Cat Schooley - Technical Skill Assessment

Without step by step instructions on how to perform specific tasks, my ability to emulating a work environment and troubleshoot as well as my overall knowledge of data analysis processes was put to the test. The data I worked with was from a tool called BRAT (Beaver Restoration Assessment Tool). It was made by the ET-AL Lab at USU and came from the Bear lake watershed.

Section 1: Vectors

Task A: Total Length of Stream Network (NHD_24k_300mReaches.shp)

1. Open attribute table

2. Right click field you are interested in calculating, in this case ‘StreamLen’, and choose ‘Calculate Geometry’

WARNING: This action CANNOT be undone if you calculate outside of an edit session

3. Choose which shapefile you are interested in calculating, then the target field, what property (length), length unit (kilometers) and the appropriate coordinate system (projected coordinate system of the shapefile).

4. After the field has been calculated, right click on it again and choose ‘Statistics’, this will create a statistics summary for that field including mean, median, standard deviation, etc. We are interested in sum.

What is the total length (in kilometers) of this stream network?

The total for the stream length is 4180.867 km.

Task C: Determining Coordinate System (Provisional_ValleyBottom_Unedited.shp)

1. After loading the shapefile into ArcGIS Pro, right-click on the shapefile in the ‘Table of Contents’ pane and choose ‘Properties’

2. Click ‘Source’ and then scroll down until you see ‘Spatial Reference’ and click the down arrow there

3. This shapefile has both a ‘Projected’ and ‘Geographic’ coordinate system

a. Projected Coordinate System: coordinate systems that are localized to minimize visual distortion in a particular region, units are meters, kilometers, miles etc.

b. Geographic Coordinate System: coordinate systems that span the entire globe, units are in longitude and latitude

Note: All coordinate systems except the ‘Geographic Grid’ are based on some sort of 3-D projection and that is what we are seeing here

What is the coordinate system of this shapefile? Is it a projected or geographic coordinate system?

This coordinate system for this shapefile is the projected coordinate system ‘NAD 1983 Idaho TM (Meters)’, but this projected coordinate system is based on the geographic one, NAD 1983.

Task D: Determining Rows in a Shapefile (Idaho_BearLake_16010201_BeaverDams.shp):

1. Right-click on the shapefile and choose ‘Attribute Table’

2. At the bottom you will notice where it tells you how many rows (how many points) are in this shapefile

3. Being a point shapefile, this tells me how many points there are, if it were a polyline shapefile it would tell you how many line segments, polygon how polygons.

Note: You must be careful in doing this in case of duplicates

How many dams (points) are in this shapefile?

The total points for this shapefile is 72 points.

Section 2: Raster

Task A: Finding Unique Values (LANDFIRE_EVT_merge.tif)

1. Right-click on the raster file after you have added it to the map and choose ‘Symbology’

2. Choose ‘Unique Values’ from the first drop down

3. From the second drop down choose the field you are interested in (CLASSNAME)

4. From here you can choose a color scheme or set your own colors for each value

5. At the top you will see how many unique values you have

How many different classes (CLASSNAME) of land are there in this raster?

There are 123 different land classes.

Task C: Understanding Raster Units (Slope.tif)

1. Slope can be calculated as ‘degree of slope’ or ‘percent of slope’

a. Degree of Slope: the angle of the slope

b. Percent of Slope: calculated by the dividing the rise by the run of the point and then multiplying that by 100 (also known as the percent rise)

i. If the rise is greater than the run ((100/10)*100) then the percent rise would be 1000%, therefore any steep slopes would be quite high in value

Note: Slope is typically ran on an elevation dataset with an output in degrees

2. The fact that the values for this raster are less than 90 and the common way of calculating slope leads me to believe the units are in degrees

What are the units on this raster? What does a value of 45 mean?

The units are in degrees and a value of 45 would mean that the degree of slope is 45 degrees

Task D: Find Resolution (NED_DEM_10m_16010201.tif)

1. After adding the raster file to the map, right-click it in the ‘Table of Contents’

2. In ‘Properties’, click ‘Source’

3. The cell size tells you the resolution, and the vertical units tells you what units it is in

What is the resolution of this DEM (in meters)?

The resolution for this DEM in 9m.

Section 3: Attributes

Task A: Calculating Field Statistics (Data_Validation_Perennial.shp)

1. Open the attribute table of your shapefile

2. Right-click on the field of interest (iGeo_Slope for this example)

3. Click ‘Statistics’ and review the ‘mean’ value there

What is the mean slope (iGeo_Slope) of the entire network?

The mean slope of the entire network is 0.0305

Task B: Selection by Attributes using SQL expression (Data_Validation_Perennial.shp)

1. Right-click the shapefile and choose ‘Attribute Table’

2. Click ‘Select by Attribute’

a. This will open a ‘Select by Attribute’ dialog box

3. Within this box, choose which file you want to select from and then the type of selection (new selection for this example)

Note: Here you can create a new selection, add to current selection, remove from current selection, etc.

4. Then using a SQL query, you choose a field as a parameter (occ_Ex for this example) and then a condition (greater than for this example) and then a value for that condition (10 in this case)

Note: The value doesn’t have to be a number, it could be a name, letters within a name, etc. It depends on what type of field you are using in the query (string, integer, etc.). This field type also determines the kind of conditions you can use (starts with for string fields, greater than for numeric fields, etc.)

