來源: Android模擬GPS數據生成kml和nmea文件 - 開發者在線 - www.builder.com.cn

在Android平台上開發可能沒有真機的時候,我們通過DDMS中載入KML或NMEA文件來模擬生產數據,使用方法參考 新版ADT插件讓Android開發更人性化 一文,最終這兩個文件加載到/data/misc/location/gps/nmea或/data/misc/location/gps/kml/

  一、KML文件其實是一個XML文件,我們看下KML文件結構

  <?xml version="1.0" encoding="UTF-8"?>

  <kml xmlns="http://earth.google.com/kml/2.2">

  <Document>

  <name>1065 Brea Mall, Brea, CA 92821.kml</name>

  <StyleMap id="default_copy0+nicon=http://maps.google.com/mapfiles/kml/pal3/icon60.png+hicon=http://maps.google.com/mapfiles/kml/pal3/icon52.png">

  <Pair>

  <key>normal</key>

  <styleUrl>#default_copy0+icon=http://maps.google.com/mapfiles/kml/pal3/icon60.png</styleUrl>

  </Pair>

  <Pair>

  <key>highlight</key>

  <styleUrl>#default_copy0+icon=http://maps.google.com/mapfiles/kml/pal3/icon52.png</styleUrl>

  </Pair>

  </StyleMap>

  <Style id="default_copy0+icon=http://maps.google.com/mapfiles/kml/pal3/icon52.png">

  <IconStyle>

  <scale>1.1</scale>

  <Icon>

  <href>http://maps.google.com/mapfiles/kml/pal3/icon52.png</href>

  </Icon>

  </IconStyle>

  <LabelStyle>

  <scale>1.1</scale>

  </LabelStyle>

  </Style>

  <Style id="default_copy0+icon=http://maps.google.com/mapfiles/kml/pal3/icon60.png">

  <IconStyle>

  <Icon>

  <href>http://maps.google.com/mapfiles/kml/pal3/icon60.png</href>

  </Icon>

  </IconStyle>

  </Style>

  <Placemark>

  <name>1065 Brea Mall, Brea, CA 92821</name>

  <address>1065 Brea Mall, Brea, CA 92821</address>

  <LookAt>

  <longitude>-117.883593</longitude>

  <latitude>33.916991</latitude>

  <altitude>0</altitude>

  <range>1000</range>

  <tilt>0</tilt>

  <heading>0</heading>

  </LookAt>

   <styleUrl>#default_copy0+nicon=http://maps.google.com/mapfiles/kml/pal3/icon60.png+hicon=http://maps.google.com/mapfiles/kml/pal3/icon52.png</styleUrl>

  <Point>

  <coordinates>-117.883593,33.916991,0</coordinates>

  </Point>

  </Placemark>

  </Document>

  </kml>

  二、NMEA協議就是常規的GPS數據,通過串口直接獲取到的,如下

  $GPRMC,003347.000,A,3725.3433,N,12205.7920,W,0.08,149.46,061007,,,D*70

  $GPRMC,003348.000,A,3725.3433,N,12205.7921,W,0.05,142.51,061007,,,D*7E

  $GPRMC,003349.000,A,3725.3432,N,12205.7921,W,0.08,159.56,061007,,,D*7E

  $GPRMC,003350.000,A,3725.3432,N,12205.7921,W,0.06,151.59,061007,,,D*7F

  $GPRMC,003351.000,A,3725.3432,N,12205.7921,W,0.20,120.57,061007,,,D*72

  實例:

  解析方法:

  RMC = Recommended Minimum Specific GPS/TRANSIT Data

  $GPRMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,ddmmyy,x.x,a*hh

  1 = UTC(universal time, coordinated) of position fix

  2 = Data status (A=good, V=navigation receiver warning)

  3 = Current Latitude

  4 = North/South in Latitude Hemisphere

  5 = Current Longitude

  6 = East/West in Longitude Hemisphere

  7 = Speed over ground in knots

  8 = (Direction of travel N:0°, E:90°, S:180°, W:270°)

  9 = UT DateStamp

  10 = Magnetic variation degrees (Easterly var. subtracts from true course)

  11 = East/West

  12 = Checksum

  $GPRMC,003347.000,A,3725.3433,N,12205.7920,W,0.08,149.46,061007,,,D*70

  Parts:

  1: 003347.000 --> 0:33 am 47 seconds 0 milliseconds (UTC(universal time, coordinated) of position fix)

  2: A --> Status is ok (Data status (A=good, V=navigation receiver warning))

  3: 3725.3433 (North/South in Latitude Hemisphere)

  4: N --> North (North/South)

  5: 12205.7920 (Current Longitude)

  6: W --> West (East/West in Longitude Hemisphere)

  7: 0.08 --> 0.08 knots/second (Direction: North/West) (Speed over ground in knots)

  8: 149.46 --> sth. like SouthEast (Direction of travel N:0°, E:90°, S:180°, W:270°)

  9: 061007 --> 6th October, 2007 (UT(universal time) DateStamp)

  10: <empty> (Magnetic variation degrees (Easterly var. subtracts from true course))

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