This study focuses on lands in an urban-wildland intermix region of the East Bay Hills. The site is 54.3 square miles and forms a rectangle approximately 3.25 miles wide by 16.72 miles long which follows the regional ridge line from Lake Chabot in the south to Wildcat Canyon in the north of the East Bay Hills.
The model was formed by combining spatial data and other information into a composite map. The data gathering for this study was organized into several discrete operations. Some of the data already existed in digital form and some in paper form. Other data were gathered through field work which were either
transferred directly to the data base from a field computer or digitized later in a computer laboratory. Each day maps were generated showing the region sampled and pointing to areas within that region where more sample points were needed to complete the data set. Areas inaccessible by vehicle were sampled in a helicopter equipped with a GPS unit
Several data sets are generated in digital form as Digital Line Graphs (DLG) from the United States Geological Survey (USGS) at a scale of 1:24,000. Hypsography and hydrography along with Digital Elevation Model (DEM) data are combined to construct a surface or digital terrain model to satisfy the topographical needs of the wildland modeling. These data were assembled to form a set of surface sample points (x, y, z coordinates) which represented samples of elevation in the study site. The Delauney Triangulation, commonly referred to as a Triangulated Irregular Network (TIN), is used to create the surface in Figure 3. Information on slope gradient and aspect are obtained from this surface model. Supporting data obtained from the USGS-DLG were used to construct the road layer. This layer was updated and refined using a combination of aerial photography and field surveys where a Trimble Navigation Global Positioning System (GPS) was used for accurate positioning. Two GPS receivers were used, one a base station and the other a mobile receiver mounted on an automobile. Differential GPS was employed and error was corrected to obtain accuracy to within 2 meters.
Click here to see East Bay Hills Relief.
The wildland vegetation layer was delineated using aerial photographs and images obtained from a NASA low altitude data gathering flight in August of 1993. Homogeneous patches of vegetation were registered, digitized and then visited in the field for identification. The time required for field visits was considerably reduced and the locational accuracy greatly enhanced with the use of the GPS units. The wildland fire hazard data dictionary was loaded into the memory of the GPS unit which then allowed patch identification to be easily recorded along with the positional information as the observer moved through the vegetation patch. At the end of each day the data were downloaded from the mobile GPS unit and differentially corrected with data from the GPS base station. After this locational correction, the data were loaded directly to the GIS and the vegetation layer updated. The time savings obtained from this process made it possible for each vegetation polygon in the wildlands to be visited and identified. The GPS units also served as navigation aids for the human observers as they moved through the wildlands.
A combination of road data, images from the NASA low altitude flight, and data obtained from the local
utility company, East Bay Municipal Utilities District (EBMUD), provided the necessary information to
delineate residential areas. EBMUD provided a digital map series of utility drawings which had been
scanned and vectorized. Although these maps were edge matched, they were not in any map projection
nor were they georeferenced. The road layer was used to correctly position the EBMUD data. From this,
information on water service location proved valuable in modeling the potential location of houses. The
results of this strategy were then checked with aerial photographs and block data obtained from the US
Census, to obtain an accurate delineation of the residential region. The fire hazard classification scheme applied in the residential region could not use the scheme developed for the wildlands. Observed patches of vegetation in the wildlands, where natural processes of succession and invasion apply, tended to be homogenous. In contrast, urban-wildland nexus areas, which are predominantly occupied and dominated by humans, appear to be more heterogeneous with a great variety of structural as well as vegetation conditions. These conditions are not necessarily bounded by political interests or physical barriers, such as streets. As a result, the residential regions are not delineated as polygons and then classified, but rather, observations are taken at point locations distributed throughout the study site and later synthesized into a data layer. The conditions observed were not based on an individual property or structure, but on the characteristics of a neighbourhood. The observer evaluated groups of structures to establish the sample neighbourhood of similar attributes.
To understand how the model was constructed, it is helpful to view the varying information sources in isolation prior to seeing the model which combines them.