5. You can hit either ‘Apply’ or ‘OK’. ‘Apply’ will just make the selection without closing the dialog where as hitting ‘OK’ will make the selection and close the dialog.

6. Viewing the attribute table, the amount selected out of the total will be shown in the bottom left

How many reaches (each row is a reach) have an expected beaver dam capacity (occ_EX) over 10?

There are 2855 reaches that have an expected beaver dam capacity over 10.

Task D: Select by Attribute (Data_Validation_Perennial.shp)

1. Right-click the shapefile and choose ‘Attribute Table’

2. Click ‘Select by Attribute’

a. This will open a ‘Select by Attribute’ dialog box

3. Within this box, choose which file you want to select from and then the type of selection (new selection for this example)

Note: Here you can create a new selection, add to current selection, remove from current selection, etc.

4. Then using a SQL query, you choose a field as a parameter (Stream Name for this example) and then a condition (not equal to for this example) and then a value for that condition (‘blank’ in this case)

5. You can hit either ‘Apply’ or ‘OK’. ‘Apply’ will just make the selection without closing the dialog where as hitting ‘OK’ will make the selection and close the dialog.

6. Viewing the attribute table, the amount selected out of the total will be shown in the bottom left

7. To find the percentage I hand calculated it by dividing the selected by the total (2915/7003)

What percentage of reaches have a stream name (StreamName)?

The percentage of reaches that have a stream name is 41.6%.

Section 4: Comprehensive

Task B: Selecting by Location & Attribute and Calculating Geometry (Data_Validation_Perennial.shp & NationalSurfaceManagementAgency.shp)

1. Knowing that I would want kilometers as my final measurement I calculated geometry for the ReachLen on kilometers

2. Open up the attribute table for NationalSurfaceManagementAgency shapefile and use ‘Select by Attribute’ to set a SQL query to select those that are owned by the United States Forest Service (USFS)

a. Where ‘ADMIN_AGEN’ ‘is equal to’ ‘USFS’

3. Looking in the attribute table you will see how many polygons have been selected.

4. On the ‘Map’ tab in ArcGIS Pro, click ‘Select by Location’

Note: ‘Select by Location’ will only use the rows (polygons) already selected in its SQL query

5. Select your input features as the Data_Validation_Perennial shapefile because we are interested in the reaches within USFS agency land

6. Select ‘Within’ as your relationship because we want those reaches that are within USFS land that we can work on building dams

7. Select ‘New Selection’ as your selection type

8. Use ‘Select by Attribute’ to select the reaches from the Data_Validation_Perrenial shapefile that are possible to build a dam on

a. Input Rows: Data_Validation_Perrenial

b. Selection type: ‘Select subset from the current selection’

i. We want the reaches from our current selection of reaches within USFS land

c. Where ‘oPBRC_UD’ ‘is equal to’ ‘Dam Building Possible’

9. Now that we have the reaches within USFS land and dam building possible selected we can calculate the total length

10. Open the attribute table for the Data_Validation_Perrenial shapefile and right-click on the ‘ReachLen’ field and click ‘Summarize’

a. Select your input table as the one containing your selected reaches (Data_Validation_Perrenial)

b. Select your field to ReachLen and statistic type to Su

Note: This provides a summary of only the selected features and exports them to a new output table that you can name whatever you like.

11. Open the new table and view the result

What is the total length of reaches that are within USFS land and on which dam building is possible (oPBRC_UD)?

The total length of reaches within USFS land and on which dam building is possible is 261.041052 km.

Task C: Raster Selection and Statistics (Slope.tif & Idaho_BearLake_16010201_BeaverDams.shp)

1. Input the beaver dam data and the slope raster dataset into the map

2. Use the ‘Buffer’ tool to make a 20m buffer around each beaver dam point

Note: After this step I found two different ways to do this and it yielded the same result for the mean so I will go through both.

Method 1: Zonal Statistics: calculates statistics on values in a raster within the zones of another

1. Open the ‘Zonal Statistics’ tool

2. Set your Feature Zone Data to your beaver buffer shapefile

3. Set your zone field to the ObjectID of the buffer shapefile

4. Set the input value raster to your slope raster dataset

5. Choose a raster output

6. Set your statistics type to the mean because that is what we are interested in

Method 2: Extract by Mask: extracts the cells of a raster defined by a mask

1. Open the ‘Extract by Mask’ tool

2. Set your input raster to your slope raster

3. Set your feature mask to your buffer shapefile

4. Create a raster output file

For either method the final steps are the same.

1. Right click your output raster dataset and choose ‘Properties’

2. Click on the ‘Source’ tab

3. Under ‘Statistics’ view the minimum, maximum, and mean

What is the average slope of areas within 20m of a Beaver Dam?

The mean slope of areas within 20m of a Beaver Dam is 5.35 degrees.

Task D: Select by Location (NHD_24k_300mReaches.shp & tl_2018_roads.shp)

1. Use ‘Select by Location’

2. Set your Input Features to the roads shapefile because we are interested in what roads intersect with streams, not which streams intersect with roads

3. Set the Relationship to ‘Intersect’

4. Set the Selecting Features to the reach shapefile

5. Set Selection Type to ‘New Selection’

6. The number selected in the bottom left of the roads attribute table tells us how many roads there are

How many roads intersect the stream network? (For this question, each row counts as a road)

There are 1291 roads that intersect the stream network.