Esri and the 3rd dimension

With Esri’s ever expanding software stack it is sometimes difficult to keep track of the variety of software solutions available. One of the main areas of growth is Esri’s collection is its answer to 3D GIS. Fully utilising the extra dimension has come difficult to the GIS sector in the past (which is historically mostly two-dimensional in terms of application). Esri’s recent focus on developing a 3D stack which fully embraces three-dimensional analysis, content generation and visualisation with the emphasis on sharing 3D scenes with non-technical users has led to mainly two desktop applications, ArcGIS Pro and CityEngine. This blog post will have a look at both of these applications by discussing the capabilities and when to use them through a typical use-case for an area around central Johannesburg.

Intro
CityEngine or ArcGIS Pro

ArcGIS Pro:

ArcGISPro

ArcGIS Pro allows users to seamlessly integrate traditional two-dimensional GIS with 3D data in a single application interface. Using the 3D Analyst extension a user can perform various 3D analysis on GIS data including line of sight, volumetric calculations, viewshed calculations as well as working with LAS datasets, as well as the traditional GIS analysis methods like proximity, overlay and statistical analysis. For more information regarding the 3D Analyst extension visit: http://www.esri.com/software/arcgis/extensions/3danalyst.

The image below shows a Johannesburg scene showing 3D textured buildings, analytical representation of trees and extruded polygons showing the various zones and height restrictions of the buildings. This gives the user the ability to quickly see which building exceed their height restrictions.

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Overlay 3D buildings and zonal restrictions in ArcGIS Pro

Next we need to calculate how the shadows in the city change over course of a specific day, and share the result with external users.

Use the Sun Shadow Volume geoprocessing tool (3D Analyst) to calculate the shadow volumes. In the example below the analysis were done between 08:00 and 16:00 for every two hours.

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Sun shadow volume tool

The resulting multipatch represents the shadow volumes created by each building at a specific time. ArcGIS Pro has the ability to cycle through these time-enabled data to create a seamless animation of the shadow movement.

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Shadow movement over the course of the day

Share the scene to either ArcGIS Online or Portal with ease. An example web scene for of the shadow analysis mentioned above can be viewed here.

*The next blog post will focus on the various 3D sharing techniques available in the ArcGIS Platform

ArcGIS Pro is a powerful tool for performing 3 dimensional analysis on GIS data. However, although ArcGIS Pro has 3D editing capabilities, its primary function is not 3D content creation. CityEngine on the other hand was designed especially for quick content generation on a large scale.

CityEngine:

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CityEngine’s ability to dynamically create and compare urban scenarios quickly makes it a favourite among urban developers, local governmental authorities, township planners as well as the entertainment industry.

The key behind CityEngine’s quick content generation is its own procedural scripting language called CGA. These scripts or rules are basically a set of sequential tasks that guides the software to create accurate 3D geometries.

By applying different rules to the same datasets, we are able to generate various 3D representations. In the example below, we can see that in the larger view a more realistic scenario is generated displaying textured buildings and highly detailed trees. The inserted image shows the same datasets represented differently to produce a more analytical scenario of the data.

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Using CGA rules creates multiple scenarios quickly using the same data

In another example, an urban designer might want to compare scenarios for a redevelopment project. In the image below CityEngine is used to compare high rising buildings, office spaces and apartment building designs.

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Comparing redevelopment strategies in CityEngine

A CityEninge scene can be easily shared in a variety of ways. These include:

A CityEngine webscene is a static version of the CityEngine scene. All models, terrains and networks generated in CityEngine is compressed into a single .3ws file. This file can then be added as an item in ArcGIS Online or Portal, and when opened creates a browser based 3D environment that allows user-driven navigation and interaction. An example of the CityEngine web scene can be found here.

The image above shows examples of:

  • comparing real-world and analytical scenes (top left)
  • comparing redevelopment scenarios (top right)
  • adding HTML embedded attributes such as Google Streetview (bottom)

Datasets can also be exported to a Scene layer package. A Scene layer package has the ability to publish hosted scene layers which represents 3D data as a feature service, when added to either ArcGIS Online or Portal.

CityEngine also has the ability to share a scene as a 360 Virtual Reality experience. This creates a .3vr file which can be shared to ArcGIS online. Using a Samsung Gear VR headset along with the ArcGIS 360 VR app from Esri Labs, you are able to explore scenes in a fully immersive 3D virtual reality.

Find the Johannesburg 360 virtual reality scene here.

VR

For more information about creating a 360 VR experience in CityEngine go to the Esri CityEngine Help.

CityEngine & ArcGIS Pro combine to show CCTV coverage in 3D

As part of our Modelling Reality in 3D series, this post looks at the Esri Africa User Conference demonstration of CCTV camera placement in 3D.

Modelling reality in 3D

A prominent United Nations study notes that the share of Africans living in urban areas is projected to grow from almost 40% in 2010 to over 60% by 2050. With the expected rate of population growth on the continent. This increase in urbanisation can lead to economic growth, transformation, and poverty reduction. However, without proper planning the possibility of increased inequality, urban poverty and associated crime exists.

