viewshed analysis of fort ord public lands

Viewshed Analysis of Fort Ord Public Lands using ESRI ArcMap 10 Surface Analyst:

Viewshed Analysis of Fort Ord Public Lands using ESRI ArcMap 10 Surface Analyst Project by Nathanial Wigington , Biological Science Technician, BLM Monterey Peninsula College, MAST10 May 2011

Project Objective:

Project Objective The objective is to create multiple “ viewshed ” analyses of high-traffic roads and trails located within Fort Ord Public Lands to determine the percent area viewable to the public. Analyses will be used to establish the “visual landscape” of Fort Ord as a basic resource, in order to maximize visitor’s scenic satisfaction. Maps produced could be used to help resource managers better manage and perpetuate the visual qualities of Fort Ord Public Lands.

What is a Viewshed Analysis?:

What is a Viewshed Analysis? In GIS, its an analysis that determines the areas of land cover visible to the human eye from a fixed vantage point. Refers to line of sight, so this concept also hold true for radar, cell phone reception, etc. http://www.innovativegis.com/basis/MapAnalysis/Topic15/Topic15_files/image021.png http:// www.lurj.org/vol1n1/tsunami-fig4.jpg

Fort Ord Public Lands:

Fort Ord Public Lands http:// en.wikipedia.org/wiki/File:Fort_ord.gif Projection : California_Teale_Albers (NAD83) Datum : NAD 1983 Created by : Nathanial Wigington Date : May 2011

History of Fort Ord Public Lands:

History of Fort Ord Public Lands Fort Ord , located on California’s Monterey Peninsula coast, was a U.S. Army post from 1917 to 1994. In 1997, the Bureau of Land Management, agreed to manage and protect 7,200 acres of Fort Ord , which is some of the last undeveloped natural wildlands on the Monterey Peninsula. http://di2.shoppingshadow.com/images/pi/eb/07/41/2001223311-149x149-0-0__2001223311.jpg Picture by: Nathanial Wigington http:// farm5.static.flickr.com/4017/4564038920_45aa81a850.jpg

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86 miles of trails for hikers, bikers, and equestrians to publicly enjoy. 35 species of rare plants and animals, and rare maritime chaparral habitat. some species endemic to Fort Ord. Why is Fort Ord Public Lands so special?

What you need for analysis?:

What you need for analysis? Digital Elevation Models (DEM) in raster form. DEM obtained from USGS Seamless Map Viewer (1 arc-sec, 30m resolution). Datum: GCS_North_American_1983 Raster was clipped to fit the extent of the Fort Ord boundary. A hillshade analysis was performed on Fort Ord DEM for 3D visual of topology. Shapefile that contains a point or line feature that will be the observation point(s). Shapefiles were obtained from BLM Fort Ord roads and trails GIS data. Data was projected to that of the DEM raster. All GIS data used for analysis was projected to GCS_North_American_1983.

Data Sources:

Data Sources U.S. Geological Survey (USGS). 1 Arc Sec National Elevation Dataset. SDE raster digital data. National Elevation Data (NED). 2009. Sioux Falls, SD. http://seamless.usgs.gov / Bureau of Land Management. DOI. Hollister Field Office, CA. Created by: David Moore (Resource/GIS Specialist). Bicycle Equestrian Trail Assistance (BETA). BETA Cyclist/Equestrian/ Hiker Observation Report 2010. http://www.ftordbeta.org/statComb2010.php

The Fort Ord boundary was traced from the FO_Roads_Trails layer using ArcEditor Trace toolbar.:

The Fort Ord boundary was traced from the FO_Roads_Trails layer using ArcEditor Trace toolbar. Map Created by: Nathanial Wigington

Create observation point(s) by creating a new shapefile in ArcCatalog.:

Create observation point(s) by creating a new shapefile in ArcCatalog . Set the coordinate system to that of the DEM Raster. To allow the observation points to contain 3D data and provide a more realistic analysis, check the box allowing Z values

High-Traffic Roads/Trails Chosen for Viewshed Analysis:

High-Traffic Roads/Trails Chosen for Viewshed Analysis Barloy Canyon Road ( BCR ) Engineer Canyon Road ( ECR ) Eucalyptus Road ( EUC ) Gigling Road ( GGR ) Hennekens Ranch Road ( HRR ) Jacks Road ( JKR ) Oilwell Road ( OWR ) Old Reservation Road ( ORR ) Toro Creek Road ( TCR ) Trail 01 ( T01 ) Trail 31 ( T31 ) Watkins Gate Road ( WGR ) * Roads/Trails chosen from BETA 2010 Trail O bservation Report. http://www.ftordbeta.org/statComb2010.php

Used ArcEditor to “trace” the high-traffic roads and trails from Fort Ord data features.:

Used ArcEditor to “trace” the high-traffic roads and trails from Fort Ord data features.

