Short Lab 1: ArcGIS Online & Web-based GIS

This problem set consists of two tasks dealing with Web-based GIS, particularly ArcGIS Online. This short lab provides a check to make sure you understand the material. That said, much more understanding of the material comes here – with working through the problem set – than just listening during lecture and following the steps of the tutorial. You are to work independently, but certainly feel free to go back to the tutorials and ask questions of your classmates on that material. However, if you have a question, or are stuck on a particular item in this short lab, limit your questions to the instructors or TA.

The zip file located here: https://env761.github.io/ConsGIS/01_data/AGOL-Lab-Data.zip contains the files needed to complete this assignment.

♦ Task 1

You want to create an interactive map that juxtaposes social vulnerability and flood risk layers with the storm track of hurricane Katrina to visualize the threats posed by the storm. You’ll use ESRI’s Social Vulnerability layer, a layer depicting US Flood Risk zones, and another layer depicting the hurricane Katrina storm track. You will also upload a CSV file of coordinates for a predicted hurricane and “connect the dots” on this map to display the track for this predicted hurricane. Additionally, you will create an ArcGIS Online presentation from your map. We didn’t cover this procedure in any detail in the class tutorials, but see how well you can do with intuition and exploration. ESRI help on these presentations can be found here: http://doc.arcgis.com/en/arcgis-online/create-maps/create-presentations.htm

1a. Use the following specifications to create and share your ArcGIS Online map:

• Create a new map, setting the base map to ESRI’s Oceans basemap layer.

• Browse the Living Atlas content for "Social Vulnerability". Filter results to show only Tile Layers and add the "most relevant" result (sort results on "relevance").

  • Adjust this layer’s transparency to 50%.
  • Set its visibility range to 1:1,500,000 ("Counties").

• Search the Living Atlas content for “USA Flood Hazard Areas” Imagery Layer (provided by ESRI).

  • Shuffle this under the Social Vulnerability layer in your map.
  • Set its visibility range to 1:6,000,000 ("States / Provinces").

• Search ArcGIS Online content for “Katrina track” and add the feature layer provided by "esripress_ig_imagery” to your map.

  • Rename this layer as "Hurricane Katrina".

• Add the point feature contained in the “StormPredictionPoints.csv” file to your map.

  • Symbolize the points so that those with higher Wind(WMO) values are larger symbols. Choose whatever breaks you want: equal interval, quantile, etc., but change the symbol to one that seems a bit more meaningful than a simple dot.

• Manually draw a line connecting the points in the StormPredictionPoints layer. (Note that not all Map Notes templates allow you to draw lines…)

  • Symbolize these lines to be roughly the same color as your storm features.

• Save and share your map with the ENV761 group. Use your DukeID as a tag.

• Enter the URL on the Lab1AnswerSheet Excel spreadsheet. (This can be either the “arcg.is” URL or the long “arcgis.com” URL).

1b. Create a presentation with the web map you just created:

• Zoom to the extent of the modeled storm and set this as your first slide. Title it Predicted Storm Track by <your name>. Show only the storm track, track points, and the oceans base map.
• Zoom to Wilmington NC, zoom out a bit so you can see the storm track and first storm point, and set this location for your second slide. Set the slide’s title to Landfall: Wilmington, NC. Add the social vulnerability and flood risk layers to the slide’s view. Set the base map to OpenStreetMap.
• Zoom to North Carolina and create a new slide. Label it NC. Keep the layers the same as the previous slide, except add the Recent Hurricane layer and remove the USA Flood Risk layer. Show the storm points, storm track, and the USA Flood Hazard Areas. (Don't show the Social Vulnerability layer).
• Do the same as above for West Virginia. Label it WV.
• Copy the first slide and add it as the last slide as well.
• Preview your presentation. In the web page showing your presentation, copy the URL from the browser and paste it into the Excel spreadsheet.

♦ Task 2

In this task, you will quick assemble an ArcGIS Pro Map leveraging ArcGIS Online resources that calculates the area of high forest fire potential (and water) within the viewshed of a forest observation tower.