One of the areas to address is crime and this needs to be done in a more systematic way. Applying geography will help us do that.

The aim of the demonstration was to show the location and coverage of CCTV cameras in downtown Johannesburg. The objective was to find the optimal coverage area in 3D by altering some of the camera attributes such as angle, direction and length. CityEngine was used to create the CCTV coverage rules, and ArcGIS Pro’s analysis abilities were utilised to determine the covered areas.

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CityEngine:

Step 1 was to create a CityEngine rule that creates 3-dimensional shapes representing the visible area of each camera. The CGA rule is shown in the images below:

Attributes

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Note that the Width and HorizontalRotation attributes derive their values by calling the getWidth and getRealDirection functions, respectively.
The getWidth function uses a Pythagorean algorithm to calculate the width (length of the opposite triangle side) by using the CameraAngle and ViewLength attributes.

The getRealDirection function converts the azimuth attribute (N= 0, E = 90, S = 180, W = 270) so that the coverage area has the correct real-world direction. See how altering these attributes effects the coverage areas in the video below.

 

Rules

The image below show the rules used to generate the viewing area:

  • Object: The Object rule uses the i-function to transform the CCTV point to an existing triangular Collada shape and then calls the Rotate rule.
  • Rotate: The rotate function uses the VerticalRotation and HorizontalRotation attributes to change the angle of the viewing area, before calling the Scale rule.
  • Scale: Finally the s function scales the viewing area according to the Width, VerticalHeight and ViewLength attributes. The rule then centres, colours and changes the transparency of the 3D viewing area.
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ArcGIS Pro

The second part of the presentation showed how these CityEngine rules can be implemented in ArcGIS Pro for further analysis. Some of the analytical capabilities of ArcGIS Pro are listed below

  • Display the 3D view areas alongside existing 3D content (such as buildings) in ArcGIS Pro.

 

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  • View feature information in a pop-up. This can include attributes, pictures, videos or HTML attributes such as an i-frame of the Google Street View.
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  • Calculate the % of the area covered by the cameras. The image below shows the Before and After scenes after additional cameras (blue spheres) were added. We can analyse the coverage of the new additions and compare the calculated values to the previous scenario.
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By combining CityEngine with ArcGIS Pro we were not only able to realistically model reality, but also perform accurate 3D spatial analysis.

Determining Solar Potential for Rooftops of Multipatch Feature Types

Part of the Modelling Reality in 3D series

Often times there are problems that simply have to be solved in 3 dimensions in order to attain the appropriate results. This doesn’t have to be scary though! Through this series of blog posts – Modelling Reality in 3D, we’re going to uncover some simple and practical uses for 3D GIS.

In this demo we’ll be using tools that are nestled away in the Spatial Analyst extension and often overlooked in order to determine the production potential of rooftops of multipatch feature classes (Esri’s geometry type for 3D features) for generating electricity harnessing the power of the sun!

For this exercise we’ll be using a multipatch feature class from HERE’s 3D Landmark dataset of the Dome in Northgate, Randburg as its construction lends itself quite nicely to an exercise of this kind. This workflow should be perfectly acceptable to use on any other multipatches with a ‘roof’ area with minimal tweaking to the model as long as you keep in mind that this model assumes that skyward facing portions of the multipatch are rooftop areas.

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The high level workflow and tools used for this exercise are as follows:

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A toolbox can be downloaded HERE in which you can delve further into the parameters set for this demo. We will be discussing it on a conceptual level on the blog.

 Prepare Usable Roof Area

This model will be calculating the maximum potential that can be harnessed by a rooftop, therefore we need to define what this region is. The Area Solar Radiation tool, which we’ll discuss later on, requires a DEM as input and provides results based on a square metre, so we know that this rooftop needs to be represented as a DEM and to make calculations easier later on we will be using 1 metre squared pixels.

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Using the Slope and Raster Calculator tools from the Spatial Analyst Extension we extract all of the areas with a slope of 36 degrees or less – this gives us a good approximation of the rooftop area that could hold a photovoltaic cell – we then use a number of other raster-based tools from this extension to clean up the roof area we will be working with.

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Using the rooftop area we then extract from the DEM of the building only the portions of the DEM that relate to the roof area that we require for our analysis.

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Calculate Global Solar Radiation

Using the Area Solar Radiation tool we determine the global radiation expected to hit the roof of this building in an entire year – this is a combination of both the direct and diffuse radiation and the pixel values have the unit of watt-hour per square metre. In this exercise I used all of the default values as they were well suited for the area in which this building lies, however you can change a number of parameters related to the amount of light that would eventually reach your rooftop.

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Additional outputs include views of both the direct and diffuse radiation which make up the global radiation as seen above as well as a DirectDuration ‘map’ which indicates in hours the amount of time each pixel would receive direct solar radiation.

