00:01So let me tell you about my trip to Dubai last year.
00:03I was riding through the streets of Dubai and looking around and realizing, why are all these buildings so modern?
00:10So I turned to my friend Hossam and said, "Why are there no old buildings in Dubai?"
00:15And he said, "Well, the answer's simple: the United Arab Emirates is a country that's only 40 years old."
00:21The city, the country really is that modern.
00:25So that created the challenge and the question for our next presentation, which is to answer the question...
00:30...How much has Dubai changed in the last 40 years?
00:34To answer this, please welcome Peter Becker.
00:41Thanks, John. So let me show you.
00:42Here, a map of Dubai, with recent Landsat imagery.
00:49Let me zoom in to the old part of Dubai and change time back to 1975.
00:56Dubai, a small, coastal town, a single runway.
01:01By the year 1990, it had expanded, the town as well as the runway.
01:06By the year 2000, further expansion and more vegetation.
01:12Let's highlight that.
01:15We can see there's coastal development, and by the year 2000, they had built massive islands in the form of palm trees out into the gulf.
01:27By the year 2010, further development along the coast.
01:32But what if we want to actually measure this change?
01:35Well, I can use this tool to find an area of interest.
01:43And the system now computes the areas, returning for me that, in 1975, it was all barren land.
01:52By the year 2000, about 4 kilometers of urban growth; by 1942, over 40...by the year 2010, over 40 kilometers of urban growth.
02:03Vegetation had increased, and interestingly, the water area had actually gone down by about 12 kilometers...
02:10...due to the development of the palms.
02:13Now, what is the basis of this application?
02:17Well, there are three key things here - one, the world Landsat services...
02:22...two, the ability for ArcGIS Server to perform dynamic classification...
02:27...and the integration of these geoprocessing tools into a web application.
02:32So let me show this to you in ArcGIS Desktop 10.1, that many of you already have.
02:38Here, I can search online for Landsat imagery.
02:44This returns me the newly released Landsat services.
02:49They have been extended to include the new GLS 2010 data from the USGS...
02:55...as well as additional radiometric corrections and additional visually enhanced services.
03:00I can add these directly to ArcGIS Online, and they're available for you to use today.
03:08This service is a service that actually shows one of the capabilities of 10.1 to enable a single service to have multiple products.
03:16Here, I can pick the visualization analysis, and you will see the enhanced visual quality of these services.
03:26Let's zoom in to Dubai.
03:27The server performs the processing, returning me the required product.
03:32And from within Desktop, I can add additional enhancements, for example, add a dynamic range adjustment.
03:40As in the web application, we can use time and go back and have a look at what did Dubai look like in the year 2000?
03:49Or, move back forward to the year 2010.
03:55Now, although this is a seamless image service, I can actually get information about the actual pixel values...
04:03...as well as meta information about the individual scenes.
04:08Now, a new capability that we're adding in 10.1 is for ArcGIS Server to perform dynamic processing or dynamic classification.
04:19And to show this, I'm going to bring in this local server connection, and we'll see similar services based on the same imagery.
04:27If we now look at the products available, mind you, I can get to see, for example, this land/water interface...
04:37...or go and have a look at a full class land use.
04:43These same services I can then use in a geoprocessing tool.
04:47Here, I bring it up.
04:49It allows me to define the service's input, allows me to define an area of interest, and then, this will be processed.
05:03The tool is making multiple requests to that service.
05:06The server is dynamically calculating that classification, returning the classification results to the geoprocessing tool...
05:13...which then gets the statistics and generates the required reports.
05:19As soon as these are completed, they can be displayed.
05:22This same geoprocessing service is then shared with the web application to enable the dynamic reports.
05:30So I've shown how the extensive imaging capabilities within ArcGIS 10.1 can be used to measure the growth of Dubai...
05:39...but we know Dubai has also grown with a lot of tall buildings.
05:43And to show you how we can measure the vertical growth, let me introduce you to Vinay Viswambharan...
05:48...from the software development group.
05:57So you just saw analysis and classification done at a city scale.
06:02I want to show you characterization of change at a finer level of detail.
06:06To do this, I need high-resolution imagery.
06:10So here's a WorldView scene over the area of Dubai.
