简介:CyberSpacefirstappearedinthesciencefiction,“Neuromancer”byW.Gibson(1984),thistermwasappliedfordescribingthedesperatevisionofthenearfuture,urbandecay,andneuralimplants.Recently,itisperceivedasawordreferringtoanentirelynewuniverseandthespacevirtuallyexistingwithintheworldwidecomputerInternet. BecauseCyberSpaceisanewworduptonow,thereisnotadefiniteconceptionaboutityet.Butwecanunderstanditasfollows:CyberSpaceisavirtualspacewhosedatainformationisstoredinthecomputerInternet.CreatinganyvirtualspacedependsontheelectronicaldataintheInternet.ThoughitislessthanacoupleofdecadessinceCyberSpacewasbroughtforward,ithadgrownatsucharemarkablespeedthatithadexpandedtothewidestcomputernetintheworld——Internet.Nowitsincrementstillmaintainsatthedoublerate eachyear,anditisexpectedthattheCyberSpacewillbringanewparadigmofnetworksocietyforthenextcentury. CyberSpacehasspecialspatialcharacteristics.Thephysicaldistanceisnotvalidinthisspace,sowemustuseanewapproachtodescribethedistance.Therearethreemethods.Oneisvaliddistancethatisafunctionaldistance,asthedistancearedescribedbytimeorcost.Thesecondisapsychologicaldistance.Namely,itisasubjectivemeasurementthatpeopleapperceivedistanceastheyareawayfromtheobject.Thethirdisaholisticdistancewhereeachchainhasitsunit.Ontheotherhand,mostCyberSpacedonottakeaccountofthegravity.Infact,thebearing,magnitudeortimeconsequenceofthegravitycanbedefinedatrandomandeasilymodified,however,theunitlengthanddirectionofthe3DvectorchangewiththedifferentpositionsinCyberSpace.Inthissense,thescaleorshapeofasinglebuildingandstreetarenotrestrictedbythespatialcondition.Theonlyfactormaintainingthespatialshapeistopologyreplacingtheorigingravity,systemtime,colorsetandspatialdimensionsetupwiththeownpsychologicals
简介:BasedonthedevelopingtendencyofpresentChina'sbasicGIS,thispaperdiscussesthedesigningideaforscalesof1∶10000,1∶50000,1∶250000and1∶1000000pyramidlikemultilayerandmultiresolutionofthebasicGIS.AtechnicallinefortheconstructionofbasicGISofthewholecountryandvariousprovincesforsustainabledevelopmentisputforward.AndsomeimportanttheoreticalGISissuestouchedbythetechnicalprocessarediscussed.