Performance and the GeoWeb
One of the most frequently raised issues in relation to the GeoWeb is that of performance. Since the GeoWeb builds on XML and Web Services technologies this should bot be too surprising. XML provides redundant description of the content and the structure of the content which is assumed to be known by the creator or the consumer in the case of binary formats. Note further that XML is not a format and hence provides an additional isolation layer from the file structure. None of this comes without a price.
Performance than needs to be looked at in the proper light. We are likely familiar with the nice dataset demos of companies like Navteq - where one zooms from a continential view (USA, Europe) to street level in a second or so. Very impressive. One must ask though, if this is the issue that the GeoWeb is trying to solve. We need to look at that view of performance against another one implicitly expressed by Jack Dangermond in remarks to a HomeLand Security Conference following the Katrina disaster. Here it is not so much as "how fast" but can we do it - or can we do it fast enough (minutes to hours) to be of any use to anyone. In Jack's words:
‘We're not very good at bringing all this together now –we're maybe pretty good at it if you look at it one city at a time. But I have a vision that we could be good at it across the nation at some point in the future.”
’Jack Dangermond, President of ESRI, addressing the company’s Homeland Securities event,
in reference to Hurricane Katrina’s rescue efforts.
So speed is very much a relative matter. This is not something that is easily overcome by narrowly defined binary formats - it requires rich expressiveness and some ability to self document the data - precisely the things that XML and Web Services (hence GML, WFS) are designed to do.
Another way of looking at things - is to see how fast to things change - it is neat if I can send you a big file (note that the file format technologies always lead us in this direction) containing hundreds of thousands of features - and not so neat if I send you the same file tomorrow when only 5-10 of these features have changed. If my technology enables sending only the changes (and does so in a transparent or nearly transparent manner) that may be far more efficient and faster than one that leads us to wholesale file exchange. The GeoWeb is thus more about transactonal synchronization of datasets then copyng them over and over again from one place to another. Seen in this light we see that XML and Web Services (GML, WFS, WRS) offer a route to greatly increased overall performance - in the manner that matters for real business applications.
Performance than needs to be looked at in the proper light. We are likely familiar with the nice dataset demos of companies like Navteq - where one zooms from a continential view (USA, Europe) to street level in a second or so. Very impressive. One must ask though, if this is the issue that the GeoWeb is trying to solve. We need to look at that view of performance against another one implicitly expressed by Jack Dangermond in remarks to a HomeLand Security Conference following the Katrina disaster. Here it is not so much as "how fast" but can we do it - or can we do it fast enough (minutes to hours) to be of any use to anyone. In Jack's words:
‘We're not very good at bringing all this together now –we're maybe pretty good at it if you look at it one city at a time. But I have a vision that we could be good at it across the nation at some point in the future.”
’Jack Dangermond, President of ESRI, addressing the company’s Homeland Securities event,
in reference to Hurricane Katrina’s rescue efforts.
So speed is very much a relative matter. This is not something that is easily overcome by narrowly defined binary formats - it requires rich expressiveness and some ability to self document the data - precisely the things that XML and Web Services (hence GML, WFS) are designed to do.
Another way of looking at things - is to see how fast to things change - it is neat if I can send you a big file (note that the file format technologies always lead us in this direction) containing hundreds of thousands of features - and not so neat if I send you the same file tomorrow when only 5-10 of these features have changed. If my technology enables sending only the changes (and does so in a transparent or nearly transparent manner) that may be far more efficient and faster than one that leads us to wholesale file exchange. The GeoWeb is thus more about transactonal synchronization of datasets then copyng them over and over again from one place to another. Seen in this light we see that XML and Web Services (GML, WFS, WRS) offer a route to greatly increased overall performance - in the manner that matters for real business applications.
