Section 1.0: Auto site tool

1.0.1 Introduction

The BAGIS auto site tool uses a spatial algorithm to suggest the optimal placement of a snotel or snow course site within an AOI. The tool selects a site location that is distant from the area represented by existing sites specified in Scenario 1 of the Site Scenario Analysis Tool while optionally meeting a series of constraints that is selected by the analyst. The constraints can include falling within a elevation or precipitation range, being located within a given distance of a feature such as a river or road, or having desired characteristics like aspect, slope, or ground cover.

1.0.2 Finding an Auto site location

The Auto site tool is accessible from the Site Scenarios tool. After an AOI is specified in BAGIS, the Site Scenarios tool is available from the Analysis and Maps menu. The auto site button is located halfway down the Site Scenarios form in the SiteTools button grouping and looks like this:

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BAGIS will suggest a name for the auto site but this can be overwritten with a name selected by the analyst. The name should be unique within the current AOI. To add a constraint, click the checkbox to activate the associated section. The elevation and precipitation constraints use the DEM and precipitation layers associated with the current AOI.

The Proximity constraint lists any feature layers that exist in the layers.gdb folder of the current AOI. Similarly, the Location constraint lists any discrete raster layers that are present in the layers.gdb folder of the current AOI. A discrete raster only permits integer values with no decimal places. The Location constraint also lists several zone layers, such as Aspect and Slope, that are generated by the BAGIS maps tool. Analysts should use the BAGIS AOI Utilities form to add a new feature or discrete raster layer to the AOI if they wish to use it as an auto site constraint.

To add a Proximity constraint, click the Add button in the Proximity section. This will bring up a sub-menu where you can select the proximity layer and specify a buffer distance. Point and line feature classes require a buffer distance. Click Save when you have finished configuring the Proximity constraint. When you have added all desired Proximity constraints, click the Done button. Details of the Proximity constraints you added should be visible in the Proximity layer list.

To add a Location constraint, click the Add button in the Location section. When you click on a layer name on the left-hand side, the available values will appear in another list. Click on the values you wish to be included in the auto site selection area. That is, value of the raster at the auto site location must be one of the selected values. Use the Save button to configure each layer and the Done button when you are finished. Details of the Location constraints you added should be visible in the Location layer list.

When you have added all the desired constraints, click the Find Site button to run the auto site tool. The auto site tool will pop-up the message below when it has completed successfully.

Note that the new auto site has been automatically added to the list of sites in Scenario 1 on the Scenario Sites form. You will need to click the Clear button to restore the auto site window to its default state trying to create a new, unique site.

1.0.3 Viewing the log for an auto-site

The auto site log button is accessible from the Site Scenarios tool. After an AOI is specified in BAGIS, the Site Scenarios tool is accessible from the Analysis and Maps menu. The auto site log button is located halfway down the Site Scenarios form in the SiteTools button grouping, next to the auto site button and looks like this:

To view the log for an auto site, select the site from the Scenario 1 list of sites in the Site Selection tool and click the Log button. BAGIS will pop-up the auto-site form displaying all of the settings used to generate that site. The '3. Define a new site with the same settings' button should be enabled. This allows the analyst to generate a new auto-site with the same constraint settings but a different name.

If the auto site selected was the most recently generated auto site, the maps button will be enabled so that you can view the map. If BAGIS cannot display the log, it will show an error message. The most likely cause of being unable to display an auto site is that the site selected is not an auto site.

1.0.4 Viewing the map for an auto-site

The Map button on the auto-site form can be used to view a map of the current auto-site in ArcMap. The button is only enabled immediately after an auto-site is generated or if you use the log button to view details of the most recent auto-site created during the ArcMap session. See a sample auto-site map below:

1.0.5 Adding multiple sites iteratively with the same search criteria

To add multiple sites, start by adding the first site with the appropriate search constraints. See section 1.0.2 for details. After the first site has been located, click the ‘2. Add new site to scenario 1 and recalculate’ button to recalculate the represented area so that it includes your new site. When the calculation completes, use the '3. Define a new site with the same settings’ button to populate the form for the next site. This button will prompt you for the new site name and then generate the new site. Keep alternating between buttons 2 (Recalculate) and 3 (Define a new site) until you have the desired number of auto sites or BAGIS cannot successfully find a location for the new site.