GIS2 Lab 7 (Part 3 of 3)

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For Lab 7, I want to help you learn how to: a) visualize and analyze forest damage; b) wrap up the project by checking off all your objectives; and c) build a thoughtful answer to your research question. Advice: Read everything before doing anything so you can visualize your workflow, plan your time, and anticipate what comes next. I also recommend printing this handout and taking notes on it as you work. You will appreciate these notes after you return from breaks. Also, when saving outputs, given them user-friendly names. Feel free to continue using the ArcGIS Project and geodatabase that you used during Lab 5.

ArcGIS Pro / Camp Fire and insert a new layout; call it “Fire Damage Layout”. Before

adding anything to your “Fire Damage Layout”, adjust the properties of your layout. Use a custom 6.5 inches wide by and 6.5 inches tall page size, which will be perfectly wide enough to fit between the page margins of your lab report; no resizing needed.

Next . Leave it empty for now. .

Insert a new map into your project called “Fire Damage Map”.

Next, make sure your extension is checked on (

).

Next, derive and surfaces without adding your DEM as a layer. I want you to see it is possible to run analysis tools by pointing to data in your database and adding only the output to your map; you don’t need to make layers out of everything before setting up and running a tool.

Next, derive a surface for November 19, 2018 @ 3:30 PM, again, without adding your DEM as a layer. Use the U.S. Naval Observatory app for generating solar position tables (USNO, 2015).

Next, your Burn Severity surface as a new layer. The burn severity surface holds four integer values that express the ordinal severity scale described by J.E. Keeley (2009)(Table 1).

Next, you’re going to customize the of your Burn Severity layer. Make your Burn

Severity layer the active layer by highlighting it in your table of contents. Next, change layer

setting from the default “0%” to about “40%.” Next, activate the tool. With the Swipe tool enabled, you can use your mouse to swipe east-west (or north-south) across your map. Swiping allows you to make comparisons between overlapping layers. As you change scale (zoom in/out), pan, and swipe, take time to read the terrain. Compare the burn scars against your Slope and Aspect surfaces. Take notes; especially about the locations or areas where the deepest burning or the least burning occurred.

GIS2 Lab 7 (Part 3 of 3)

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Question 1: What is the apparent relationship between burn severity and terrain steepness and what is the apparent relationship between burn severity and terrain aspect? (Do not describe your map – i.e., left, right, top, or bottom; instead, describe what your map represents - north, south, east, west, named places, high elevations, low elevations, east-facing slopes, gentle slopes, etc.) (2 pts) Table 1. Keeley’s (2009) ordinal severity scale with descriptions and raster coded values.

Burn severity Description Raster value

Unburned The green plant parts (leaves or needles) are still green and unaltered; they exhibit no direct effect from heat.

0

Scorched Unburned, but plants exhibit leaf loss from radiated heat. 1

Light Canopy trees still have leaves or green needles, but scorched stems. Surface litter, mosses, and herbs were charred or consumed. Soil organic layer intact; soil charring limited to < 1 cm.

2

Moderate Trees with some canopy cover killed, but needles were not consumed. All understory plants charred or consumed. Fine dead twigs on soil surface were consumed and logs are charred. Pre-fire soil organic layer was largely consumed.

3

Deep Canopy trees killed and needles consumed. Understory, surface litter of all sizes, and soil organic layer were consumed. White ash deposition to several cm depth.

4

Source: Keeley, J.E. 2009. Fire intensity, fire severity and burn severity: a brief review and suggested usage. International Journal of Wildland Fire Vol.18, p.116–126.

your project.

GIS2 Lab 7 (Part 3 of 3)

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into your project. A global scene view provides the GIS Analyst with 3-D visualization tools.

the Percent Tree Canopy Cover surface as your first layer. Change the color symbol for the “0” percent value from black to “No Color”. After the change, you should notice that all the cells with zero percent canopy cover are now transparent.

If you’re having trouble visualizing the relief, then find your

and increase the setting to “3x” (the default is “1x”). You may recall that we had to exaggerate the elevation axis earlier this semester to help us better visualize the terrain around Crater Lake.

Next, your Burn Severity surface as a new layer.

