The Elk River Watershed Map is an online geographic information system for the Elk River and its tributaries in Southwest Missouri, Eastern Oklahoma, and Northwestern Arkansas.  The map is provided as an aid for public education and discussion of issues concerning water quality protection and environmental improvement in the Elk River Watershed.
StatusThe initial version of the map is complete and online for November, 2007. The initial map consists of base map layers (topography, air photos, roads, streams, etc.) and includes new Missouri Department of Transportation road center lines for the recently completed US 71 highway and adjacent modified roads.
The map also displays the watershed boundaries for the Elk River and it's tributaries. The watershed boundaries are based on the USGS Hydrologic Unit Code (HUC) watershed classification system. The map includes a preliminary version (still under review) of the 12 digit (HUC12) hydrologic units for the Elk River Watershed. For more information on the HUC classification of the Elk River Watershed, see the watershed data section below.
Data to be added in 2008 includes:
Map InterfaceThe map interface consists of four main components: the map display frame, the theme layer menu, the data list frame. and the map control panel,
Map Display FrameWhen the map is launched, the map display frame will automatically adjust to your screen resolution and browser size and display the start-up default theme layers. The map will restart and resize itself if you change your screen resolution or browser size after it is started. For best results, set your screen resolution to 1024 x 768 or higher and maximize your browser to fill the screen before you start the map.
Theme Layer MenuThe theme layer menu presents a list of map layers that allow specific themes of geographic and environmental information to be accessed. Check boxes at the left of the layer names may be clicked to turn the visibility on or off. Yellow indicates the visibility is on. When the name of a layer is clicked, the panel for that layer will be highlighted in a lighter shade of green and that theme's features will become active for selection on the map. When a layer is selected to be active, its features will also be listed in the data list frame. When a feature belonging to the active theme is selected on the map or from the list, it will be highlighted or marked on the map and it will be marked as the current selected feature on the list.
The image on the right shows a portion of the theme layer menu. It shows that the visibility is turned on for the "Roads" and "Watersheds" layers, and the "Roads" layer is also highlighted to be the active layer.
Data List FrameThe active theme's features are listed in the data list frame. The list may contain feature names, such as road names, or other associated attributes such as the section number or township and range numbers for a selected land survey section.
When a feature belonging to the active theme is selected, it will be marked as the current selected feature on the data list frame and highlighted on the map. The list may be used to select features by name and see their locations on the map.
The listed features are often grouped into categories. The image on the right shows a portion of the list for the "Roads" theme. For this theme, roads are grouped by state, then by city or county to separate roads that occur in different places, but have the same name. The example shows that State Highway 340 in Bella Vista, Arkansas has been selected and only the portion of highway stretching across the city limits of Bella Vista is highlighted on the map as shown in the image below.
When the map is re-centered or zoomed in or out, the feature list for the active theme will change to list only the features shown on the map.
Some themes will also display other associated data when a feature is selected. When stream segments are selected from the "Streams" theme, the stream's name, its reach number, watershed name, and sub-watershed hydrologic unit name are displayed at the top of the list. When the "Location Info" theme is selected to be active, a list of attributes associated with the selected locations are displayed instead of a list of features.
Control PanelThe map control panel has three components: the zoom level control, the map function control, and the location display panel.
Zoom Level Control
The zoom level control, as shown on the right, displays nine zoom level indicators. The green indicator shows the level the map is at. The text display shows the distance across the map for the zoom level. Clicking the indicator level bars will zoom the map directly to the selected level. The arrow buttons zoom the map in or out one step at a time. The left arrow zooms the map out and the right arrow zooms the map in.
Map Function Control
The map function control consists of four buttons and a text display as shown on the right. The text display indicates the action to be taken for the selected button. The text display will also describe the action for each of the buttons as you mouse over them. The text display will flash "Processing Map" when the map is regenerating. The results displayed when the control is set to "Select" mode will vary depending on which layer is active on the layer menu. The selected feature for the active layer will be highlighted and related information will be shown for the selected feature in the data list frame.
Location Display Panel
The location display panel shows the section, township, and range, and the latitude and longitude of the location marker. The location marker is the red dot that highlights points when a point theme, such as "Geographic Points", is active. When themes other than point themes are active, the location marker appears as a red cross in the center of the map and it marks the last location that was clicked when zooming or re-centering the map. When the "Location Info" theme is active, the marker will move to locations clicked on the map without re-centering the map and the location display panel will show the location information for the clicked locations.
Map DataThis section is currently under development.