How to: Use a custom data source for multiple AOI(s)

Introduction

Most users in the US can use BAGIS-P with the US GIS database (i.e., the data bin) that was compiled for BAGIS-P. However, BAGIS-P was developed as a framework for generating HRU parameters for hydrological models. The framework allows users to use their own data layers and models to compute parameters. This document describes the steps to bring a custom dataset into BAGIS-P.

A parameter is an HRU attribute with which accurate hydrological modeling can be performed. BAGIS-P interfaces with geoprocessing models created in ArcGIS ModelBuilder to estimate the parameter values that are required in certain hydrological models (e.g., PRMS). Most of the geoprocessing models need specific GIS data layers as input. For example, the pct_imperv (i.e., percentage of impervious surface in HRUs) parameter is based on an input impervious layer that can be located by the geoprocessing model. The data requirements are specified in the geoprocessing models. The way the model specifying a data requirement should not prevent the model from being used in a different geographic area or from using an alternative input layer. To achieve this flexibility objective, BAGIS-P uses geoprocessing model parameters and data settings information to make models independent from data. During run-time, BAGIS-P extracts the data setting information and feeds the correctly defined data layers to models through model parameters. If users want to use a different layer as input, they only need to modify the settings files associated with individual AOIs. The geoprocessing models can be reused by different AOIs without needing any modification.

When users want to create their own geoprocessing model to estimate parameters that have not been defined, they must know the input data requirements of the model first. Then, they create the model in ArcGIS ModelBuilder and expose the required data variables as model parameters. At the same time, the users need to define the input layers in the settings file if the layers have not been defined. The next step is to create a BAGIS-P method that links the geoprocessing model with the data layer definitions. The method is later added to a parameterization profile that can be applied on an AOI. During parameterization, BAGIS-P connects data to models. The steps of the process is described in the following sections. Here is an overview of the steps.

• 1. Create a geoprocessing model in ArcGIS ModelBuilder, make sure the input data layers are exposed as model parameters.

  2. Define the sources of the input data layers. If the user already has a target AOI to which the model will be applied, he or she can do Step 4 before Step 3.

  3. Create a parameter method that define link the geoprocessing model with the input data layers.

  4. Clip the input data layers to AOI. Alternatively, all data layers associated with a parameter profile will be automatically clipped to the AOI when the profile is applied to the AOI (step 6).

  5. Add the method to a profile.

  6. Apply the profile to an AOI.

BAGIS-P data source name: Veg_Cover

Model parameter name: db_landfire_evt

AOI name: ochoco_FGDB

1. Begin by creating a model in ArcGIS ModelBuilder that generates the desired parameters. This topic is covered in another document. A custom data source should be added to the model as an input parameter with a special name. The name of the input data source parameter must start with 'db_'. For the purposes of this document, the parameter name is 'db_landfire_evt'.

2. After saving the model, open the Data Manager from the BAGIS-P menu. Use the 'Add' button to add a data source that can be clipped and used by any local profile (AOI).

3. Use the 'Select' button on the Data Source Editor dialog to select a GIS layer from the file system. BAGIS-P will interrogate the layer and populate the list of data fields. Select the field to be used in your analysis.

Name and description are free-form. For the purposes of this document, the name is 'Veg_Cover'

4. Return to the Data Manager after applying your changes. Highlight the data source you just added and click the 'Clip selected layer(s) to AOI button'.

Select the AOI(s) that will be using this data in their parameter calculations. When the 'Apply' button is clicked, the custom data source will be clipped to each AOI. This clipped data will be saved as a local data source in the AOI.

5. Close the BAGIS-P Data manager and open the AOI Parameterization Data manager. Verify that your custom data source is listed. It will have the same name, description, and field as the original data source. Only that path will be different.

6. Close the AOI Parameterization Data manager. Open the AOI Parameterization Profile Builder and select the AOI of interest. After the AOI has loaded, use the 'New' button in the Method section to create a method for your model.

7. Use the 'Select model' button to select the model from step 1. Several fields on the Method editor will populate from the model. Note that the input parameter name is listed as a model parameter on the right-hand side of the form.

8. The list of data sources is derived from the Data Manager (step 5). Select a data source for each 'db_' model input parameter.

9. After applying saving the new method, it can be assigned to a profile using the 'Add' button under the Methods grid.

10. After your method has been linked to a profile, BAGIS-P is ready to calculate the parameters for an HRU layer in the AOI.