There are technologies like that already: rysnc and a(n) xml/gml file - will only copy the changes. (Comment this)
I do like the part about moving to more expressive data formats. The distribution and useage of vector data has been considerably hobbled in some respects by the widespread adoption of the shapfile format- yes it is easy to parse- but it contains none of the topological, or in some cases when the .prj file is missing, spatial reference information. The geotiff format is a nice example of one such expressive format, which maintains reasonable performance. (Comment this)
As to not being connected to the Net - we are talking GeoWeb - so we are talking about being connected at least some of the time. This of course does not exclude bulk loads of data via other means with subsequent updates via WFS to maintin "synchronization".
The idea is to move away from file transfer altogether.
Geotiff is good as far as it goes - but offers nothing in terms of radiometry description (range description) and is not really extensible wrt coordinate reference systems. (Comment this)
animal stuffed webkinz
animal webkinz
animal code webkinz
webkinz dogs and more
free webkinz dog
free webkinz panda
webkinz
cheat code webkinz
cheat code pet webkinz
cheat code secret webkinz
cheat code webkinz world
cheat code money webkinz
webkinz world
cheat webkinz
code webkinz
webkinz welcome world
code secret webkinz
love puppy webkinz
child webkinz welcome world
recipe webkinz
webkinz world.com
cheeky dog webkinz
black lab webkinz
ganz webkinz world
ganz site web webkinz
ganz site web webkinz welcome
ganz webkinz welcome world
new webkinz
webkinz welcome
ganz webkinz
pet play webkinz world
code free secret webkinz
bear polar webkinz
game webkinz
code free webkinz
recipe secret super webkinz
toy webkinz
bunny sherbert webkinz
game pet play webkinz world
code secret webkins webkinz
web webkinz
cat cheeky webkinz
recipe secret webkinz
store webkinz
cat webkinz
code secret toy webkinz
panda webkinz
google webkinz
code pet plush secret webkinz
kinz lil webkinz
pug webkinz
googles webkinz
lil webkinz
monkey webkinz
ganz pet play webkinz world
clothes webkinz
search webkinz
leopard webkinz
valentine webkinz
picture webkinz
rabbit webkinz
cheat money webkinz
bullfrog webkinz
hippo webkinz
chihuahua webkinz
new recipe webkinz
pet webkinz
frog webkinz
koala webkinz
password webkinz
cheeky monkey webkinz
plush toy webkinz
dog webkinz
retired webkinz
cheap webkinz
bunny sherbet webkinz
horse webkinz
bulldog webkinz
com webkins webkinz
tiger webkinz
ca webkinz
gorilla webkinz
golden retriever webkinz
collection webkinz
cat persian webkinz
accessory webkinz
unicorn webkinz
cow webkinz
frog tree webkinz
webkins webkinz
free webkinz
locator store webkinz
cheeky webkinz
bull dog webkinz
find webkinz where
bear black webkinz
shop webkinz
penguin webkinz
webkinz yorkie
pig webkinz
cheat webkinz world
ganz site web webkinz world
recipe webkinz world
code secret webkinz world
recipe secret webkinz world
game webkinz world
play webkinz world
pet webkinz world
web webkinz world
cheat kinzcash webkinz
cheat tamagotchi webkinz
cheat ganz site web webkinz
cheat kincash webkinz
cheat secret webkinz
cheat game webkinz
cheat recipe webkinz
any cheat there webkinz
cheat tamagotchi toy webkinz
code unused webkinz
code com secret webkinz
code tag webkinz
buy code secret webkinz where
cheeky code dog secret webkinz
code webkinz xom
code pet secret webkinz
code free new pet webkinz
code pet webkinz
code friend webkinz
code secret tag webkinz
code love puppy secret webkinz
new pet recipe webkinz
food recipe webkinz
book recipe unofficial webkinz
banana dome recipe webkinz
recipe stove webkinz
holiday new recipe webkinz
ganz recipe webkinz
blender recipe webkinz
book recipe webkinz
cookie recipe tornado webkinz
recipe sandwich webkinz
rare recipe webkinz
webkinz welcome world.com
black lab new webkinz
game ganz site web webkinz world (Comment this)