06:14I receive this as raw, unprocessed TIFF files on disk.
06:17Now, one of the biggest improvements we've made in ArcGIS 10.1, the system leverages the metadata that's provided...
06:24...and it can define products automatically.
06:28So as I drag my pan-sharpened product into map, the system pan sharpens, orthorectifies...
06:35...and creates a visually good-looking product on the fly.
06:44The best is yet to come.
06:48So this is the Burj Khalifa, the tallest building in the world.
06:52It's an amazing structure, and that's some beautiful imagery to complement it.
06:57But that's obviously not the most intuitive view of the tallest building in the world.
07:02Using the sensor model information, we can now rotate my view and get a better perspective.
07:15Leveraging the sensor model information and using the meta information...
07:20...we've improved the analytical capabilities of ArcGIS even more.
07:24You can now make measurements off of your imagery.
07:28You can base it off the sensor geometry from the bottom of the structure to the top of the structure...
07:35...or you can make shadow base measurements from the tip of the shadow, tip of the spire, to the tip of the shadow.
07:46When characterizing change, you typically work with historical imagery.
07:51A common problem faced when working with historical imagery, your imagery doesn't line up.
07:58Let's navigate over to another place in Dubai.
08:03So here I have an older image.
08:05As you can see, the change is not quite obvious, but a problem with the image misalignment is a lot more obvious.
08:14These roads, they don't quite line up.
08:18ArcGIS 10.1 can fix this.
08:21We have this magic button.
08:24No, seriously, you'll like this.
08:27I'll bring up the Georeferencing toolbar, I'll hit it, and I'll tell you what it does.
08:32You're going to like this.
08:33The system is computing tie points between the two images.
08:37It's adjusting the images to fit automatically.
08:41Now, this is great for the historical imagery that I'm dealing with.
08:44And like I told you, it's a very simple workflow.
08:47Press a button, pick your images, no tie points, no control points, no check points.
08:52There is no complexity the user needs to deal with.
08:57Just like that, it fits.
09:08You can now compare the two images, automatic georeferencing.
09:14We can now navigate back over to the Burj, compare the two images, lines up perfectly.
09:21For five years, that is a lot of change.
09:25But if you notice, most of the change, much of the change is tall buildings, a lot of vertical growth.
09:32Vertical growth equates to massive change in floor area.
09:37Now, to compute change in floor area, or to quantify change, you need to measure building heights.
09:47So as I zoom out to the extent of Dubai, you can see that's a lot of data collection that I have to do...
09:52...and a larger collection of images to deal with.
09:55So here's where the mosaic dataset comes in.
10:00Now that's a lot of imagery.
10:03It's processed on the fly, and it's fast.
10:11As I zoom out to the extent of the Middle East, 2,500 scenes, GeoEye scenes, two and a half terabytes of imagery.
10:24It's processed on the fly.
10:33I've shown you all of this functionality.
10:36I've shown it to you in Desktop.
10:38But ArcGIS, it's a system, which means we can wrap all of this functionality into a rich, focused web application...
10:46...and I can crowdsource my data collection task to a larger group of people.
10:53So here's my web application.
10:56I've hosted it on my organizational account on ArcGIS Online.
11:01As I bring it up, the application lets me measure building heights and other attributes.
11:07And just like in Desktop, from the tip of the building to the tip of the shadow, I can attribute my building.
11:17Image services, like all of ArcGIS, are time aware, which means I can actually step through these images in time...
11:28...and you can see, the structure was first observed in 2009.
11:35On the right-hand tab, I have my reports populated; I have other statistics as well.
11:43So to answer John's question. How much has Dubai changed over the years?
11:48The city has changed a lot.
11:52With 96 percent of buildings captured by my organization, the approximate increase in the total floor area - 190 square kilometers.
12:03But John, why just numbers?
12:06Using these measurements, I can actually show you what it looks like.
12:13So here's the beautiful city of Dubai at night.
Analyzing Imagery and Change Over Time
Peter Becker and Vinay Viswambharan demonstrate how Dubai has changed in the last 40 years.
- Recorded: Jul 23rd, 2012
- Runtime: 12:30
- Views: 204
- Published: Aug 30th, 2012
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