Program in GIS

Final Suitable Sites for Vineyards in Napa Valley, California

Figure 1: Suitable Sites for Vineyards.

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 1 shows the suitable sites for vineyards (approximate 1295 acres) that takes into account the need to be located with specific flood, land use, aspect, wind, temperature, soil depth and soil drain characteristics.

Figure 2: Suitable site showing whether site is on public or private land.

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 2 shows suitable vineyard sites by public and private land.  Adding the "private land" criteria removed approximately 556 acres of suitable sites from the total.  Thus, there are approximately 739 suitable acres that meet the criteria on private land.

Creating this map required:

• Converting vector data to raster format

• Creating a hillshade theme from an elevation grid—see Figure 3

• creating an aspect theme from an elevation grid—see Figure 4

• Interpolating grids from a series of sample points—see Figures 5 and 6

• Creating buffer zones around raster features

• Reclassifying grid cell values for the purpose of grouping features

• Performing criteria-based analysis by combining multiple grid themes—see Figure 7

  • Outside of floodplain or stream buffer

  • Agriculture or undeveloped land

  • SE, S, SW, W, or NW orientation

  • Average maximum wind speed less than 25 mph

  • Average minimum temperature greater than 35 degrees F

  • Soil depth between 31-72 inches

  • Medium to highly drained soils

• Finding suitable sites that are not on public lands (optional)—see Figure 2

How This Analysis Could Be Improved With Higher Resolution Data

Higher resolution data would improved the analysis by removing ambiguity due to interpolation.  The climate and soils data are spot points, which, if the number of spot data were increased, would allow for much more detail in the wind speed, temperature, soil depth, and soil drainage data.  Thus, we might be able to determine with greater accuracy potential vineyard locations that would otherwise be missed and potential non-useable areas that are currently included.

Higher resolution terrain data, likewise, would give a more detailed description of the landscape and would improve analysis relative to determining aspect.  Given, however, the large-scale needs for vineyards, I don't think additional resolution would be much help (e.g., finding a small area that would need to be accessed, irrigated, etc. would most likely not be worth an investment).  Finding or eliminating small pockets of land probably wouldn't do much in the way of making a better decision from the analysis.  Humans will always need to verify that the analysis makes sense in the real-world environment.

Steps Along the Way

Create Hillshade From Elevation Data

Figure 3: Use elevation data (left) to create hillshade (right).

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 3 shows the resulting hillshade layer that gives an impression of depth to the terrain after using Spatial Analyst to generate a hillshade from the elevation data.

Create Aspect From Elevation Data

Figure 4: Use elevation data (left) to create aspect (right)

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 4 shows the aspect (North, East, South, West, etc.) of the terrain after using Spatial Analyst to generate aspect from the elevation data.

Create Maximum Temperature Zones From Climate Data

Figure 5: Use climate data (left) to create temperature zones (right)

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 5 shows the maximum temperature zones (relatively, green is low, to yellow and tan is medium, and white is high) from "spot" climate data after using Spatial Analyst "Interpolate to Raster" capability.

Create Maximum Wind Speed Zones From Climate Data

Figure 6: Use climate data (left) to create wind speed zones (right).

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 6 shows the maximum wind zones (relatively, green is low, to yellow and tan is medium, and white is high) from "spot" climate data after using Spatial Analyst "Interpolate to Raster" capability.

Create Suitable Sites From Criteria Layers

Figure 7: Criteria layers are "raster calculated" to determine suitable sites.

Source:  Brenton White ArcMap Project 7 screen capture.

Figure 7 shows the layers for each criteria with the color indicating zones that meet the criteria.  These layers are "raster calculated" to generate the resulting Suitable Sites.  The raster calculation simply multiplies each layer with a color being 1 and no color being 0, thus the suitable sites are only where each cell had a color in all the criteria layers.

GEOG 5222: Project 7: Delineating Vineyards. May 2004.

Lesson 7 file.  http://www.e-education.psu.edu/courses/geog5222/zips/exp7files.zip.  Accessed 31 May 2004.