Using analytical tools in ArcGIS Online to determine where populations vulnerable to flooding and landslides exist in Boulder County, Colorado.

Transcription

1 Using analytical tools in ArcGIS Online to determine where populations vulnerable to flooding and landslides exist in Boulder County, Colorado. Estimated Time to complete: 1-2 hours Learning Objective: This exercise will introduce the student to ArcGIS Online and some of its more advanced online mapping features. Specifically, o Student will demonstrate the use of web mapping tools to study and develop possible solutions to real world problems. o Student will demonstrate basic proficiency in map reading, interpretation, and design principles, including map projections and the geographic grid. o Student will identify, explain, and interpret spatial patterns and relationships, such as how places are similar and different, the nature of transitions between places, and how places are linked at local, regional, and/or global scales. o Student will describe and demonstrate how to access different sources of data, describe the process of creating data, and discuss the fundamental concepts of data quality and uncertainty. o Student will describe and provide examples of how geospatial technologies are being applied in the areas of transportation, the environment, local government, disaster managements, business, and other areas. Platforms: PC, MAC, or UNIX. Software Tools Required: Web browser with high- speed Internet Access. What do you need to turn in? There are a series of imbedded questions (clearly labeled) within Part II of this document (along with requested screen shots). In order to gain credit for this exercise, you need to turn in the answers to these questions as well as the associated screen shots. The document should be submitted in Word format, Text format, RTF format, or a.pdf file. Credits: This project was created by Joseph Kerski, Esri and edited/revised by Ken Yanow, National Geospatial Technology Center of Excellence. 1

2 Problem statement: Because of recent devastating floods that occurred in September 2013, the Boulder County Office of Emergency Preparedness, hearing of your excellent GIS skills, has asked you to prepare an assessment of the most vulnerable lands in the county to future flooding and the people in those affected areas. Your final assessment will include a spatial analysis of these lands and people. You will consider floodplains, geologic hazards, land cover, soils, and demographics in your assessment. Your analysis workflow will be as follows: 1. Filter Floodplains layer to only consider areas that are truly floodplains. 2. Filter geologic hazards layer to only consider major geologic hazards. 3. Consider areas near floodplains: Use Proximity to Buffer floodplains by 200 meters. 4. Dissolve the buffer s internal polygons for efficiency in analysis. 5. Intersect the dissolved floodplains buffers with major geologic hazards. 6. Sort on the largest resulting polygons and choose the largest ones. 7. Enrich the data with tapestry, wetlands, and group quarters data. Go to ArcGIS Online ( NOTE: In order to utilize the advanced features of ArcGIS Online, you must have an Organizational Account (a Public Account does not open up all of the ArcGIS Online features. If you do not have an Organizational Account, you can sign up for a free 60- day trial. See the Appendix at the end of this document for account set- up instructions.). To access the flood map (by Kerski), click on the following link (or, cut and paste into your browser): b480b3 Note: if you get a Layer did not draw completely error, click on the zoom tool to zoom closer into the map. Once you get to the map, on the top right corner of the screen select sign in (see the image below). Next, sign into your ArcGIS Online Organization Account. Be sure to click the check box next to keep me signed in. When you sign in, you will be taken back to the Boulder map. 2

3 Click the Save icon, and Save as the map so that you are working with it in your own organizational account. Next, click on the Basemap link. Select Imagery. Now, in the Table of Contents, click on the Show Contents icon. Turn off both the Geologic Hazards Layer and the Floodplains layer (click on the box next to the layer name in order to remove the check- mark). Analyze the terrain (zoom in and out to explore the terrain). Turn the Floodplains Layer back on by clicking on the box (the check- mark will once again pop- up). Now, click on the pull- down arrow that is adjacent to the Floodplains Layer. 3

4 Select Transparency. Set the transparency level to 50%. Now, answer the following question: 1) Briefly describe the terrain of Boulder County and indicate the general direction that the rivers run in the county. Notice that the floodplains layer covers all land in Boulder County. Click on the Bookmarks link (top right of the screen) and select the Floodway Illustration bookmark. Click the arrow adjacent to the Floodplains Layer and set the transparency to 100%. Take a look at the imagery to observe what features are found in this area. Now, set the transparency to 0%. Click on the largest polygon that you see (experiment with the map if you like by clicking at different locations on the screen). You will notice that the field named Floodway contains the text Floodway for the largest polygon. 4

