Exploring Options for MapExploringOptionsforMapCaching

TileCacheCreation&ManagementPresentedBy:yToddWascher,BusinessDevelopmentManager

04.21.2011

We Visualize Your World

Whachutalkinbout?

Whatwellcoverwiththissession:

A O i AnOverview

CachingExplained(briefly)

General Benefits of Map Caching GeneralBenefitsofMapCaching

SomeCachingTermsandConcepts

A Comparison of Available ToolsAComparisonofAvailableTools

Mapproxy,Tilecache,GeoWebCache,ArcGISServer

Functionality&CapabilitiesofEachy p

Summary&Conclusion

ChoosingtheRightToolfortheJob

ConsumingandUtilizingCachedMapservices

CachingOverviewWell,whatismapcaching?

What types of things can I cache?WhattypesofthingscanIcache?

GotanyExamples?

http://mt0.google.com/vt/lyrs=t@126,r@145&hl=en&x=2018&y=2949&z=13&s=Gal

http://ecn.t2.tiles.virtualearth.net/tiles/r0213331100212?g=637&mkt=en-us&lbl=l1&stl=h&shading=hill&n=z

http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer/tile/13/2949/2018

CachingOverview

What are some benefits of having a cached mapservice?Whataresomebenefitsofhavingacachedmapservice?

LightenBrowserloadh l dLightenServerload

RequestsforsmallimagesratherthandynamicdatarenderingPotentialtoimproveperformance

CachingTerms&Concepts

SeedingSeeding

Metatiling

Tiling SchemesTilingSchemes

ImageTypes

Transparency

Projections/Reprojection

CachingTerms&Concepts

SeedingSeeding

Seeding is basically prerendering or dynamically creating map tiles basedSeedingisbasicallypre renderingordynamicallycreatingmaptilesbaseduponadefinedextentorageometry.

Seedingactionscanbescripted,generatedonthefly(userrequests)ormanuallycreated.

CachingTerms&ConceptsMetatiling

Ametatileconsistsofseveraltilescombinedintoonelargertile.

Pros:

Avoidduplicatingthelabelingoffeaturesthatspanmore than one tilemorethanonetile

UsuallyquickerfortheWMSbackendtogenerateonelargeimageratherthanmanysmallones

Cons:

Sincethemetatileislarger,itisslowertorenderthananyindividualtile

Memoryconsumption

CachingTerms&Concepts

Tiling SchemesTilingSchemes

Tiling schemes allow for definition of scale levels, tile size and sometimesTilingschemesallowfordefinitionofscalelevels,tilesizeandsometimescoordinatesystem.

SettingtilingschemesforArcGISServervarygreaterthantheotheroptions we will reviewoptionswewillreview.

CachingTerms&Concepts

Image TypesImageTypes

Cachedmaptilescanbecreated/requestedindifferentimageformats.Mostcommonly.pngfortransparencyand.jpegforimagery.

Transparency

Transparencyisusedforoverlayingtilesontopofothertilesandforsliding/transitioning effects Supported with pngsliding/transitioningeffects.Supportedwith.png.

AlsoparameterinWMSrequest.

Projections / ReprojectionProjections/Reprojection

Mostcachesarecreatedinadefinedprojection,butsomeutilitiescanreprojecttiles(mapproxy).

How?

Consuming WMS and chopping it up into tilesConsumingWMSandchoppingitupintotiles

Storedinaccessibledirectorytobereturnedtoclient

Application requests handled by cache utilityApplicationrequestshandledbycacheutility

Projection

Location

Tilesize

Imageformat

ComparisonofCachingUtilities

MapProxy

MapProxyisanopensourceproxyforgeospatialdata.Itcaches,acceleratesandtransforms data from existing map services and serves any desktop or web GIStransformsdatafromexistingmapservicesandservesanydesktoporwebGISclient.

MapProxyworkslikeasimpletilecache,butalsooffersmanynewandinnovativefeatureslikefullsupportforWMSclients.

MapProxyisanopensourcetechnologyusedtocreateandserveupmapcaches.Itis a middleman between existing web map servers (like MapServer or GeoServer)isamiddle manbetweenexistingwebmapservers(likeMapServerorGeoServer)andwebmapclientssuchasOpenLayersandGoogleEarth.

TileCache

TileCacheisanimplementationofaWMSCcompliantservermadeavailableundertheBSD(Berkeley Software Distribution) licensebyMetaCarta.

TileCacheprovidesaPythonbasedWMSC/TMSserver,withpluggablecachingmechanisms and rendering backends In the simplest use case TileCache requiresmechanismsandrenderingbackends.Inthesimplestusecase,TileCacherequiresonlywriteaccesstoadisk,theabilitytorunPythonCGIscripts,andaWMSyouwanttobecached.Withtheseresources,youcancreateyourownlocaldiskbasedcacheofanyWMSserver,andusetheresultinanyWMSCsupportingclient,likeOpenLayers,oranyTMSsupportingclient,likeOpenLayersandworldKit.

GeoWebCache

GeoWebCache is a Java web application used to cache map tiles coming from a variety of sources such as OGC Web Map Service (WMS) coming from a variety of sources such as OGC Web Map Service (WMS). It implements various service interfaces (such as WMS-C, WMTS, TMS, Google Maps KML, Virtual Earth) in order to accelerate and optimize map image delivery. It can also recombine tiles to work with regular WMS clients.

http://geowebcache.org/

AMatrix

So,ArcGISServeralreadyhasCachingTools

Singlemapservicefocus

GUI/Geoprocessingoptions

l d fTailoredforesriAPIs

CompactCache

ChoosetheRightToolfortheJob

All caching utilities are basically reading a mapservice taking a snapshot of it andAllcachingutilitiesarebasicallyreadingamapservice,takingasnapshotofitandcuttingitupintotilesdefinedbytheuser/tool.Oncethetilesarecreated,theyarestoredinadirectorystructuresimilarto:

CachedirectoryNameofserviceScalelevelsRowRowColumnImage

Thi h li h l b d h l i d i h j b b i ll ilThismaychangeslightlybasedonwhattoolisdoingthejob,buttypicallytilesareslicedandstoredaroundthegridbasedsystemoflevel,row,column.

UtilizingCachedServices

Web Applications

ArcGIS Desktop

Geoportals/Opendata

ResourcesLinks!

http://mappro org/http://mapproxy.org/

http://tilecache.org/

http://geowebcache.org/

http://help.arcgis.com/en/arcgisserver/10.0/help/arcgis_server_dotnet_help/index html#/What is map caching/00930000006m000000//index.html#/What_is_map_caching/00930000006m000000/

Thanks!Thanks!Feelfreetoaskanyquestionsorshare

yourowntips.y p

17158744397

1888WeDoGIS

Todd.Wascher@adc4gis.com