Module 3 Visibility Analysis

 For this week's lab assignment in module 3 we were tasked with completing 4 of Esri courses through ArcGIS Online. The 4 Esri courses were Introduction to 3D Visualization, Performing Line of Sight Analysis, Performing Viewshed Analysis in ArcGIS Pro, and Sharing 3D Content Using Scene Layer Packages. 

For the first course Introduction to 3D Visualization the course goals were discovering the advantages of visualizing GIS data in 3D and exploring 3D visualization techniques.

Some of the learnings were that using data visualizations in GIS helps to identify patterns that may not be visible in 2D. It gives you a different perspective of data. It allows users to see content that is vertically stacked. It can add a realistic environmental effect to your 3D scene. You can view 3D visualizing data in 3 different views, a map view which is best for top-down view, or bird's-eye view, of either small or large extents. Or a local scene view, which is best for small geographic extents, in which the curvature of the earth is unnecessary for analysis. And a global scene view, which is best for visualizing your data at a large extent is great for gaining context for global phenomena, such as weather, world populations, or shipping lanes. In the exercise we examined the data of a 2D map using the explore tool to pan around before viewing it in a 3D scene. This exercise showed us the data can be used in both the 2D and 3D maps and scenes and useful for gaining more information about your data. Then we examined the data in a 3D scene. In this scene we used the Navigator tool to navigate around the 3D scene. Then finally learning how to link the views of both the 2D and 3D map views.

For the second course Performing Line of Sight Analysis the course goals were to perform line of sight analysis to determine visibility between observation and target points.

Some of the learnings for this course were using line of sight analysis to solve problems and create information that cannot be done using 2D. Line of sight determines whether two points in space are intervisible. If the terrain hides the target point, one can use line of sight to determine where the obstruction is and what is visible and hidden along the line of sight. In Esri it explains Line of sight as "A line of sight calculates intervisibility between the first vertex—the observer—and the last vertex—the target—along a straight line between the two. A line of sight considers any obstructions provided by a surface or multipatch feature class. Visibility between these points is determined along the sight line". We learned the workflow for determining line of sight staring with determining the observers and the targets. Then the construction of sight lines. Finally determining line of sight. In the exercise using the provided data and adding a connection to the data folder in ArcGIS Pro. We were tasked with exploring the study area using the explore tool. Then we used the Construct Sight Lines tool, this tool creates line features that represent sight lines between one or more observer points and features in a target feature class. Then we used the Line of Sight tool, this tool determines the visibility along sight lines given terrain, which is represented by the input surface, and obstructions, which are represented by the input features. Then we needed to add z information to calculate 3D view distance. We used the Add Z Information tool to do this. Then we needed to remove the line of sight that were obstructing views, to do this we used Select By Attributes to select non-visible lines or that the 3D length is greater than 1,100ft. Then we needed to use the Delete Features tool to delete the obstructed views.

For the third course Performing Viewshed Analysis in ArcGIS Pro the course goals were performing viewshed analysis.

Some of the learnings for the course were learning the uses of the many different visibility tools to model he visibility of the horizon, shadows, and line of sight. The Viewshed tool creates an output that models the areas that are visible from given vantage points. The Viewshed tool is controlled through fields that are added to the input data to control the observation point elevation values, vertical offsets, horizontal and vertical scanning angles, and scanning distances. For the exercise we have the following scenario "You are modeling the new lighting that will be installed for a campground in eastern New York. The campground director would like to start hosting campers in the early spring and wants to install artificial lighting to allow the campers to enjoy more outdoor activities in the evening". Using the data provided from Esri and adding connection and adding the data to the project. We modified the LightLocations layer to reflect the lighting capabilities to the new lights. We added four fields to the Attribute table of the LightLocation layer OFFSETA, AZIMUTH1, AZIMUTH2, and RADIUS. Then we needed to modify the field values for each point. The values are based on the capabilities of the lights. Per the lighting company, the light generates illumination out to a distance of 400 meters, and each light illuminates a 100-degree swath. The lights can be pointed in any direction, but the azimuth settings in the table have been specified to reflect the 100-degree angle of illumination based on their locations within the campground. Then we moved on to creating the viewshed model of the new lighting. Using the Viewshed tool. Then we used Raster functions to model the part of the campground that is lighted by more than two lights. Then we needed to modify height of the lights in the LightLocation Attribute table. Doing this increases the light coverage of the campground. Then we needed to perform a new viewshed analysis with the new values using the Viewshed tool again. Which shows a larger coverage over the campground. Then we needed to symbolize the number of lights in the area. This resulting in showing that they needed to raise the height of their lights to get more coverage from the lights.

For the fourth course Sharing 3D Content Using Scene Layer Packages the course goals were being able to use ArcGIS Pro to author a 3D scene for the purpose of publishing a scene layer package and to publish a scene layer package.

Some of the learnings for the course were, first you needed to start by considering which scene you wanted to work in, ArcGIS Pro allows two viewing modes to display 3D content Global and Local modes. You can use data from a 2D map you just need to add elevation. Next, we learned the workflow for authoring a 3D scene. 1. load data, 2. Display 2D data as 3D layers, 3. Convert 2D data to 3D data. Then we learned some of the best practices for authoring a 3D scene through some tips and recommendation. One being to make sure all of your source data and the scene are in the same coordinate system. Doing this saves time from the geoprocessing tool to have to remove the reprojected layers. Another tip is 3D symbology is required for feature layers to be published and shared. This is because if the layers symbology is not 3D to match the features geometry 3D/z, then the layer will be ignored during export and be reported as a warning. Then we moved on to Authoring a scene from data that was provided from the city of Portland, Oregon. After loading the data, we were tasked with displaying 2D data as 3D layers. Then dragging the layers from the 2D group into the 3D group to be able to define the extrusions. Going to the layers properties in elevation tab and choosing At An Absolute Height to put the building features at a height of zero. Then in Expression Builder using Arcade inputting an expression of $feature.Roof_ELEV-$feature.SURF_ADJ. This allowing the buildings to be extruding at the correct height, but still are not aligned with the surface. Using the Add Surface Information tool to add a field to the trees feature. Then using the Layer 3DTo Feature Class tool to create the Buildings_3D layer and added to the scene, then in that layer's properties in elevation tab choose On The Ground. This will align the terrain. Using the Feature To 3D Attribute tool to add the Trees_3D layer. Then using symbology to update that layer's symbology and then use Symbology By Attribute button to make the 3D symbology mat the Geometry Z-Values. Once that was all set to be able to share on ArcGIS Online we learned the benefits and requirements for sharing scene content. Then the workflow for publishing from a scene layer. 1. Sign in to your organization. 2. Open My Content. 3. Add the scene layer package. 4. Type a title and tags that describe the scene layer package. 5. Check the box next to Publish This File As A Hosted Layer. 6. Add the item. After following that Provided workflow I was able to publish and share the 3D scene.