MakingTemporalSearchMoreCentralinaSpatialDataInfrastructure
BenjaminLewis,PaoloCorti
20172nd InternationalSymposiumonSpatiotemporalComputing
HarvardUniversity
Thesis
• Timeisanunderutilizeddimensionforimprovingsearchingeosystems.
• Straightforwardmethodsexistwhichcanbetransformativeforresearch.
(BetteruseoftheTemporalisjustoneofseveralwaysinwhichSDIscanbemodernized.)
GeoPlatform SearchUI
GeoNode SearchUI
Systemswehavebeenworkingon
1. WorldMap – Generalpurposepublicmappingplatform.Inexistencesince2012.
2. TheBillionObjectPlatform(BOP)– Prototypetolowerbarrierstoaccesstobigstreamingdatasets.Recentlyreleased.
Differentsystems,commonneedtoimprovesearch
1. WorldMap (ManyDatasets)- Thousandsofdatalayerswithimperfectmetadata.
2. BOP(OneBigDataset)- Abilliongeoreferenced,timestampedtweets.
Listofenhancementstobediscussed
• TimeMinerforunstructuredtextmetadata• SortingBC/ADdates• Timebarfordaterangedefinition• Logarithmictimebarincrements• Dynamictemporalhistogram• Abilitytozoomontemporalhistogram
PythonTimeMinertoenrichmetadata
• Metadataformaplayersisofteninconsistentfortimereferencing.
• Standardwaysofdescribingdate/timesuchasISO8601arerarelyused.
• Temporalcharacteristicsmentionedasunstructuredtextinthetitle,abstract,andelsewhere.
InitialsimpleTimeMiner Logic
1. Lookfordateinthedaterangesectionofthemetadataandchoosetheearlierdate.(Date:fromMetadata)
2. Ifthereisno#1above,lookfor4digitnumbersintitlefirst,thenabstract,whicharelessthanorequalto2017(presentyear)(Date:Detected)
3. IfthereISadatein#2above,checktoseewhetherthereisaCEorADorBCEorBCafteritandapplymathaccordingly(Date:Detected)
4. IfthereISNO#2above,lookfor1,2,or3digitnumberswithassociatedCE,AD,BCE,BC,andapplymathaccordingly(Date:Detected)
Anothertechnique:HistoricPeriodsExample:ChineseDynasties
• Xia, Hsia ca.2100-1600BCE• Shang ca.1600-1050BCE• Zhou,Chou ca.1046-256BCE• Qin,Ch'in 221-206BCE• Han 206BCE-220CE• Sui 581-618CE• Tang,T'ang 618-906• Song,Sung 960-1279• Yuan 1279-1368• Ming 1368-1644• Qing,Ch'ing 1644-1912Source:http://afe.easia.columbia.edu/timelines/china_timeline.htm
WorldMap SearchDemo
• animation
• anim
TemporalHistogram
Conclusion• Mostspatialdatadescribeseventsintime thoughoftennotexplicitly.
• Whendatadoeshaveatimecomponentitisoftennoteasilyaccessed.
• Anopportunityexiststoincreasethevalueofexistingdataby:1. Makinglatenttemporalinformationexplicitusing
enrichmenttechniques2. ImplementingUI/backendenhancementsonexisting
systems3. Increaseresearchonspace/timedataexploration
MoreinformationWorldMap /HHypermap• Information
http://gis.harvard.edu/publications/implementing-open-source-spatiotemporal-search-platform-spatial-data-infrastructures
• Sourcecodehttps://github.com/cga-harvard/HHypermap
BOP• Informationhttp://gis.harvard.edu/services/project-
consultation/project-resume/billion-object-platform-bop• Sourcecodehttps://github.com/cga-harvard/hhypermap-
bop