National Water Information System: Mapper

NWIS HOME | MAPPER

How To Use the Mapper

This interface provides a map view of the locations of sites with USGS water data. The interface can be used most efficiently by following a few basic rules:
  1. Center and zoom to area of interest.
  2. Select site types using checkboxes.
  3. Sites are clickable only when zoomed in enough for accurate selection.
  4. Specific areas such as USA states and territories can be selected using the drop-down list.
  5. Named places and addresses can be selected using geographic searching.

Selecting Sites to Include

Selecting Status of Sites to Include
Surface-water sites
Groundwater sites
Springs
Atmospheric sites
Other sites
    The National Water Information System (NWIS) provides access to data at over 1.5 million sites. There are 56 possible site types used in the NWIS data base, including 14 primary types and 42 secondary types. To simplify mapping of the site locations for most practical applications, the site types are displayed in 5 groups that include the following primary and secondary types. The full list of site types can be found here.
Active Sites
Inactive Sites
    Sites may be active or inactive. A site is considered active if: (1) it has collected time-series (automated) data within the last 183 days (6 months), or (2) it has collected discrete (manually collected) data within 397 days (13 months). If it does not meet these criteria, it is considered inactive. Some exceptions apply. For example, a site may also be shown as active if it is part of an ongoing occasional data-collection program. If a site is flagged by a USGS water science center as discontinued, it will show as inactive regardless of how recent data may be. A USGS science center can also flag a new site as active even if it has not collected any data. This control allows a user to select a broad category of sites to view, and is useful for simplifying a view in areas with a high density of sites. The default selection is Active sites.

Any data
Instantaneous data
Daily data
Water-quality data
Peak data
Measurements
Annual report
    At any given site, one or more types of data may be available. Where data collection is continuous, data may be available in real-time, as individual observations, or as daily summaries. Some sites may have data from water-quality samples. At stream sites, data may be available for flood peaks. For surface-water and groundwater sites, data may be available for individual field measurements. For many active or recently active sites, there may also be an online annual summary report. The default selection is any data. These selections are only active when sites are clickable.

Selecting an Area or Place to View

Selecting Status of Sites to Include
Selecting an Area or Place to View
   

The Mapper provides several alternatives to selecting an area to view. The Navigation Controls explained below can be used to select areas directly on the map. The default selection is the lower-48 USA states.

The Search tab on the left panel provides several Map Search options for views based on a named location or major watershed.

Search by Place

Search by address
Search by placename
   

This option selects an area using a street address or place name, and is useful for viewing close to a specific point of interest. The preferred method can be specified using the drop-down menu. Searching by place name (e.g. Fargo, ND) is most effective when a specific address is not available, and will create a viewing extent that brackets the named place. Searching by street address will usually result is a closer view, and will create a view that is centered on the address. Either search will also accept just a Zip Code.

Search by Site Number(s)

Search by site number
   

This option selects an area using one or more site numbers. If one number is entered the view will be centered on that site. If more than one number is entered, separated by commas, the view will use the spatial range of the sites to determine the view.

Search by State or Territory

Search by state or territory
   

This option selects a particular U.S. State or territory by name from a list, and is useful for quickly viewing a larger area. The map view will be centered on the area and include at least all area inside its official boundaries.

Search by Watershed Regions

Search by watershed region
   

This option selects a major watershed region by name from a list, and is useful for quickly viewing a larger area. The map view will be centered on the area and include at least all area inside its official boundaries.

Displaying Sites

Explanation below is for zoom levels in which sites are not clickable.
Surface‑Water Sites
Active site
Inactive site
Groundwater Sites
Active site
Inactive site
Spring Sites
Active site
Inactive site
Atmospheric Sites
Active site
Inactive site
Other Sites
Active site
Inactive site
  Explanation below is for zoom levels in which sites are clickable.
Surface‑Water Sites
    Active site
    Inactive site
    Multiple sites
Groundwater Sites
    Active site
    Inactive site
    Multiple sites
Spring Sites
    Active site
    Inactive site
    Multiple sites
Atmospheric Sites
    Active site
    Inactive site
    Multiple sites
Other Sites
    Active site
    Inactive site
    Multiple sites
 

The Mapper displays clickable sites only at smaller scales in the map view (zoom level 10 or greater for groundwater sites and zoom level 8 or greater for all other site types). This approach provides a reasonably fast drawing time. The display of each of the site types and corresponding available data types can be turned on and off using the checkboxes and radio buttons. Multiple site types can be displayed concurrently, but only one data type per site type group can be displayed at a time.

