GPS之家

RoadMapisanopensource(GPL)programthatprovidesacarnavigationforLinux,UNIXandnowWindowsCE(a.k.a.PocketPC).Itdisplaysamapofthestreets,tracksthepositionprovidedbyaNMEA-compliantGPSreceiver,identifiesthestreetmatchingthisGPSpositionandannouncesthenameofthecrossingstreetatthenextintersection.ArudimentarytripfeatureallowsRoadMaptodisplaysomebasicnavigationinformation(distancetothedestination,direction,speed,etc..).Voicemessagesaregeneratedthatduplicatesomeofthescreeninformation.

Itispossibletodisplayaspecificareabyprovidinga(completeorincomplete)postaladdress,theintersectionoftwostreetsoranexactposition(longitude/latitude).

ThemapfilesusedbyRoadMaparegeneratedfromtheTIGERfilesprovidedbytheUSCensusBureau,andthuscovertheUSAonly.TheRoadMapmapformatisabinaryformatthatissensitivetotheendiannessoftheprocessor.MapsavailableonthissitecoveralltheUSAandhavebeengeneratedforalittleendianprocessor(suchastheIntelPentiumandStrongARMprocessors).

RoadMaphasbeendesignedtobeusableonbothadesktoporlaptopPC,oronaPDAsuchastheiPAQfromHP(formelyfromCOMPAQ).ItcanuseeithertheGtk1.2,Gtk2.0orQTgraphiclibraryforitsuserinterface.TheQtinterfacesupportstheSharp'sZaurusPDA.Allthesemachinessharethesameendiannessandcanusethemapsprovidedonthissite.

RoadMapisatanearlystageofdevelopment.Atthistimetherearenoroutingfeaturesimplementedyet.Theplanforthefutureistoimplementsomenavigationfeaturessimilartothosefoundincommercialstreetnavigationsystems.ThemainlimitforimplementingroutingisthelackofnavigationinformationintheUSCensusBureaudatabase(forexampleone-waystreetarenotindicated).TheUSCensusBureauhasclearlyindicatedthatitdoesnotplantoaddtheseinformationinthefuture(theUSCBdoesnotneedthem).

RoadMapusesgpsdfortheGPSlinkandflite(festivallite)forthevoicemessages.Notethatflitecanberebuiltwithbettervoicesthanthedefaultone(suchasaUSvoiceinsteadofabritishone--somemaydisagree.SeethefliteREADMEformoreinformation.Hereisanexample,courtesyofScotWilcoxon:

  cdflite
  makeclean  #toremoveoldexecutablefiles
  ./configure--with-vox=cmu_us_kal16

RoadMapcomeswithitsownGPSstatusscreen,whichprovidesanoverviewofthesatellitesreceivedandhighlightsthosetheGPShasafixon.ThisstatusscreenallowsforplacingtheGPSdeviceinapositionthatoptimizessatellitereception,evenifthatmeansmakingtheGPSdevice'sscreennotaccessible.

RoadMapusesabinaryfileformatforrepresentingthemapsthatiscompactenoughtoallowthestorageofmanymapsonaCompactFlashorMultiMediacard.Forexample,themapofLosAngelescountytakesabout10Mbytesofflashspace.RoadMapcomeswithasetoftoolstoconverttheUSCensusbureaudata(boththe2000and2002versions)intoitsownmapformat.FutureversionsoftheUSCensusbureaudatawillbesupportedaswell(usuallya1or2monthsafterthedatahasbeenreleased).

WhenRoadMapstarts,itdisplaysamapofthesameareathatwasdisplayedonthelatestsession.Clickingonthemapscreentriggersa"sign"thatdisplaysthenameofthestreet,roadorfreeway(ifany)thatistheclosesttothemousehotpoint.