CURRENT TOOLS

Solar Analyst - An ArcView® GIS extension for modeling solar radiation

How the Solar Analyst Works

The Solar Analyst works within ArcView® to generate upward-looking hemispherical viewsheds, in essence producing the equivalent of a hemispherical (fisheye) photograph for every location on a digital elevation model (DEM). The hemispherical viewsheds are used to calculate the insolation for each location and to produce accurate insolation maps. The Solar Analyst can calculate insolation integrated for any time period. It accounts for site latitude and elevation, surface orientation, shadows cast by surrounding topography, daily and seasonal shifts in solar angle, and atmospheric attenuation. The Solar Analyst offers similar features to TopoView, but runs as an ArcView extension.

Features

• Broad accessibility: based in ArcView®; does not require expensive, high–end GIS software;
  
• User friendly: user interface implemented using ArcView Dialog Designer and ArcView Avenue; benefits from ArcView's mapping, query, graphing, and statistics functions
  
• Versatile output: calculates direct, diffuse, & global radiation; direct radiation duration, skyview factor; sunmaps and skymaps; and viewsheds
  
• Simple input: requires only DEM, atmospheric transmittivity, and diffuse proportion (latter two parameters calculated from nearby weather stations or using typical values)
  
• Flexibility:
  
  • calculates insolation for any specified period (instantaneous, daily, monthly, weekly …)
    
  • calculates insolation for any region (whole DEM, restricted areas, or point locations)
    
  • allows specification of receiving surface orientation (from DEM, field survey, or orientations of surfaces such as sensors or leaves) and height offsets for ground features
    
• Fast and accurate calculations: uses advanced viewshed algorithm for calculations; accounts for viewshed (sky obstruction by near–ground features), surface orientation, elevation, and atmospheric conditions; calculation engine implemented in C++ library format and dynamically loaded
  
• Programmable: adds new object–orientated components, including new classes and instance requests, to ArcView Avenue; improves user efficiency by allowing task automation; permits development of custom models (e.g., energy balance and water balance models) by programming the Solar Analyst along with Avenue or other model libraries.

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Most Similar Neighbor Analysis

The Most Similar Neighbor Analysis tool set is designed to create landscape current vegetation data for all polygons in a project area with enough data that the entire landscape can be grown to project no action and treated future conditions.

In the past data preparation for MSN analysis has been an obstacle to its use. INFORMS has included several tools that streamline data preparation.

The implementation of the MSN in INFORMS brings together several elements that make the data preparation for MSN much easier and standardize the process for each Forest Vegetation Simulator - Variant.

One of the difficulties a user of the MSN applications often had even if data preparation is possible is determining which variables to be used in the MSN processing. Many variables will provide little or no value in imputing the best stands. The INFORMS team has worked with the researchers who developed MSN to develop the best set of variables for each variant and include them in the INFORMS application. INFORMS automatically grows the available stands to the year of the landsat scene used as part of the data set and automatically picks the correct MSN command file based on the variant used to grow the stands.

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Fire and Fuels Analysis Packages

INFORMS currently is used mostly to support the NEPA process, particularly for Fuels Reduction projects. The application uses data from the FSVeg database grown forward using the Forest Vegetation Simulator, including the Fire and Fuels Extension (FVS/FFE) for the current condition and each decade into the future up to 40 years for no treatment alternatives. It is also possible to create as many treatment alternatives as desired. These can also be portrayed for the same growth periods to compare difference between treatment and no treatment and between alternative treatments.

These alternatives are created with the FVS application and the ability to define changes in vegetation by modeling the treatment.

Tools within INFORMS produce several valuable products:

• Product 1 - generates a map for each time period we call the burn model, which is a matrix of torching index (a wind at what speed will be required to cause a ground fire to torch trees in the stand) and the crowning index (a wind speed that will be required to sustain a crown fire). The matrix of these two values generated by FVS/FFE is displayed as 5 classes of burn intensity. This creates a map for each forested stand polygon displayed in light to dark shades of red, the darker the more intense.
  This map is useful several purposes in fuels reduction project planning. These include the ability to visualize the areas of greatest concern for possible treatment and there relationship to other areas of concern. The maps give us the ability to compare analysis areas such as watersheds to determine which is in the highest priority for treatment. These maps are also quite useful in public communication to help the public understand the condition of areas they may live near or have concerns about.
  
• Product 2 - the creation of FARSITE ready data. FARSITE is a fire simulation application that models fire spread and intensity under user defined conditions. These layers are created for current and future conditions. The primary use of FARSITE in project planning is to run a simulated fire through an analysis area with and without treatment to evaluate the effects of your proposed treatments. FARSITE can be used to optimize various treatments, these FARSITE runs can also be very good tools to communicate with the public.
  
• Product 3 - used in conjunction with INFORMS is the Stand Visualization System (SVS). INFORMS creates files that show how a stand will burn with or without treatment. This is quite useful for id team and public discussion of effects. This part of the application is not yet as automated as we would like but the basic data is prepared but the user still needs to set up the fire simulation at a specific time. The more automated method to accomplish this is under development.

These tools are described in more detail in the Fire Tools section, which highlights new tools being developed and enhanced for use with fuels and other NEPA analysis.

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