Online Geospatial Data Sources

NOAA Interactive Snow and Ice Mapping System – IMS 3 March 2009

Introduction

Since the Nation’s Capital was hit with a late Winter snow yesterday (2 March 2009), I was thinking about snow cover and available online sources mapping extent and depth of snow cover. The NOAA Snow and Ice Mapping System has daily updates on snow and ice cover and is easy to access, but does not have information on estimated snow depth. It is still a good resource if you are interested in snow cover, including historic data.

The Interactive Multisensor Snow and Ice Mapping System (IMS) (http://espcgis.nesdis.noaa.gov) provides analysis of snow and ice cover for the Northern Hemisphere at a 4 km resolution in an ESRI ArcIMS image map service. The main products page (http://www.natice.noaa.gov/ims/) provides access to the geospatially registered data in the web map service, as well as various gif images (see Figure 2) and time-animated image products that are maps but do not have world file georeferencing.

Figure 1. Interactive Map Webpage.

Figure 2. Ungeoreferenced GIF image example from 3 March 2009.

Data Listing (partial)

• Analyzed Snow and Ice from Satellites (SSDSnow)

 Access

Use of the ArcIMS interactive map interface is simple, and accessing the web map service is easy. 

Service Type: ESRI ArcIMS Image Service
Server Address: http://espcgis.nesdis.noaa.gov
Service Name: SSDSnowUsability

Figure 3. Snow/Ice data displayed overlaid in ArcGIS Explorer.

The data can also be directly consumed by clients that can read ESRI ArcIMS Image Map Services. The service has few layers and due to its light-weight is very responsize. it displayed very well in ArcGIS Explorer (build 500) over a cell data connection when the author was testing, see Figure 3). One minor issue if you are accessing the service via the interactive web map, is that the map is displayed in an unusual polar stereographic projection (see Figure 1), due to the fact that the system is focused on snow and ice cover for the Northern Hemisphere, it makes sense at least. 

Data Quality

The 4 km resolution is a bit limited, but for displaying snow/ice cover for regional views and even most States-level maps this service is certainly useful.  

Update Frequency 

Daily. 

Metadata

The  Analyzed Snow and Ice from Satellites (SSDSnow) layer has detailed metadata that even appears to be compliant with FGDC standards, unusual for a Federal data source.

Ratings

Accessibility Rating: Very Good

Usability Rating: Very Good

Data Quality Rating: Fair

Overall Rating: Good

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