Cape Town at a Glance - 3D

It took a while to remove all the cobwebs after the long break, but I finally got around to playing with CityEngine 2013 (could have just as well been CE 2014!).

The main talking point this year at the office is the first ever Esri Africa User Conference in Cape Town later in the year. Esri South Africa created an ArcGIS online story map to help guide visitors around the city. I then decided to create a 3D version of that map. This was the result...


The first thing that I noticed with CityEngine 2013 is the new way it displays raster images. When I draped an aerial image over a height map, I saw that raster values with a 0 height (at sea level) were displayed as white. Although the image layer appears to be a null, for cells with height values of 0; it displays the entire terrain once exported.

Aerial terrain layer in CE 2013

I decided to include the Cape Town building footprints in the scene as 3D basemap only. Since the buildings are not really the main focus area of the scene, and used as reference only, I applied a simple Extract rule to extrude all the buildings to their height attribute and set the transparency at 0.8 (1 = fully visible).

Cape Town buildings

The next step was to create simple rules to display the data from the ArcGIS online story map. The 4 feature classes that were used were point features for:

• Breweries (always important!)
• Food and Drink
• Things to Do
• Where to stay

A simple CGA rule then assigned a 3D symbol for each point type:

#GeoBeer

Where to Stay

Food

Things to Do

Using the web scene to display image info

The point feature classes already contained URL information for each point of interest (displaying images). I created a new field which would contain the URL value as part of an IFRAME string. Using Field Calculator in ArcMap the new IFRAME fields were calculated as:

"<iframe height = "410" src = ' " + [URL] + " '></iframe>"

Doing this enabled the web scene to access imagery from the web, once it has been published.

Using an IFRAME to include image information

Also included in the web scene are locations of traffic cameras which monitor the traffic density on some of the major highways. Using an IFRAME string, each camera pulls a live image from the web and displays up to date conditions for that road section.

Live traffic camera

The live feed for the example above can be seen below:

The live traffic feed was obtained from i-traffic.

The web scene provides a fun, very interactive alternative to a normal 2D map.
One of the major changes with CE 2013 is the compression of the web scenes. My previous Cape Town web scene had a download weight of about 30 MB. With more data in the scene, the Cape Town at a Glance scene has a total size of 10MB.

Cape Town

You can visit Cape Town here.

P.s. 1000 points to the person who finds the Clock Tower!