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Prepare Basic Contextual Statistics

Now that we have a result, we need to make sense of it and often times the best way to about this is by providing context. The following statistics were calculated based on the global solar radiation values.

Statistic

Result

Assumption

Total Global Radiation

3 192 297 067 wH

Conditions modelled in the Area Solar Radiation Tool are correctly indicative of an average year for the site.

Total Area

21 189 m2

Solar Electricity Potential

3 192 297 kWh

Largest Possible System Cost

R35 455 711

Based on a solar panel with the following specifications:

Module Output: 310W

Cost: R3246.86 per unit

Size: 1.940352 m2

http://www.sustainable.co.za/jinko-jkm310p-310w-solar-panel-pallet-of-28.html

Largest Possible System Size

3 385 200 kW

Solar System Potential

4 077 473 kWh/year

Based on a running time of 5 hours of maximum output for the largest possible system every day for a year with loss factors accounting for temperature (6%), dust (7%), wiring (5%) and DC/AC conversion (20%)

Number of households that could be powered per month, either:

Low Consumption

680

500kWh per month

Medium Consumption

227

1500 kWh per month

High Consumption

113

3000 kWh per month

Conclusion

Obviously this approach is based on a number of assumptions which would be made clearer on a true project of this nature and scale. A number of factors have also been disregarded such as the weight of the system and how much load the roof structure could bare. What this model does do is quickly provide an indication of the potential of rooftop-based solar energy in South Africa and hopefully showcases both the power of tools within our software within a 3D context!

ArcGIS Earth is here!

ArcGIS Earth Logo

Version 1 of ArcGIS Earth was officially released mid-January 2016. The application offers functionality to share data in a similar way that Google Earth does.

For Esri customers ArcGIS Earth offers additional value as it makes data viewing in realistic 3D and data sharing possible across the platform – from the desktop, mobile, server or custom developments, the same authoritative data can now be viewed in ArcGIS Earth.

Some advantages of ArcGIS Earth are:

1. Basemaps

ArcGIS Earth offers a choice of 10 global Basemaps ranging from street maps, to terrain and imagery at the click of a button. Simply set the Basemaps to suit the data that is displayed. This means you always have access to high quality, global data that is being constantly updated for you.

ArcGIS Earth screen shot

Multiple datasets from various online or offline sources can be viewed in context of a Basemaps of your choice.

 

2. Collaboration & Content

If you are an existing Esri client with a Portal (or ArcGIS Online) identity you have full access to your organization’s authoritative content in the form of map and feature services, which means you can do your work quicker and easier than before. Sharing data requires no conversion, saving you time and money.

3. Ownership & Security

With ArcGIS Earth you have the ability to share GIS content that is 100% secure in an existing ArcGIS Online or Portal environment.

  • The level of data access is controlled by your Portal identity. Users can only access data they have been granted access to.
  • When information is added to ArcGIS Earth it remains the property of organisation/person who published it. This is different from other software providers may keep data even after you have removed it.
  • It is not possible to extract or download data from ArcGIS Earth. You can share a view of your data without giving it away. This is great because you can rest assured that your company’s data is safe and secure while using the latest technology to do your work.

4. Save your last session

There are several setting that can be customized. Among them is the possibility to have the Start-up view to continue where you left off. This setting remembers your location, Basemaps and all the other layers that were added during your last session. This can save you time when starting to work each day!

5. Limitations

ArcGIS Earth is great as a free tool for realistic 3D data visualization and sharing data in collaboration with your colleagues and customers. As with all software, there are currently a few limitations:

  • The file based data formats are limited to shp and kmz/kml. If you wish to use data from other Esri sources it must be published to a map or feature service first.
  • Where the symbology of file based features can be changed and the popups are visible, this is not the case for feature and map services. It is not possible to change the symbology or transparency of service layers to view data in context of layers below. It is also not possible to label or set popups for a service layer.

In conclusion

ArcGIS Earth version 1 has many useful features and boasts unrivaled global Basemap content. It is a great way to share your data securely with anyone, any place, anytime. So, have a go! You can download it for free.

 

Modelling Reality in 3D with ArcGIS – Blog Series

modelling reality - logo

Welcome to 2016! This is going to be a bumper year on the Esri South Africa blog so be sure to keep checking back for new content (or you can subscribe using by clicking the FOLLOW US button on the right).

Following our successful demonstration of CCTV camera placement at the Africa User Conference, we are pleased to introduce a new blogging series that will showcase some new and innovative ideas for leveraging the power of 3D modelling and analysis within the ArcGIS Platform. The entries will be created by our team of 3D experts here at Esri South Africa and will include step by step guides on how to do it yourself.

If you have any specific requests for 3D modelling or analysis scenarios, please drop us a line using the comments below.

The first entry in the series, entitled “Determining Solar Potential for Rooftops using Multipatch Feature Types”, will be available next week!

– Richard