 00 00 value 2.2.0.0

00 01 GPSLatitudeRef

00 02 ASCII

00 00 00 02 count

4E 00 00 00 N North

00 02 GPSLatitude

00 05 RATIONAL 前4字节为分子，后4字节为乘数，十六进制先转为十进制

00 00 00 03 count

00 00 05 46 offset+0c=0x552 16 00 00 00 01 00 00 00 22 00 00 00 01 00 00 00 51 00 00 00 04 00 00 00

22/1=22 34/1=34 81/4= 20.25

通过windows的单击属性看具体信息：22；34；20.249999999999915

00 03 GPSLongitudeRef

00 02

00 00 00 02 count

45 00 00 00 East

00 04 GPSLongitude

00 05 RATIONAL

00 00 00 03 count

00 00 05 5E offset+0c=0x56A 71 00 00 00 01 00 00 00 37 00 00 00 01 00 00 00 6C 00 00 00 04 00

113/1=113 55/1=55 108/4=27

通过windows的单击属性看具体信息：113;55;27.000000000000171

550 04 00 16 00 00 00 01 00 00 00 22 00 00 00 01 00

560 00 00 51 00 00 00 04 00 00 00 71 00 00 00 01 00

570 00 00 37 00 00 00 01 00 00 00 6C 00 00 00 04 00

580 00 00 00 00 00 48 00 00 00 01 00 00 00 48 00 00

590 00 01 00 00 00 00 00 00

本文来自电脑杂谈，转载请注明本文网址：
http://www.pc-fly.com/a/ruanjian/article-128380-1.html