→ Before beginning, create an ArcGIS Pro project called <netID>_Lab1 (e.g. abc123_Lab1) on your V: drive.

• You will save your map and all files within this folder.
• Create a new Map object in your ArcPro project.

Your first step in the analysis is to load the location of the fire watchtower. This dataset is located on Duke’s ArcGIS online portal, with access constrained to the ENV761 group. (You should already have access to this group; if not contact the instructor.) You may also need to be signed into ArcGIS online to access this dataset from within ArcMap.

• In ArcGIS Pro, search all portals for the Waldo Mountain Lookout feature layer (owner = john.fay) and add the dataset to your map.

Next, you will add National Agricultural Imagery Program (NAIP) data for the state of Oregon to your map to double check that the Waldo Mountain Fire Tower appears to be in the correct location.

• Search for 2011 Oregon NAIP imagery layer within all portals. Add one of the services published by David Mather to your map.
• View the layer’s properties and report the URL of the service in the Excel spreadsheet.
• Zoom to the Waldo Mtn. Lookout tower layer and visually determine whether it’s in the right spot using the NAIP imagery. Do you see something that looks like a fire tower at the location of the point?

Now you’ll need to upload data on fire potential. To do this you need to link to one of ESRI’s Landscape Data servers:

• Create a new ArcGIS Server connection in your project folder, setting its connection to: https://landscape3.arcgis.com/arcgis/rest/services/

  • Expand this connection and add the USA_Fire_Potential layer to your map.

To calculate the viewshed from this tower, we will use one of the on-line tools ESRI makes available to those with an ArcGIS Online organizational account. (You will need elevated privileges set my me before you can run this tool.)

• From the Analysis tab within ArcGIS Pro, select “Ready-To-Use-Tools”, then ViewShed. Open this tool and use it to calculate the viewshed for the Waldo Mtn. tower:

  • Set the input to be the Waldo Mountain Tower feature class.
  • Leave the Maximum Distance option blank.
  • Set the DEM resolution to 90 meters (to save time).
  • The fire tower is 84 feet tall and you are trying to view anything at ground level or above.
  • Generalize the output and fill in the remaining options as they make sense to you.

• Examine the attribute table of the output. Report the viewshed area and perimeter (and their units) in the Excel spreadsheet.

• The Viewshed tool’s output is saved in the computer’s memory. Save a local copy of the viewshed polygon feature class to your project folder so you can retrieve it in case ArcMap crashes.

You now have all the data necessary to calculate the amount of high and very high fire potential within the viewshed of the Waldo Mountain lookout tower. Use these datasets you derived to fill in the remaining values in the Lab1_Answersheet.xlsx Excel spreadsheet. Be sure to fill out the units column as well, and pay attention to significant digits; don’t submit answers that you know are too precise given the data used. (For example, you are not going to know the viewshed perimeter to the nearest centimeter so don’t include any decimal places if your answer is in meters…)

Challenge question

If you have answered the above two questions satisfactorily, you will have earned a solid score for this assignment. However, if you want to demonstrate further mastery of the subject, I have provided the opportunity to do so here.

Calculate the length of the flow path from the Waldo Mtn. lookout tower to the outlet of Willamette River (or wherever the flow path ends). ESRI provides a tool that traces flow paths downstream from a user supplied point. The tool is located on ESRI’s Hydrology Server connection (https://hydro.arcgis.com:443/arcgis/services/) which can be access through your ArcGIS Online organizational account. If options are available, select the finest resolution and do NOT generalize outputs. Enter your answer on the Lab1AnswerSheet.xlsx spreadsheet.

Submission

Put your Lab1 answer sheet in your Project Folder. Zip the folder, which should contain:

• your spreadsheet (.xlsx),
• your ArcGIS Pro project (.aprx),
• your local copy of the viewshed shapefile (.shp, etc.), and
• any ArcGIS Online connection files (.ags) created

And submit this zipped folder to the assignments section of Sakai.