5 Click on other polygons in the area and you will notice that most of the other polygons contain no text in the field Floodway. Thus, not all of these lands are truly floodplains. NOTE: you can remove the query window (that contains the polygon information) by clicking on the x at the top- right side of the window. In order to consider floodplains in your analysis, you need to select, or filter only those polygons that are truly floodplains. Click on the Bookmarks again and select the Boulder County bookmark. Zoom into the map if needed. Click on the pull- down arrow next to the Floodplains layer in the Table of Contents. Select Show Table. When you Show Table you are examining the attribute table of a data layer. This is like looking at the I or Information part of your GIS, whereas looking at the map is like looking at the G part of GIS. The map and the table are linked, which illustrates the S part of GIS the System that integrates the map and the database, or set of tables. 2) How many features are in the floodplains layer? Now, let s filter the floodplains layer to select the areas that are true floodplains. Click on the pull- down arrow to the right of the Floodplains layer again and select Filter. Fill in the Filter dialog box as noted below so that floodway is FLOODWAY (see image below): Click Apply Filter. Open the table again for the floodplains layer (if you previously closed it). 3) Now how many features are under consideration in your data set? 4) Describe the spatial pattern of the true floodplains on your map (that is, where on the map are the floodplains located?). 5

6 Save your map now and frequently during this exercise. This is important in desktop GIS analysis and even more important in running analysis on the web! Turn off the Floodplains Layer (by clicking on the check- mark adjacent to the Floodplains Layer in the Table of Contents) and turn on the Geologic Hazards layer. Click on the legend icon in the Table of Contents. You will only consider the major geologic hazards. 5) Describe the spatial pattern of major geologic hazards in Boulder County. Click on the Content tab select Show Table.. Click the pull- down arrow for the Geologic Hazards Layer. Now, 6) How many features are in the Geologic Hazards layer? In the table, which field name contains the information on whether the hazard is major, minor, or moderate? Use the pull- down arrow as you did for Floodplains and Filter the Geologic Hazards to show only the hazards classified as a Major Hazard. 7) What expression did you use in your Filter statement? 8) How many features are now under consideration? Save your map again. Turn the Floodplains Layer back on. Click on the Bookmarks link and select City of Boulder. Next, click on the pull- down arrow to the right of the Floodplains layer. Now, select Filter. Next, select Remove Filter. 6

7 Recall the problem statement: you will consider all areas within 200 meters of the floodplains. In order to set- up a 200- meter buffer to analyze, click- on the pull- down arrow to the right of the Floodplains Layer again and select Perform Analysis. Now click on the Use Proximity button and then click on the Create Buffers button: In the dialog box, enter 200 and use the pull- down menu to select meters. This will create 200- meter buffer zones around the floodplains. Name your Result Layer Name as Floodplains 200m Buffer. It is important when you are working in a GIS to name your layers appropriate so that you (and possibly, others, if you share your data) will be able to efficiently know what your data layers are and be able to use them. 7

8 Now, select Run Analysis. It will take a few minutes to complete the analysis, so please be patient. Save your map again. Now, select the pull- down arrow adjacent to your new Floodplains 200m Buffer. Select Filter. Use the expression Floodway is Floodway. Select Apply Filter. If your Floodplains Layer is still on, be sure to remove the check- mark for that layer to turn it off. Your map should look like the following: Zoom into one of the floodplains. Click on the measure tool. Be sure to select the Distance tool. Use the pull- down menu to select Meters for your unit of measurement. Now, click the tool on one side of the buffered zone and drag the line to the other side of the buffer zone. Double click when you get to the other side. 8

9 9) Are the 200- meter buffer zones across the entire buffer or 200 meters from the middle of the floodplain to the edge of the buffer boundary? Pan around your map. Notice that the floodplain buffers are composed of many small polygons because the floodplains layer was also composed of small polygons. To make your next analysis steps run faster and more efficiently, particularly because you are operating in a web environment, you should dissolve the boundaries of your floodplain buffers. Dissolving will remove common boundaries between the many polygons that you have just created. First, click on the Bookmarks link and select the Boulder County bookmark. This will take you back to a full extent view of your data. Go to Perform Analysis for your Floodplains 200m Buffer layer. Click Manage Data then Dissolve Boundaries, and fill in the dialog box as noted below (saving the results in your personal folder, not in jkerski ). Name your result Floodplains 200m Buffer Dissolve : 9

