Your GNSS Training Headquarters for GIS and Mapping Applications

VRS Links

A VRS is a Virtual Reference Station capable of supplying a real time, network adjusted solution to those using a high accuracy GNSS receiver, providing the user has access to the Internet.  By definition, a VRS is a collection of GNSS base stations that consist of a GNSS antenna, receiver, consistent power and Internet upload capabilities.  The phase center of each GNSS antenna is considered to be a known point.  The stations are sending measurement data to a central computer or server 24 hours a day, 7 days a week.  When the user connects to the server, types in their login and password information, they can receive corrections to their GNSS rover, providing a high accuracy solution.  This data stream is typically accessed via a cellular modem, either built into the receiver itself, or through a smartphone or Mi-Fi device.  Here are some links:

Oregon Realtime GPS Network (ORGN) - This network consists of mainly GPS-only stations at this time (June 2015) but there are plans to upgrade all stations to GNSS (GPS + GLONASS).  Click on this link to see which stations within this network are GNSS (some are in Washington for those working in the northern part of Oregon).  There is currently no fee to access this network.  However, you must contact this person in order to obtain access.  

Washington State Reference Network (WSRN) - This network consists of GNSS stations (GPS + GLONASS).  There are only two or three of these stations that are not GNSS.  This system is mature in that it is well managed provides consistently excellent positioning.  The fee to access this network is $1900 per year, per receiver.  You can obtain a 90-day free subscription prior to making any payment.  To access this network you must contact any one of these three people.  Click here for a printable network map. 

If you have questions on how to connect to a VRS, contact me for assistance. 

General Links

Online Instructional Courses - these short, paid courses have been designed to assist you in learning specific tasks; data collection, post processing field data, exporting to GIS, etc. ‚Äč

Trimble Online GPS Planning Tool - we discovered a GPS planning tool on Trimble's website.  Use this to predict GNSS (GPS & GLONASS) satellite visibility over your project site before you go into the field.

What is the Geoid separation at my project site? - this site will provide you with the Geoid separation at a given location based on latitude, longitude.  Once calculated, you can type that value into the GPS Preferences/GPS Height tab in ArcPad.  This will allow ArcPad to collect elevations (MSL) rather than GPS heights (HAE).

Convert Latitude-Longitude Coordinates - use this online utility to convert Latitude, Longitude coordinate from any format to any other format. 

Ingress Protection Specifications (IP ratings) - this link describes the IP specifications that are assigned to each Trimble GPS unit.  It defines the level of environmental exposure the unit can withstand and remain fully operational.

Calculate Magnetic Declination -this link allows you to find out what the magnetic declination is in your area.


Maps and GPS Information  -this site is excellent for those looking for information about maps and recreational GPS receivers. You'll also find a large list of otherwise hard-to-find links on these and other related subjects.

What UTM Zone am I in?- This link takes you to a UTM Zone map that will help you determine what UTM Zone you are in when using GPS or when trying to register a raster image.  

USGS Map of UTM Zones  -Use this link to see a UTM Zone map of the US and lots of other information about projections, coordinate systems, etc.

Special "Earth View" Department

 A View of Earth from a Satellite- Would you like to see a planetary view of the earth from a satellite?  Go to this link.

GPS-GIS Users Groups

Oregon GPS Users Group

GPS Magazines for the Surveying and Mapping Industries

GPS World Magazine- Check out GPS World Magazine Online.  This is the premiere publication for the GPS industry.

XYhT (new publication) - Excellent new publication for the geospatial industry. 

CORS, NGS, USGS Coverage Maps & USGS NANU Subscription Services

CORS Coverage Map- Go to this link for the Continuously Operating Reference Station map.  These stations log code and carrier phase GPS data at various sampling rates.  These data can be used to process rover files collected with GPS mapping or survey systems. (important information about CORS)

FBN (Federal Base Network) Survey Status Map- looking for a control point somewhere near you?  Check out the Federal Base Network.  Simply go to your state and find details on the survey monument, including directions on how to find it.

NGS Data Sheets- visit this site to obtain information on control points in the High Accuracy Reference Network (HARN).

Washington State Department of Transportation Survey Monuments- find monuments within the state of Washington. 


Earthpoint -Use this link to convert latitude, longitude to township, range and section.  A very useful tool for those who need to know where they are in the older PLSS.  You can also "Fly to Google Earth" after the conversion is complete.

Atomic Clock on the Internet- this is a new government site providing the exact time anywhere in the US.  Included is a world map showing current daytime and nighttime areas.

Official NGS Geoid Page- Take a look at the services and links available on this home page for the latest Geoid model.