Spend some time your scene. Pan, zoom, and rotate your scene. Turn layers on and off. Swipe layers on and off. Make and spend time to read your data and to develop a better understanding of how the fire interacted with the terrain. We want to know how deeply (or lightly) the fire burned what where. Question 2: Reconsider your answer to Question 1. What new information did you learn about the relationship between vegetation burn severity and terrain? How did visualizing the terrain in 3-D change your spatial thinking process (compared to just 2-D)? (3 pts)

your project.

GIS2 Lab 7 (Part 3 of 3)

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We want to learn how much of the ground area was deeply burned or moderately burned, because these zones will be vulnerable to landsliding events during future rainstorms. Also, we want to know how much of the tree canopy and understory were completely or moderately burned because these areas will be attractive spaces for invasive species to invade.

Figure 1: Emergency responders worked to establish and maintain a perimeter to prevent the spread of the wildfire. In this image, the fire was consuming both trees and understory plants. Finding the area of ground burned and finding the area of forest burned might seem like difficult quantities to find, but they’re not difficult if you recognize that you already have all the data you need in your geodatabase. We know (or can easily find) the cell size property of each raster, so we can derive cell area pretty easily. We also know that each cell in the burn severity raster belongs completely to one severity category, so all we need to do is count the number of cells that belong to each burn severity zone and calculate the area covered by each zone.

The only problem we have is with the Percent Tree Canopy Cover raster. Actually, we have two problems. First, each cell holds the percent of cell ground covered by trees, and those percentages vary over space and within each burn severity zone. Second, we cannot do any spatial overlay analysis with the burn severity raster and the Percent Tree Canopy Cover raster (yet) because the two grids are not aligned and composed of different sized cells (see Figure 10-2 in Bolstad 2019, p447).

Use to create a new version of your Percent Tree Canopy Cover raster; a new version composed of cells aligned with and sized the same as your projected burn severity raster.

1. Environments > Snap Raster = burn severity 2. Parameters > Input Raster = percentTreeCover 3. Parameters > Output Raster = percentTreeCover_resamp 4. Parameters > Output Cell Size = burn severity 5. Parameters > Resampling Technique = Bilinear

GIS2 Lab 7 (Part 3 of 3)

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Next, use and the method shown below (Eq. 1) to derive TreeArea.

TreeArea = (percentTreeCover_resamp / 100.0) * cellarea Eq. 1

where:

treeArea is the desired output raster with cells holding tree areas measured in sq.m;

percentTreeCover_resamp is the new resampled raster with cells holding percentages [0,1, … ,99,100] that

indicate the percent of ground area covered by tree canopy.

100.0 is the percentage that represents a whole cell. It is used as a constant to convert each input percentage back to a proportion (yes, the zero on the right side of the decimal point is necessary). For example, a cell holding a percentage = 45 will, when divided by 100.0, return the proportion 0.45.

and

cellarea is a constant (sq.m) and can be derived from the raster cell size (m) property of your raster.

Next, use to perform raster overlay analysis. Specifically, you want to compute the SUM all the TreeArea values that occur inside each Burn Severity zone. I strongly encourage you to use the interactive Help [?] window to help you learn how to setup the tool and create the table you need. Read to learn. If you need even more help, then you can check out this video.

your new statistics table as a text file (*.txt) so that you can wrangle with it in Microsoft Excel ®.

Or, if your prefer, use the tool. your project. Question 3a: Create a user-friendly table that highlights the amount of ground area in each burn severity zone. That means reporting areas in sq.km (and sq.mi in parentheses) and indicating, for each zone, the percent of total area. Check your answer to this question against your answer to Q3a in Lab 6 (5 pts) Question 3b: How much of the affected ground area was moderately or deeply burned and, so, is likely vulnerable to erosion processes or landsliding during future storm events? (5 pts) Question 4a: Create a user-friendly table that highlights the amount of affected forest in each burn severity zone. That means reporting areas in sq.km (and sq.mi) and indicating, for each zone, the percent of total forest area. Again, report user-friendly severity class names, not computer-friendly raster codes. (5 pts) Question 4b: How much of the forest was deeply or moderately burned by the fire, so, may be vulnerable to opportunistic pests and invasive species in the coming years? (5 pts)

GIS2 Lab 7 (Part 3 of 3)