10 Select Run Analysis. When the process is complete, Show Table for the new dissolved layer and answer the following question: 11) How many features are in your dissolved layer? What is the total area (in sq. km)? For your next step, you will intersect your dissolved 200m floodplain buffer with the geologic hazards that are filtered so that we only consider Major Hazards. Save your map again. Click on the pull- down menu for the Geologic Hazards Layer. Select Filter then select Remove Filter. Next, on your dissolved layer, select Perform Analysis again. Select Manage Data, and then Overlay Layers. Use the Geologic Hazards Layer for your overlay layer. Choose Intersect for the overlay method. Name your intersect layer Intersect Floodplains Major Geologic Hazards : 10

11 Select Run Analysis. Next, click on the pull- down arrow for the new Intersect layer. Select Filter. Use the expression DESCRIPTIO is Major Hazard. Click Apply Filter. Now, turn off all of the layers accept for the Intersect layer. It might be difficult to see the intersected layer, so let s change the symbol. Click on the pull- down arrow for the Intersect layer. Select Change Style. Under Drawing Style click the Options button. Next, click the Symbols link. Change the color to something bright (like yellow). Click Ok. Click Ok. And then click Done. Click pull- down arrow for the Intersect layer and select Zoom to. Turn the Dissolve layer back on. 12) Describe the pattern of the intersected layer on your map of Boulder County. Where are the points of intersection located? These are relatively high danger areas of both flood zones and major geologic hazards. How many features are we talking about (if necessary, Show Table for the Intersection layer). Your table for the Intersection layer should still be open. If not, Show Table for the Intersection layer. What we want to do now is filter the intersected layer to only consider the largest areas of danger; those zones that are greater than 0.4 square kilometers in area. On the top- right of the table, click the Table Options pull- down arrow. Next, click on Filter : Click the Edit tab. Now, click the Add another expression link. 11

12 Your new expression should be Area in Square Kilometers is greater than 0.4. Click Apply Filter. 13) How many features are you now considering? Save your map again. Next, let s enrich the layer with additional data that will be pulled directly from the ArcGIS Online cloud. On your intersected layer, choose Perform Analysis, Data Enrichment and Enrich Layer. Click the Select Variables button. From the Data Browser window, select the following (be sure that the pull- down window along the right- side of the window says United States ): 1) Find and click Landscape (the Landscape link will be on the second page of the Select Variables window. In order to get to it, simply click on the right- facing arrow on the right- side of the Select Variables window.). Next, click Landcover. Click on the box adjacent to Percent of Wetlands (NLCD). 2) Next, click the Back button. Click Back again. Now, click on Population. Click on Group Quarters. Select 2010 Group Quarters Population (U.S. Census). 3) Next, click the Back button. Click Back again. Click on Tapestry (2015). Select 2015 Top Tier (1A) Tapestry Households (Esri). 4) Click Apply. Name the result layer name Enriched Intersect Floodplains Major Geologic Hazards, and Run Analysis. 12

13 NOTE: If your layer does not show on your map, you can add it by clicking on the Add pull- down menu and then Search for Layers in My Organization. Now, Show Table for your enriched layer. Notice your new fields that have been enriched from data on the ArcGIS Online cloud (use the bottom bar to scroll through the table. Let s say your research from Boulder County concludes that areas containing a greater amount of wetlands are potentially more hazardous during floods, because they are generally flatter, spreading floodwaters over a greater amount of terrain. Your research also shows that the more people that live within group quarters (nursing homes, residence halls, group homes, etc. that are owned and/or managed by an organization providing housing and/or services for the residents), are more vulnerable to being impacted by floods and other natural hazards. Select (by clicking on the row in the table) the polygon that contains the most wetlands percentage and the most people within group quarters. Now, click the Table Options pull- down arrow and select Center on Selection. 14) Describe where this polygon is located in Boulder County. Change the basemap to Topographic and tell me what streets run through the area and what the name of the community is (HINT: you will need to zoom into the selected polygon). From your analysis, you have found the most susceptible location in Boulder County, effecting the most people, with regards to floods and geologic hazards. Next, click on the pull- down arrow for the Enriched layer and select Zoom to. Save your map again. Next, click the Share link (found at the top of the screen). Click the box for Everyone (public), and keep the Share current map extent check- box checked. You can copy- paste the map link that is displayed and send it to anyone you want so that they can see your map. Click Done. 13

