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Landgate and ERDASImage Serving Update

Enabling Local Government

August 2010

Chris TweedieEnterprise SolutionsAustralia / New Zealand

Overview• Landgate has been using ERDAS Apollo IWS since 2000

• Skyview System (2000 – 2007)• MyLandgate Mapviewer (2004 – current)• SLIP Imagery WMS (2007 – current)• VALSYS (current)• Property Finder (2008 – current)• Property Finder Image Extraction (2008 – current)

• Current Imagery archive• 2,500 ECW files totalling 6.5 TB• Largest single image, 70gb Metro South 2010 ECW, 420,000 x 630,000 pixels

• ERDAS continues to push the image serving envelope for performance, scalability, compression and open standards technology.

But Chris…• However, together with Landgate we realise there has

been issues, particularly over last 6 months• SLIP imagery “slow” or unavailable• Mapviewer imagery “slow” to stream• “What’s these stupid white bits…”

• ERDAS diagnosed stability and performance problems in Q1/Q2 this year

• Made 20+ sweeping recommendations• 10 minor issues already implemented and resolved• Landgate will implement the most significant changes on September 1

with full hardware and software upgrade. Yes, that’s next week!

So what does that mean to me?• Software upgrade to Apollo IWS

• 4x Performance improvement• Hardware upgrade to Apollo IWS

• 6x Performance improvement• Extensive testing has shown a 10x throughput gain

across the board• Tests went up to 240 concurrent users

• 1,250.58 maps / sec (256px tiles)• 24 MB / sec throughput• Latest, largest 2010 Metro Mosaic (75gb compressed)

Overall,• Performance limited by network only• NBN is therefore, a good idea

ECW Transparency• Transparency, opacity, null areas, white space … has been a big

customer satisfaction issue for ECW and therefore SLIP• This has been resolved since August last year but requires

reprocessing of existing datasets by customers• As soon as Landgate updates mosaics, null areas will be gone

forever

ESRI ArcGIS Desktop performance• Performance of SLIP Imagery services

• ESRI ArcGIS has the unfortunate limitation of forcing image/png on allWMS requests

• For vector based services this is fine; for imagery this causes large responses which takes longer to serve and to download

• All image/png responses from SLIP Imagery are now 8-bit instead of 24-bit– 3x smaller, faster to download and display

• However the problem still lies with ESRI– JPEG responses 4x faster than even 8bit PNG– ArcGIS is the only client that doesn’t allow users to change the output format- They’ve know for years but remains unsolved

• ERDAS has done as much as we can– Consider using alternative CarbonArc toolbar

Why ECW? Why not JP2? Why not..• ECW is,

• The most optimised raster compression format available– Typically 1:15 ratio gives visually lossless results

• The most optimised raster decompression format available– Uses less I/O, less CPU to decode and generate an image

• Designed for one purpose only, geographic-sized raster storage– Mathematically lossy, 8-bit data only

• Technology patented and owned by ERDAS Inc.– Originally designed and continually developed by the local ERDAS Perth office

• JPEG2000 is,• The ISO open standard format

– Also uses advanced wavelet compression to achieve similar ratio’s• A lot broader in scope

– Not just our industry but movies, medical imaging etc. Many encoding profiles• More computationally expensive• Can be encoded as lossy or lossless, up to 28-bit per pixel

• TIFF is,• The defacto storage format• Limited compression options, typically 1:3 with JPEG compression• For geographic sized images, tiles or overviews are required

– BigTIFF / BigGeoTIFF support required for images > 2gb– Adds 30%+ overhead to original data– Often requires splitting into multiple files for performance reasons.

• Extremely I/O intensive to generate the same image output

Real world comparisons• Customer image converted to ECW, JP2

• 215mb• 66,530 x 20,580 px• Both compressed to 1:20

• Identical performance tests showed,• JPEG2000: 11,432 images served• ECW: 80,483 images served

• CPU overhead,• JPEG2000: 65%• ECW: 23%

Despite equal compression, ECW was 8x faster while using 3x less CPU to generate identical image output.

Real world comparisons• If Landgate were to migrate to,

• JPEG2000–Storage requirements would be the same (assuming lossy)–They would need 4x the hardware and 4x the software to achieve the current

performance metrics• TIFF

–Storage requirements would explode from 6.5TB to 50TB+–They would need to upgrade the whole SAN infrastructure to get the required

I/O and performance• Pre-rendered tile cache

–Tile cache would be in addition to the existing 6.5 TB–To cache *just* the latest Metro South 2010 ECW

– Additional 2 TB of approx 134,217,728 tiles and would take a month to create– Per image!

• For any alternative, time to convert the data would also be significant

But Chris …• ECW is proprietary! *gasp*

• Yes it is, but Landgate uses our extraction technology through the Property Finder to easily extract any imagery from ECW and deliver it to end-users in whatever format they choose

• ERDAS is happy to license the technology but it is not a “free” format. Just like the ESRI geodatabase is not “free”

–The advantages the format provides quickly recoup’s any upfront licensing cost.

• ECW is supported across many, many desktop applications

• Anyway, on to the new shiny feature .. WMTS

What is WMTS?• New OGC protocol to serve tiles

• http://www.opengeospatial.org/standards/wmts• To update Apollo IWS to the official WMTS v1.0 OGC specification

• SLIP Innovation sponsored this piece of work• Complements existing SLIP WMS services• Allows easy integration with consumer mapping apps• Landgate to roll out the new service type at a later date

WMTS Demo

Mobile Integration• Consumer API’s like Google & Bing make WMTS integration simple in 5 lines of code• Check it out now if you like …http://demo.erdas.com.au/wmts/googlemaps/

Thankyou

• Any questions?

Feel free to email Chris.tweedie@erdas.com