Open “Viewshed” toolbar located in ArcToolbox Spatial Analyst:

Open “ Viewshed ” toolbar located in ArcToolbox Spatial Analyst

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The file being analyzed, in this case the DEM Raster file. The file containing the observation point(s). You can specify the file name and location of the output raster or just create it temporarily. Conversion factor (if necessary) between x,y units and vertical units. The curvature of the earth can also be incorporated into the viewshed analysis. Coefficient of the refraction of visible light in air.

Each viewshed analysis was reclassified using the 3D Analyst - Raster Reclass – Reclassify tool.:

Each viewshed analysis was reclassified using the 3D Analyst - Raster Reclass – Reclassify tool. The VALUE field was used to reclassify the viewshed attribute table by assigning the “0” values to 0 and the “other values” to 1 ( No Data = No Data ) The purpose of reclassifying was to calculate percent area of each individual viewshed .

Total Viewshed Analysis of FOPL along high-traffic roads/trails.:

Total Viewshed Analysis of FOPL along high-traffic roads/trails.

Results of Total and Mean % area of viewshed analysis within the Fort Ord Public Lands study area.:

Results of Total and Mean % area of viewshed analysis within the Fort Ord Public Lands study area.

Challenges encountered during Viewshed Analysis:

Challenges encountered during Viewshed Analysis Keep in mind that the “ v iewshed analysis” is based upon the ground elevation and does not consider obstructions such as trees and buildings! To include those factors, a more complex viewshed analysis is needed by adding parameters to the observation point(s) or DEM raster. Had trouble finding and adding vegetation height class of the study area to them DEM, due to different pixel types. Challenge in merging multiple viewshed raster files into one raster dataset for use in statistical analysis (more time needed to explore Raster Toolbar function). Confused as to where tree height data needed to be added within shapefile attribute table in order to conduct a complex viewshed analysis ( OffsetA , OffsetB ). Some error in the roads and trails chosen is inherent based on when and how often particular routes BETA chosen were patrolled. Photo by: Nathanial Wigington http:// www.lurj.org/vol1n1/tsunami-fig4.jpg

Conclusion:

Conclusion Based on the results of the total viewshed analysis, 84.75% of Fort Ord Public Lands is viewable to the public from multiple high-traffic observation points. The analysis only included areas that BLM currently manages; southwest portion of Fort Ord currently managed by the Army – not accessible to the public. Ultimately, it will be incorporated into a “Scenic Quality Management Plan” in order to protect and preserve the beauty and accessibility of Fort Ord and its landscape, while providing for future sustainable growth and development. Private, public, state, and governmental agencies would participate in the Development of the “scenic quality” management plan. Maps from Fort Ord Base Realignment and Closure (BRAC) and Fort Ord Reuse Authority (FOR A) would be incorporated in the managing of development within Fort Ord’s surrounding border lands. FORA: http:// www.basereuse.org/reuseplan/Maps/MapsMain.htm BRAC: http://www.fortordcleanup.com/proptytrans/reusemaps.asp

Special Thanks To…:

Special Thanks To… Arlene Guest, Professor. Monterey Peninsula College. MAST10: GIS/GPS Class . Hollister Field Office, BLM field managers and staff. http://www.blm.gov/ca/st/en/fo/hollister.html Bicycle Equestrian Trail Assistance (BETA). http://ftordbeta.org/ Ford Ord Reuse Authority (FORA). http://www.basereuse.org/reuseplan/HomePage/HomePage.htm Monterey Offroad Cycling Association (MORCA). http://www.morcamtb.org / Base Realignment and Closure - Fort Ord (BRAC). http://www.fortordcleanup.com / Shareholders : BLM, Department of Army, BETA, FORA, BRAC, MORCA, local development agencies, any interested parties.

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http:// www.ijc.org/rel/boards/wqb/hb_fig1.gif