To properly view the model, you must use ARCVIEW. In order to maximize ArcView's performance, we recommend that you copy all of the data onto your hard drive without changing directory structure and/or names of the folders/directories. Please make sure that you are copying the appropriate version for this model for your operating system (Macintosh or PC) or for ArcView 1.0 or ArcView 2.1. You may also view the model as a static graphic by clicking the map's name in Arcview 2's Map & Data Table.
| Arcview 2 Map & Data Table | ||||||
|---|---|---|---|---|---|---|
| Map | Project (.apr) | Contents | Arcview 2 Data (.shp) | Attribute Table (.dbf) | Legend (.avl) | Data Source |
| Aspect | aspectx.apr | Aspect Streams/Lakes Roads | aspect.shp hydro.shp roads.shp | aspect.dbf hydro.dbf roads.dbf | aspect.avl hydro.avl mjroads.avl | USGS_DLG USGS_DLG USGS_DLG |
| Hypsography | hypsox.apr | Elevation Streams/Lakes Roads | hypso.shp hydro.shp roads.shp | hypso.dbf hydro.dbf roads.dbf | hypso.avl hydro.avl mjroads.avl | USGS_DLG USGS_DLG USGS_DLG |
| Infrastructure | infrastx.apr | Roads/Trails Powerlines BART | roadsall.shp powerli.shp bart.shp | roadsall.dbf powerli.dbf bart.dbf | roadsall.avl powerli.avl bart.avl | USGS_DLG USGS_DLG USGS_DLG |
| Population Density | popdensx.apr | Population Density Streams/Lakes Roads | groups.shp hydro.shp roads.shp | groups.dbf hydro.dbf roads.dbf | popdens.avl hydro.avl mjroads.avl | TIGER USGS_DLG USGS_DLG |
| Residential Fire Hazard (Structural Fire Hazard) | resifhzx.apr | Structural Fire Hazard Wildland Fire Hazard Streams/Lakes Roads | residfhz.shp vegwild.shp hydro.shp roads.shp | residfhz.dbf vegwild.dbf hydro.dbf roads.dbf | struvar.avl wldlmh.avl hydro.avl mjroads.avl | GPS RS_GPS USGS_DLG USGS_DLG |
| Residential Fire Hazard (Vegetation Fire Hazard) | resifhzx.apr | Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Roads | residfhz.shp vegwild.shp hydro.shp roads.shp | residfhz.dbf vegwild.dbf hydro.dbf roads.dbf | vegevar.avl wldlmh.avl hydro.avl mjroads.avl | GPS RS_GPS USGS_DLG USGS_DLG |
| Residential Fire Hazard (Structural+Vegetation Fire Hazard) | resifhzx.apr | Structural+Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Roads | residfhz.shp vegwild.shp hydro.shp roads.shp | residfhz.dbf vegwild.dbf hydro.dbf roads.dbf | totavar.avl wldlmh.avl hydro.avl mjroads.avl | GPS RS_GPS USGS_DLG USGS_DLG |
| Soils | soilx.apr | Soils Streams/Lakes Roads | soils.shp hydro.shp roads.shp | soils.dbf hydro.dbf roads.dbf | soils.avl hydro.avl mjroads.avl | USDA_SCS USGS_DLG USGS_DLG |
| Slope | slopex.apr | Slope Streams/Lakes Roads | slope.shp hydro.shp roads.shp | slope.dbf hydro.dbf roads.dbf | slope.avl hydro.avl mjroads.avl | USGS_DLG USGS_DLG USGS_DLG |
| Wildland Vegetation | vegwildx.apr | Wildland Vegetation Streams/Lakes Roads | vegwild.shp hydro.shp roads.shp | vegwild.dbf hydro.dbf roads.dbf | vegwild.avl hydro.avl mjroads.avl | RS_GPS USGS_DLG USGS_DLG |
| Wildland Fire Hazard | vegwildx.apr | Wildland Fire Hazard (Trees) (Shrubs) (Grassland) Streams/Lakes Roads | vegwild.shp hydro.shp roads.shp | vegwild.dbf hydro.dbf roads.dbf | treehz.avl shrubz..avl grasshz.avl hydro.avl mjroads.avl | RS_GPS USGS_DLG USGS_DLG |
