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The newly revised Indiana Water Quality Atlas (IWQA) is an on-line mapping application with ArcGIS On-Line functionality. Now, with enhanced water quality data access and download capabilities, the IDEM Office of Water Quality chemistry and aquatic life monitoring data is easier to find and use inside and outside of the application. For a brief overview of the IWQA, the following tutorial should get you started.
Starting in the upper left, you can perform a search, by watershed name, watershed code, city name, town name, unique address, or county, which will zoom into the location requested. There are also Zoom buttons to the left of the Search box to further set the map extent. If either of the watershed search criteria is used, the watershed will display, but only until you click off the the location. To see all of them, the HUCs Layer must be turned on. Once you are zoomed into an area of interest, more layers will become visible.
The top right of the banner bar has additional tools you can use to customize the map. Noted below are the tool descriptions in no particular order. The first one is the Basemap Gallery button.
Several basemap options are provided that include topographic maps, aerial imagery, and other canvas options that will enhance your map. The application starts with a default option already visible, but this is where you can switch it out for another one specific to your needs.
If all you need is a basemap you can decide to save to print at this point. The printing function can be used for saving your map to a specific size and format. Sizes are listed for the final layout or you can opt to print only the map. Format options include PDF, EPS, GIF, JPG, PNG32, PNG8, SVG, and SVGZ.
If you have your own data that you want to add on this map, use the Add Shapefile button. Clicking on this button provides an explanation and the window for adding a zipped (ZIP) shapefile. This allows you the opportunity to view your data along with the provided data, then save a print of the map with your data included.
In the Legend dropdown, the point feature layers under AIMS (Assessment Information Management System) are displayed, as well as line features, such as the Impaired Waters, then the Hydrologic Unit Code (HUC) layers will be shown once these layers are added to the view. Other layers that you may want to be displayed will show up in the Legend once activated in the Layers list. This Legend will be used in your Print to a specific layout Size. However, if you choose to print the map only, the resulting image will not include a legend. Depending on your needs, you may want to do this but take a screen capture of the Legend to add separately in a poster layout or report.
The Layers dropdown provides all of the available datasets that can be displayed (at different scales when necessary for improved performance). A full list of available layers is at the end of this page.
Additional functions that are available to the user to further customize your map and data interface includes enable/disable pop-ups (for most layers), transparency settings, and full access to the attribute data table. Note that if you enable many layer pop-ups, it may hamper return time.
Multiple pop-ups for a clicked area will stack. The number of pop-ups activated on the map will be shown in the top left of the pop-up. There are arrow buttons on the top right to move through the stack to find the layer of interest.
Lastly, layer order can be changed to provide better visualization of the data. At the bottom of the dropdown you will find the link to the layer’s metadata. Click on Description and a new window will open with the metadata.
For access and use of the Water Quality Data collected by the IDEM Office of Water Quality and stored in the AIMS database, there is a link called Show Related Records at the bottom of each popup – see above popup graphic. Below is an example of the data tables section of the screen.
The top bar of the table can be moved up or down to maximize your table viewing area. There is also a close/open tab in the center of the top bar of the table (or bottom of map) for easy access without making a selection on the map. At the top left of the table are tools and tabs of the different datasets within the AIMS database – Chemistry, Fish, and Macroinvertebrate. Depending on the point you selected, you may have only activated two or one, based on the sampling activity that took place at that site.
The additional tools are active when you use the AIMS Table Layers in the Layers List. These are at the bottom of the list and you may need to scroll down the list to see them.
The right dropdown button next to each of them includes an Open Attribute Table option so you can open the entire dataset of each should you want to make a multiple sites selection to export. You can also Filter the records in these tables or make a manual selection with your cursor. The other option in the dropdown is the Description, which is the metadata for each table used in this application.
The Options tools dropdown offers the Export function which can download a CSV file of your selection or all of the data. All of the data includes locational information for you to use in your own GIS applications. You can also create a subset of the AIMS data that you’ve downloaded and zip it, then re-add those subset points to the IWQA. This allows you to turn off the statewide AIMS layers and only have your subset displayed.
The vertical and horizontal scroll bars can help you review the extent of the tabular data based on your screen selection. However, the Option to Show/Hide Columns can help you focus on what you need to know within the screen width. To practice, turn off the Station ID column by clicking on the Show/Hide Columns option and the window of fields will popup up on the right. Turn off the checkmark next to the Station ID and you’ll see the column disappear. These values will not be needed for future reference; the main search value for future reference regarding AIMS data is the Station Name.
Remember when exploring the data points with the table window open, the data will not automatically change to the new site; you need to click on the Show Related Records link to update the table for the new location selection.
L-THIA estimates changes in recharge, runoff, and nonpoint source pollution resulting from past or proposed development. It estimates long-term average annual runoff for land use and soil combinations, based on actual long-term climate data for that area.
To use the Long-Term Hydrologic Impact Analysis (L-THIA) Model tools while in the IWQA, click on the label at the top center of the IWQA title/tool bar. This will launch the L-THIA application in a new window. The direct link (http://lthia.agriculture.purdue.edu/) will open with an interactive map and tools window. There are instructions and other support materials available here on the L-THIA model page.
If you need to delineate your own subwatershed by selecting a specific point along a stream, click on the Delineate tab and use the Point subtab to click on a point on the map. If you have a latitude and longitude, click on the LatLng subtab and fill in the blanks and Submit. The results will show on the map, but you can also download this polygon by clicking on the Tools tab and then the View and Save subtab. There you can Download Shapefile that will return a zipped file with the shapefiles inside. The zipped file is what you will add using the Add Shapefile tool in the IWQA.