C.O.A. Trail Shade Indices

This outline will detail the process of estimating the shade distribution over the trails and will be displayed with a percent shade index for every 1/8th of a mile of trails for the entire city limits of Austin. The general process is to create a buffer around the trail and clip the canopy with it to get the canopy that provides shade over the trail throughout the day. Then color code the trails by length of 1/8th mile of percent coverage. This analysis was performed with most tools from the Geo-processing Tab on the Toolbar and downloaded free software X-Tools for dividing the trails equally.
*NOTE: When creating any NEW FIELD during this analysis, the Double Integer option was always selected for input purposes.
Trail Canopy Coverage for Entire City
1) Begin by adding the CAPCOG City Limits Data. This has the city limit outlines for several cities in various counties of Central Texas.
2) Open the City Limit’s Attribute Table and Select Austin under the City column. Once it is highlighted the entire row, go over the CAPCOG layer and right click, provides an option to ‘Create a Shapefile from Selected’ this will result in a new layer that only contain the city limits of Austin.
* Note: There is an exception in this step, the incorporated cities within the city limits were left out because each has its own source of funding, and the ones left out include: Rolling Wood, Westlake Hills, and Sunset Valley. 
3) Add Trails data provided. (File labeled BIKE_ROUTES)
4) Clip the Trails Layer with the city limits of Austin. This is to exclude any trails that are outside the city limits and to keep the trails that within the boundary. The trails that are in neighboring incorporated cities were excluded will be clipped out and not used for analysis and percentages.
5) Dissolve the Trails Layer to create one entire continuous trail. The original Trails file that was provided by the city has non uniform lengths; some are varying from a few feet to hundreds of feet in distance.
*Note: (Have NO boxes checked- Multipart & Un-split).
6) Use X-tools to divide the Trails equally into 1/8th of a mile. The Trails file is a polyline, the tool will be set to create individual segments at lengths of 660ft which equal 1/8th of a mile. In the Toolbox Tab select the X-Tools option, then in the dropdown menu find Feature Conversion, and within it will be the option to Split a Polyline. The window that appears provides various input options, in the Method section select the Split polyline into specific segments equal to Lengths of 660 feet.
*In the Attribute table, Add a new Field labeled Length, then right click the new column and select the Calculate Geometry option to display the Length.
*A Unique ID is automatically created with splitting the Trails ID is a single number that repeated that represents an entire trail from the original file. Need to create a unique identifier for each individual segment to compare with canopy segments in the following steps. Add new Field and label it Segment-ID, then Field Calculator and select first under Function: Int () and then under Field: FID. This will create a unique ID labeled

*Note: Exception in the lengths all dividing equally, there will be included a Remainder in every segmented trail, this is a result of the trails not equally dividing in 1/8th mile because every trail length is not divisible by 660ft equally. To reduce the amount of remainder between segments we used the dissolve in Step 5 to reduce any previous lengths that would be used to divide trail and split the individual trails at the intersection.
 
Trail Area for Segments with Buffer (THE NON-SHADED AREA)
7) Add a 20ft Buffer to the Segmented Trails. This creates a 20ft radius on both sides of the trail to capture any canopy that provides coverage throughout the day.
*Note Options to select (Side Type: FULL, End Type: FLAT, Dissolve Type: NONE).
*Include Segment Trail Area, Add new Field labeled Segment Area, then Calculate Geometry to display total amount of area buffered per segment (Total amount of Non-Shaded area for analysis).

Tree Canopy Area per Segments of Trails (THE SHADED AREA)
8) Add the Tree Canopy layer.

9) Use the Buffered Trail from (step 7) to CLIP out the canopy that provides shades to the trails. This will result in a layer that only has the available tree canopy coverage areas over the trails throughout the day.
At this point we have the total Un-Shaded split into 1/8th of a mile segments and the clipped canopy over the Trails. Need to divide the canopy coverage areas into the same 1/8th of a mile segments to determine the amount of percent shade.