| Location Query (Structural Fire Hazard) | qrstrhzx.apr | Structural Fire Hazard Wildland Fire Hazard Streams/Lakes Streets | residfhz.shp vegwild.shp hydro.shp streets.shp | residfhz.dbf vegwild.dbf hydro.dbf streets.dbf | struvar.avl wldlmh.avl hydro.avl streets.avl | GPS RS_GPS USGS_DLG TIGER |
| Location Query (Vegetation Fire Hazard) | qrveghzx.apr | Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Streets | residfhz.shp vegwild.shp hydro.shp streets.shp | residfhz.dbf vegwild.dbf hydro.dbf streets.dbf | vegevar.avl wldlmh.avl hydro.avl streets.avl | GPS RS_GPS USGS_DLG TIGER |
| Location Query (Structural+Vegetation Fire Hazard) | qrtothzx.apr | Structural+Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Streets | residfhz.shp vegwild.shp hydro.shp streets.shp | residfhz.dbf vegwild.dbf hydro.dbf streets.dbf | totavar.avl wldlmh.avl hydro.avl streets.avl | GPS RS_GPS USGS_DLG TIGER |
| Arcview 1 Map & Data Table | ||||||
| Map | View (.av) | Contents | Arcview 1 Data (coverage) | Data Source | ||
| Aspect | aspect.av | Aspect Streams/Lakes Roads | aspect hydro roads | USGS_DLG USGS_DLG USGS_DLG | ||
| Hypsography | hypso.av | Elevation Streams/Lakes Roads | hypso hydro roads | USGS_DLG USGS_DLG USGS_DLG | ||
| Infrastructure | infras.av | Roads/Trails Powerlines BART | roads powerli bart | USGS_DLG USGS_DLG USGS_DLG | ||
| Residential Fire Hazard (Structural Fire Hazard) | resstrhz.av | Structural Fire Hazard Wildland Fire Hazard Streams/Lakes Roads | residfhz vegwild hydro roads | GPS RS_GPS USGS_DLG USGS_DLG | ||
| Residential Fire Hazard (Vegetation Fire Hazard) | resveghz.av | Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Roads | residfhz vegwild hydro roads | GPS RS_GPS USGS_DLG USGS_DLG | ||
| Residential Fire Hazard (Structural+Vegetation Fire Hazard) | restothz.av | Structural+Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Roads | residfhz vegwild hydro roads | GPS RS_GPS USGS_DLG USGS_DLG | ||
| Soils | soils.av | Soils Streams/Lakes Roads | soils hydro roads | USDA_SCS USGS_DLG USGS_DLG | ||
| Slope | slope.av | Slope Streams/Lakes Roads | slope hydro roads | USGS_DLG USGS_DLG USGS_DLG | ||
| Wildland Vegetation | vegwild.av | Wildland Vegetation Streams/Lakes Roads | vegwild hydro roads | RS_GPS USGS_DLG USGS_DLG | ||
| Wildland Fire Hazard | vegwldhz.av | Wildland Fire Hazard Streams/Lakes Roads | vegwild hydro roads | RS_GPS USGS_DLG USGS_DLG | ||
| Location Query (Structural Fire Hazard) | qrstrhz.av | Structural Fire Hazard Wildland Fire Hazard Streams/Lakes Streets | residfhz vegwild hydro streets | GPS RS_GPS USGS_DLG TIGER | ||
| Location Query (Vegetation Fire Hazard) | qrveghz.av | Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Streets | residfhz vegwild hydro streets | GPS RS_GPS USGS_DLG TIGER | ||
| Location Query (Structural+Vegetation Fire Hazard) | qrtothz.av | Structural+Vegetation Fire Hazard Wildland Fire Hazard Streams/Lakes Streets | residfhz vegwild hydro streets | GPS RS_GPS USGS_DLG TIGER |
(USGS_DLG: U.S. Geological Survey Digital Line Graph)
(USDA_SCS: U.S. Department of Argriculture Soil Conservation Service)
(TIGER: U.S. Census Bureau TIGER/Line Files)
(GPS: Differential Correction Geopositioning)
(RS_GPS: Remote Sensing and Differential Correction Geopositioning)
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