Online Geospatial Data Sources

NOAA NowCoast Weather – IMS 9 February 2009

Introduction

NOAA’s NowCoast web site (http://nowcoast.noaa.gov) has some very useful time-sensitive weather data. The data is available in ArcIMS Web Map Services, and can therefore be readily consumed by ESRI GIS software clients, but not so much by other geospatial tools. NOAA notes on the website that they have plans to create an OGC-compliant Web Map Service (WMS) as well as Web Feature Service (WFS) sometime in federal fiscal year 2008 (FY08); however, as of the review of the website by this author (8 Feb 2009), none was available.

Figure 1. NowCoast Webpage Initial Display - screen shot.

The NowCoast web map service includes many data layers and sources (too many to mention in entirety here). The service includes current weather station data, forecasts, and radar and satellite weather imagery. Weather station data includes current weather variables from Airports, Coastal-Marine Automated Network (C-MAN) Stations, NWS buoys, Gulf of Maine Ocean Observing System (GoMOOS) buoys, and NOS’ Physical Oceanographic Real-Time System (PORTS)… more acronyms than you can shake a stick at. Weather forecasts are linked from the web map service (with URLs) to various forecast web pages on the National Weather Service website (http://www.weather.gov) for County forecasts, Regional forecasts, and Marine forecasts.

Data Listing (partial)

• Current Observations
  • Air Temperature
  • Dew Point Temp
  • Wind Speed/Direction
    

    Figure 2. NowCoast example of available weather station data for New England Area.

  • Atmospheric Pressure
  • Visibility
  • Sea Surface Temp
  • Wave Height
  • Weather Radar images (NEXRAD)
  • GOES Visible and Infrared Cloud Cover images

• National Digitial Forecast Database (NDFD) (Gridded data for CONUS-only)
  • Temperature, MIN/MAX  (12 hour - 96 hour forecasts)
  • Relative Humidy (3-78 hrs)
  • Surface Wind Speed (3-78 hrs)
  • Wave Height (12-84 hrs)
  • Precipitation Amount (6-66 hrs)
  • Wind Speed/Vectors (3-78 hrs)

• Web “Weather” Cams
• Clickable links to various weather forecasts (Regional, Marine, Off-shore Marine)
• NWS Weather Alerts (short-fuse alerts and some long-fuse alerts)

Access

Access is open to the public. Instructions on connecting to the ArcIMS Image Service can be found on the NowCoast website by using the “Map Services” link at the top of the initial NowCoast webpage. The process for accessing is pretty straight-forward, and includes using the following URL (ttp://nowcoast.noaa.gov), and selecting the “NowCoast” service from the web map service listing in your application of choice.  

• Service Type: ArcIMS Image Service
• Server Address: http://nowcoast.noaa.gov/
• Service Name: nowcoast

Usability

The image service has many data layers and as a result is complex to use, although it is not beyond the ability of an experienced GIS professional. I have provided screen captures of some of the data from the NowCoast web map service using ArcGIS Explorer and ArcGIS Desktop (see figures 3 and 4). 

Figure 4. NowCoast web map service as initially displays in ArcGIS Desktop.

Figure 3. NowCoast Airport Weather Data displayed in ArcGIS Explorer.

Data Quality

Most of the data available is of good quality. Exceptions included the Web Cams layer, of which many of the links are broken, and the Weather Radar (NEXRAD) images, which are unfiltered for ground clutter. Better NEXRAD images are available from other web map services and web sites including some universities and commercial sources. 

Update Frequency 

Update interval varies, but is fairly frequent for much of the available data. As a case in point, the weather radar images (NEXRAD) have an update frequency of from 4-10 minutes (depending on the radar site supplying the data).

Metadata

Complete metadata does not seem to be available, but NOAA does provide what may be a more useful descriptive web page for each layer of data in the web map service. 

Ratings

Accessibility Rating: Fair

Usability Rating: Fair

Data Quality Rating: Very Good

Overall Rating: Very Good

Ratings on 5-pt scale (1- Poor, 2- Fair, 3- Good, 4- Very Good, 5- Excellent)