10) Union is used to separates the canopy into individual trail buffers. In the Union window Input first the Buffer Trails and then the Clipped Canopy. The reverse method will not give the correct output. Next Add a new field and label it Area, then right click new column and select Calculate Geometry option to display the amount of Area per segment.
*Note: Keep GAP checked, it will create a -1 FID for Clipped Canopy
11) In the new Union layer created, Delete the Areas that do not have any canopy coverage which display (Canopy Area = 0). This will result in the Union layer only contain the areas that have shade.
12) Dissolve the canopy into the segmented trails to create continuous canopy divided per segment. In the Union layer that includes the areas that only have canopy coverage (Step 11 results), the canopy is included by individual areas and not a total sum.  This is because the Union divides up the canopy into the 1/8th of a mile segments, but it does not combine all the canopy areas into a single coverage in each individual segment. Use the Dissolve tool and select the canopy coverage areas to Dissolve into the Segment Buffered Trails using the (Seg-ID), this will combine the individual canopy areas per segment into a canopy area per segment.  By using the (Seg-ID) to dissolve the canopy layer, this uses a single identifier to compare the amount of canopy coverage area to trail area.
*Note: Display the amount of canopy in the new layer by opening the Attribute table; create a new Field that is labeled Canopy Area, then Calculate Geometry to display the amount of Area.
 12) Join data from different tables into one to perform analysis. Combine data tables to relate information from the Union layer which has the Canopy Shade Area and the Segmented Buffers layer that includes the Total Non-Shaded Area.
*Note: To transfer data to table where the layer will be displayed, begin by placing the cursor over the layer for the Segment Buffers and right click it to get options. Select Join and add the data from the Union layer by relating with the unique identifier (Seg-ID).
13) To create the Shade Percentage for every segment of Trail, open the Attribute table for the Trails Segment Buffer layer and Add a new Field labeled Percent Shade, then select the Field Calculator to perform the algorithm, use the Fields on the left to calculate:
(Shaded Area / [Non-Shaded Area]) * 100 = Total Percent Shade per Segment of Trail
14) To Display Data,  The final display for the Trails Percent Coverage will be displayed by the color that represents the amount of coverage available per Segmented Buffer. In the Trails Segment Buffer layer where the percentages are located, right click and select the Properties option. Under the tab Symbology, set the display by Quantities on the left tabs. Then set the Value on the drop down menu to Percent Shade and the display as a Graduated Color Scheme, this will illustrate the percent of shade for every segment with appropriate color for coverage.

Canopy Coverage over Trails for Neighborhoods
1) Begin by Adding the Trails, Tree Canopy, and Neighborhoods data.
2) Clip the Trails to the Neighborhoods. This will keep all the Trails within the Neighborhoods and exclude any that fall outside the boundary.
3) Dissolve the Trials within the Neighborhoods to create one long continuous Trail that is contained by the boundary layer. 
4) Create a 20ft Buffer on the Trails. *Note: This analysis is only analyzing the Canopy Coverage over the Trails to create the Shade Percentages within Neighborhoods.
5) Clip out the Tree Canopy areas that are contained within the Buffer.
6) Dissolve the resulting Canopy to the Neighborhoods; this will make it one single canopy layer over the Trails within the Neighborhoods.
*Note: Verify that the ‘MULTI-PART’ box is selected before finalizing task. This will group together the multiple trails that are contained within individual neighborhoods.
Going to use the Union Tool to combine the data and divided up per Neighborhood area for the Trails and Canopy, note that it is important to pay attention in the order in which the layers are entered in the Union window.
Non-Shaded Area
7) Select the Union Tool, first input the continuous Trail and then the Neighborhoods layers. This will result with the Trails being divided up into individual Neighborhoods.
Shaded Area
8) Select the Union Tool, first input the single canopy and then Neighborhoods layers. This will result with the Canopy Coverage being divided up into individual Neighborhoods.
*Note: After performing the Union steps for both the layers there is additional data that needs to be deleted in each output layer the attribute table will contain values of -1 and 0. The results wanted are the 0 values and above because only represents the trails or canopy coverage within individual Neighborhoods. Delete all the -1 values because it includes individual neighborhood boundary and increases the total area which can skew the percentages. To delete the values, open the Editor Toolbar and select the Start Editing option, then select the layer which you want to work on. Highlight all the -1 values and select the highlighted ‘X to delete them, once complete select the Stop Editing option and Save the changes made.