14 You have also enriched your data with Tapestry segmentations. The tapestry segmentation is a way of segmenting US residential areas into 65 distinctive segments based on socioeconomic and demographic characteristics to describe US neighborhoods. Tapestry 1: Top Rung, 9 is Urban Chic, 22 is Metropolitans, 23 is Trendsetters, and 41 is Cozy and Comfortable. Skim these 4 Tapestry segmentations (and any others that exist in your table) using the following document: Communicating Your Results Congratulations! You have finished your analysis and are ready to present your results to your stakeholders at Boulder County. You could save your map as a web mapping application, or as a storymap, or embed your map in a web page, or use a variety of other ways of communicating your results. A Note about the Data The data for this lesson came from the Boulder County Colorado GIS portal ( Like most county governments, Boulder County realizes that to maximize efficiency, serve its citizens, and reduce costs, GIS is essential to its daily operations and long range plans. Like many though certainly not all counties and cities, Boulder County makes some of its data holdings available to the general public. It does so through its site: Take a look through these layers and see what is available. How did the data from Boulder County end up appearing here in ArcGIS Online? I saved selected data layers from the Boulder County data portal that you examined above, and published those layers as feature services to ArcGIS Online. The reason I did that is because Boulder County does not have their data already in ArcGIS Online nor do they have a streaming data service. It was important to publish the layers as data services so that you can perform analysis on those layers; in other words, if the layers were published to ArcGIS Online as simple zipped shapefiles, then you would not be able to perform analysis on them. You can only perform analysis on layers that are services; these are smart data layers rather than just layers that act as graphics or map notes. Therefore, oftentimes you need to prepare your data, even when working in the online environment, before you can perform analysis on it. Another important note here is that you cannot perform analysis from an ArcGIS Online public account. 14

15 With a public account, you can make and share maps, but you must be using an organizational subscription account to perform analysis. For More Information How to teach with the ArcGIS Platform. Includes basic capabilities, a video on spatial analysis capabilities, step- by- step tutorials, and more: pages/industries/education/higher- education/teach- with- arcgis- platform Deeper Dive with ArcGIS Online video playlist: This is Joseph Kerski s series of video tutorials on ArcGIS Online advanced capabilities: CN 15

16 Appendix: Setting up an ArcGIS Organization Account ArcGIS Online is a web based mapping application made available for the general public s use in developing web maps and applications. ArcGIS Online comes with a free 30 day trial Organizational account, which is what we will use for this course (there is also an option to create an open- ended public account. However, the public account does not share all of the same features/tools as the organizational account). The first part of this exercise will serve to familiarize you with ArcGIS Online and introduce you to the world of web mapping. Follow along with the instructions in order to complete the following goals: 1) Create your own ArcGIS Online account to store your web based maps 2) Learn to add layers, change the symbology, and zoom and pan around your map 3) Save your map for future reference and use Step 1: Sign up for a free 60- day trial of ArcGIS Online. Navigate to Fill in the requested items, and click on the Start Trial button on the main page. 16

17 You will then be shown this message (where it says mail.com it will show the e- mail address you used to register for your ArcGIS Trial). Make sure you use a valid e- mail address that you have access to. ArcGIS will then send you e- mail instructions on how to activate and access your account. Follow along with those instructions now. Your.Name@ .com Once you ve activated your account by clicking on the link in your e- mail, you will be prompted to enter in some additional information. You will need to choose a username and password for your account. Your username can be anything you want. However, use discretion in choosing a username. Names like HotDude123 are not as professional as FirstNameLastName. If you want to be able to share the maps you create and have others view them, choosing an appropriate username is a good first step. Click on the Create My Account button when you ve finished providing the additional information. 17

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19 You are now ready to begin creating your own web- based maps with the help of ArcGIS Online. Step 2: Learn and explore the tools provided by ArcGIS Online Again, navigate to This time click on the Sign In button and enter the credentials you created. 19

20 When you login to ArcGIS Online you will be prompted to Setup Your Organization. ArcGIS for Organizations allows for integration between the organization s GIS servers and desktops that might run an ArcGIS Software package such as ArcGIS Desktop or ArcGIS for Server. Since this course is designed to simply familiarize you with web based mapping, we will just enter in some basic information in order to move on to our next step. You can make up any name you d like for your Organization. In the image below, generic names were used to create our temporary organization. Please, fill out the information below and click on Save & Continue. 20

21 Now that we ve created our user account and provided some information about our organization, it is time to begin exploring the map functionality of ArcGIS Online. You will next be greeted with a Welcome screen. We will learn more about this functionality later. For now, we will explore the various tool bars available to us. Please click on the Map button: When we first navigate to our Map we are shown a map of the world. You are now ready to make your own, customized map. 21