Shapes and colors are also used to indicate the type of data collected at sites. Black triangles and gray colors represent surface-water sites, black dots and red colors represent groundwater sites, black dots with a tail and purple colors represent springs, black diamonds and blue colors represent atmospheric sites, and open circles and green colors represent all other site types.

At some locations there are multiple sites. These are indicated by a Multiple Sites mapping symbol.

The full explanation of symbols for a site type will only appear when that site type tab is selected.

Selecting a Site and Getting Data

   

Controls in this section only apply at zoom levels where sites are clickable.

Selecting (clicking) the site will identify it by site number and name. A link is also provided to access any available data from the National Water Information System. Multiple links are provided in cases where there are multiple sites at one location.

 

Viewing a List of Displayed Sites

A list of all sites that are shown in the map view is available in the the information panel below the map. The panel can be viewed by clicking on or made hidden from view by clicking on . The list can be exported in several formats, and includes links to access any available data from the National Water Information System.

The information panel has tabs that provide two principal functions. The first function is provided by the Status tab (example shown below) lists the five site type groups by active and inactive status.

For each group and active/inactive status, the following information is listed with respect to the current map view:

Important: The information presented in the information panels can be sorted by clicking on the column heading. For example, to sort the information in alphabetical order by Site Name, click on that column heading. If you click on the heading again, the column will be sorted in reverse order.

The second function lists the sites. A tab is provided for each of the five site group types, with sub-tabs for active and inactive status. An example for the Surface Water site type group and active status is shown below.

For each site shown on the current map view, the following information is listed:

Selecting (clicking) any row in the Site Group tabs will highlight that site on the map.

 

Exporting Site List

Export site information
   

Site information can be exported in the following formats listed below. The Table of Sites will be displayed directly in the web broswer, and all other formats are exported as a zipped data package that contains three files: (1) Readme.txt, which describes the contents of the data package, (2) Metadata.txt, which provides the specifications for the retrieval, such as creation date, time, bounding coordinates, and other information about the map view, (3) NWISMapperExport.nnn, which is the actual list of sites in the requested export format, where nnn is the file type suffix listed below.

  • Table of Sites (.html) - Display in a web browser
  • List of Site Numbers (.txt) - File can be used as input for a data retrieval at waterdata.usgs.gov
  • Microsoft Excel (.xls) - Spreadsheet
  • Comma Separated (.csv) - Spreadsheet or data base compatible
  • Tab Separated (.rdb) - Spreadsheet or data base compatible
  • Keyhole Markup Language (.kml) - Open using Google Earth or compatible map software
  • ESRI ShapeFile (.shp) - Open using ArcGIS or compatible GIS software

Map Layers - Background Views

Map tab

Map Layers

Map layers
Watershed Boundary Dataset
  Watershed Boundary Dataset line symbol USGS National Hydrography
  Dataset (NHD)
  NHD Home Page
Principal Aquifers
  USA Principal Aquifers
  USGS National Atlas
  National Atlas Home Page
USGS Offices
  USGS Water Scence Center Office Water Scence Center
  USGS Water Field Office Water Field Office
   

Several additional layers of information are available to complement the display of sites using the Map Layers selection under the Map Layers tab. Note that map layer views are appropriate to and will vary with map scale.

Base Maps

Base maps
    The default background view is an ESRI Streets map. Several background map types are available and can be selected using the Base Maps selection under the Map Tools tab. More information on each base map is available at ESRI Map Services, or by selecting the link on the left to particular base maps. All uses of ESRI base maps are subject to their Terms of Use. Note that background views are appropriate to and will vary with map scale. Not all views are available at all scales, particularly when zoomed in very close to a location.

Navigating in ESRI Maps

You can navigate (move your view) in two dimensions in any ESRI Map. To pan (move the map), do one of the following: Additionally, you can zoom in or out by moving the cursor over a location and using the mouse scroll button to zoom in or out on that location. To center and zoom in on a location, you can also double click on the location.