After the unwanted areas have been deleted, the area can be displayed for the amount of Trail and Canopy Coverage area is within each Neighborhoods.
9) Open Attribute Table in the Union Trail layer. Add a new Field and label it (Trail or Non-Shaded Area), then Calculate Geometry to display the corresponding area of Trail per individual Neighborhood.
10) Open Attribute Table in the Union Trail layer. Add a new Field and label it (Canopy or Shaded Area), then Calculate Geometry to display the corresponding area of Canopy Area per each individual Neighborhood.
To make a relationship between Shade and Non-Shaded Areas. Find a unique identifier in the tables in order to do a join. For this study the GIS-ID was assigned as the unique identifier.
11) Join data based on the GIS-ID to have all the data on the same table. Right click on the Neighborhood layer and select Join. Note that the Join will have to be done individually for each Union layers that contain Area. Join the Trails to Neighborhoods and also the Canopy to Neighborhoods. This results in the area information being displayed for both layers in the Neighborhoods Attribute table.
12) To create a Shade Percentage value open the Attribute Table for Neighborhoods and Add a new Field labeled (Percent Shade). Right click the new field and select Field Calculator. To calculate the total percent shade, you have to divide the area of the canopy coverage by the entire area of the trails then multiply by one hundred in order to get a percentage by using field calculator. In the Calculator screen select from the Fields on the left and input the algorithm to determine the percentage:
(Shaded Area/ Non-Shaded Area)* 100 = Total Percent Shade for the Trails within each Neighborhood
13) Cartographic Display. Right Click the layer and select the Properties option. Under the tab of Symbology, select to display by Quantities, under the Value select the Percent Shade and for the color scheme choose graduated colors to display with corresponding trail shade percentage per individual neighborhood.

Creating Canopy Coverage over Trails for Watersheds
1) Begin by Adding the Trails, Tree Canopy, and Watersheds data.
2) Clip the Trails by the Watersheds. This will keep all the Trails within the Watersheds and exclude any that fall outside.
3) Dissolve the Trials within the Watersheds to create one long continuous Trail that is contained by the boundary of the layer. 
4) Create a 20ft Buffer on the Trails.
*Note: This analysis is only analyzing the Canopy Coverage over the Trails to create the Shade Percentages within Watersheds.
5) Clip out the Tree Canopy areas that are contained within the Buffer.
6) Dissolve the resulting Canopy to the Watersheds; this will make it one single canopy layer over the Trails within the Watersheds.
*Note: Verify that the ‘MULTI-PART’ box is selected before finalizing task. This will group together the multiple trails that are contained within individual Watersheds.
Going to use the Union Tool to combine the data and divided up per Watersheds area for the Trails and Canopy, note that it is important to pay attention in the order in which the layers are entered in the Union window.
Non-Shaded Area
7) Select the Union Tool, first input the continuous Trail and then the Watersheds layers. This will result with the Trails being divided up into individual Watersheds.
Shaded Area
8) Select the Union Tool, first input the single canopy and then Watershed layers. This will result with the Canopy Coverage being divided up into individual Watersheds.
*Note: After performing the Union steps for both the layers there is additional data that needs to be deleted in each output layer the attribute table will contain values of -1 and 0. The results wanted are the 0 values and above because only represents the trails or canopy coverage within individual Watersheds. Delete all the -1 values because it includes individual Watersheds boundary and increases the total area which can skew the percentages. To delete the values, open the Editor Toolbar and select the Start Editing option, then select the layer which you want to work on. Highlight all the -1 values and select the highlighted ‘X to delete them, once complete select the Stop Editing option and Save the changes made.

After the unwanted areas have been deleted, the area can be displayed for the amount of Trail and Canopy Coverage area is within each Watersheds.
9) Open Attribute Table in the Union Trail layer. Add a new Field and label it (Trail or Non-Shaded Area), then Calculate Geometry to display the corresponding area of Trail per individual Watersheds.
10) Open Attribute Table in the Union Trail layer. Add a new Field and label it (Canopy or Shaded Area), then Calculate Geometry to display the corresponding area of Canopy Area per each individual Watersheds.
To make a relationship between Shade and Non-Shaded Areas. Find a unique identifier in the tables in order to do a join. For this study FID-Water was assigned as the unique identifier.
11) Join data based on the FID-Water, to have all the data on the same table. Right click on the Watersheds layer and select Join. Note that the Join will have to be done individually for each Union layers that contain Area. Join the Trails to Watersheds and also the Canopy to Watersheds. This results in the area information being displayed for both layers in the Watersheds Attribute table.
12) To create a Shade Percentage value open the Attribute Table for Watersheds and Add a new Field labeled (Percent Shade). Right click the new field and select Field Calculator. In the Field Calculator screen that select from the Fields on the left and input the algorithm to determine the percentage:
(Shaded Area/ Non-Shaded Area)* 100 = Total Percent Shade for the Trails within each Watershed
13) Cartographic Display. Right Click the layer and select the Properties option. Under the tab of Symbology, select to display by Quantities, under the Value select the Percent Shade and for the color scheme choose graduated colors to display with corresponding trail shade percentage per individual Watershed.