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Congratulations, for you’ve accomplished the first five of six objectives! Take a moment to review the evidence you’ve collected over the course of Labs 5, 6 and 7. Your prior lab reports will come in handy. “Question” 5: Use your empty layout to build a reader-friendly figure for your report that highlights some of the evidence you collected while accomplishing either Objective 3, 4 or 5 (one, not all). Show your readers how California’s Camp Fire affected people XOR affected property XOR affected forest. You have complete

creative control. When you’re done, your layout as an image (in *.tif format and with at least 600 d.p.i.). (10 pts) Advice for new cartographers. A good map figure uses data selectively to reveal information and a good map figure has labels that guide the reader’s eye (the content-to-ink ratio is high). A bad map figure uses data to show a pile of data and it looks like a pile of ink (the content-to-ink ratio is low). Some datasets are appropriate to show only at large scales (so zoom way in); others, only at small scales (so zoom way out).

GIS2 Lab 7 (Part 3 of 3)

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Figure 2: The area affected by California’s Camp Fire, which burned from November 8 to November 25, 2018. The maximum perimeter (show above) was reached quickly by November 19th and maintained during the rest of the wildfire event. Burn severity analysis was conducted after the fire was contained. The total area affected by the fire was x sq.km (y sq.mi). The total area that was either moderately or deeply burned was xx sq.km (yy sq.mi), or z% of the total area within the perimeter.

GIS2 Lab 7 (Part 3 of 3)

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Build a well-written report for Lab 7. Include your name, date, and lab title on the first page. Insert page numbers. Your report should be printed on letter size paper. Set all page margins to be 0.7” except for the left margin, which should be set to 1.2.” Use 1.5 line spacing, set the normal font face to be Bookman Antiqua, Bookman Old Style, or Georgia, and set the normal font size to be 11 points. All section headings should be left-justified and in bold. Neither headings nor captions should be orphaned.

Your Purpose and Objectives sections should be written in your own words and must address the purpose and the objectives of the entire project (not just Lab 7).

Your Methods and Data section will explain how you accomplished your work. Use screen captures to help you illustrate the tools you used with your parameter choices.

The Results and Answers section should include answers to the questions or task items posed during the lab. Support your claims with evidence, examples, or supporting tables or figures. Claims not supported by evidence or examples will be considered as just opinions and, so, will be scored accordingly.

Your Summary section is crucial. For this final lab report, you are required to marshal all the evidence you collected during Labs 5, 6 and 7, to sift through that evidence, and to select the best pieces that will help you answer the research question. In other words, do NOT copy-n-paste every answer, every table, and every figure you put in every previous lab report: instead, make choices as you develop and write an evidence-driven story. Remember, you’re the GIS Analyst – you’re the one that’s responsible for converting data into information. You’re the one that’s responsible for interpreting and describing the meaning(s) of your results. If you want to be understood, then write well enough to be understood. (20 pts)

You also want to walk away from GIS2 with tangible proof that you learned new knowledge about the Camp Fire (and GIS), developed new spatial thinking skills AND improved your technical writing capability. Applying a consistent style and formatting throughout your report, proofreading for both accuracy and clarity, and paying attention to the details, are effective ways to achieve a professional-looking result.

As usual, all tables and figures must be numbered, have captions, and be referenced in your text. Table and figure captions should not be orphaned and, when appropriate, should identify units of measure. All tables and figures must be inserted inline with your text (and not slapped onto the back as an attachment). Add a line space above and below each table to buffer them away from your adjacent paragraphs. Table columns that contain text strings ought to be left-justified. Table columns that contain numbers should be right-justified with decimal points aligned (i.e., use the same level of decimal precision). Table records should be sorted in a meaningful way (usually by the column of interest).

Question 6: Take a moment to reflect on our semester, then compare the summary section you just wrote to finish this project against the summary section you wrote to finish Lab 1. Describe any qualitative differences you see in your GIS knowledge, GIS skill set, confidence, or work product. I want to read what you think.

Keeley, J.E. 2009. Fire intensity, fire severity and burn severity: a brief review and suggested usage.

International Journal of Wildland Fire Vol.18, p.116–126.

United States Naval Observatory. 2015. Sun or Moon Altitude/Azimuth Table Application. United States Naval Observatory Astronomical Applications Department. Last accessed on April 28, 2019 at https://aa.usno.navy.mil/data/docs/AltAz.php