 

Using the Navigation Controls

Navigation controls

On-screen zoom controls are shown on the left. Zoom controls include:

  1. Zoom level indicator- Zoom level ranges from 1 to 19. Level 4 approximates a view of the lower-48 USA states. Groundwater sites are clickable at level 10 and above, and other sites types are clickable at level 8 and above.
  2. Zoom - Click to zoom in on the center of the map. Click to zoom out.
  3. Zoom slider - Drag the zoom slider up or down to zoom in or out incrementally.

Additional controls are described below and are provided to set the function of the cursor and to select map views.

Navigation controls bar
Zoom in box Zoom In - Sets the cursor for zoom-in operation using 2 corners of a box. The cursor is clicked at one corner of a box and released at the opposite corner for the area to be zoomed.
Zoom out box Zoom Out - Sets the cursor for zoom-out operation using 2 corners of a box. The cursor is clicked at one corner of a box and released at the opposite corner. The amount of zooming out will depend on the size of the box, where a large box will zoom out less and a small box will zoom out more. Note that using this control takes some practice!
Pan Pan - Sets the cursor for pan operation. The map extent will move with the cursor at a fixed zoom level.
Previous view in stack Previous View - When selected the map will go back to the previous view in a stack, if one has been created.
Initial view Initial View - When selected the map will go to the initial view when the browser was opened.
Next view in stack Next View - When selected the map will go ahead to the next view in a stack, if one has been created.
Refresh drawing Refresh - When selected the map will be redrawn using current search settings.

Map Tools

Scale bar, longitude, latitude

Scale Bar

The scale bar shows a graphic map scale for estimating distances. The scale bar is shown using line weights and colors that can be read easily on most base maps, including the default. In some cases, the scale bar may be easier to distinguish on an alternative base map, particularly one with a lighter color.

Longitude and Latitude Coordinates

The longitude and latitude of the cursor position are shown in decimal degrees. Note that when obtaining the coordinates of a data site the map symbol, including its shadow, is centered over the exact coordinates of the data site -- at zoom levels of 15 or more, there is no discernable difference in coordinate values at any point on the map symbol. The coordinates are shown using a font weight and color that can be read easily on most base maps, including the default. In some cases, the coordinates may be easier to distinguish on an alternative base map, particularly one with a darker color.

 

Using the Overview Map

Overview map  

The overview map (shown left here) appears in the bottom right corner of the map. It helps to orient you by showing the location of current map view in the context of a larger geographical area. The area currently displayed in the map is show as a purple box in the overview map. At any time, click Hide overview button to hide the overview map or click Show overview 
       map button to display it again.

As you pan or zoom in the map, the overview map view changes accordingly. You can change the existing view in the map by doing one of the following:

  • Drag and drop the purple box in the overview map.
  • Drag and drop the area outside the purple box to pan the map.

Parameters in the Web Page Address (URL)

Certain parameters can be included in the web page address (URL) to create opening views that go directly to an area of interest. These include U.S. state or territory codes, center coordinates, and zoom level. To include a parameter in the URL, append the following to the URL after a "?" for the first parameter, and an "&" for additional parameters. For example, to create a view centered on the lower 48 states, the full URL would be:
https://maps.waterdata.usgs.gov/mapper/index.html?MapCenterX=-96.0&MapCenterY=36.0&MapZoom=4. The types of sites and activity status to be included in the opening view can also be included in the URL. Sites types are joined into five general groups for mapping: Surface Water (sw), Groundwater (gw), Springs (sp), Atmospheric (at), and Other (ot). The Active or Inactive status of sites must also be specified with the site group. If both parameters are not included, no sites will be included in the opening view. The site group and status can be specified in the URL in the same way as the geographic parameters. For example, to create a view of active groundwater sites, the full URL would be:
https://maps.waterdata.usgs.gov/mapper/index.html?SiteGroups=gw,act.

where:

The Overview Map is turned on by default, but can also be turned off in the opening view using a URL parameter. To specify that the Overview Map will not be shown in the opening view, the full URL would be:
https://maps.waterdata.usgs.gov/mapper/index.html?OverviewMap=no.

where: