GIS Data: Achieving centimeter-level accuracy

Why accuracy matters in GIS

Municipalities and utility companies rely on GIS systems to build and maintain reliable maps of their many assets, such as fire hydrants, water and gas lines, sewer lids, and more. Technicians use these systems to accurately record the location of newer assets, update the location of existing assets, and find assets that need maintenance or repair.

Accurate GIS mapping can save time by allowing workers to find assets and get to work more quickly, without spending time searching based on vague coordinates. This can translate to greater overall efficiency, but it can also be helpful when locating assets that may be more challenging to access for some reason. This may include:

  • Underground lines. With accurate GIS data, workers only have to dig once.
  • Heavy snowfall. Again, accurate GIS data can minimize the hassle of digging.
  • Urban congestion. Work crews can plan ahead and park their vehicles as close to an asset as possible.

And while emergencies in this context are rare, accurate coordinates can also save precious time when time is of the essence.

What are the different types of accuracy in GIS?

There are several tiers of accuracy in GIS.

The baseline for GIS is sub-meter accuracy, which is achieved using SBAS data. The name suggests that sub-meter accuracy has a one-meter margin of error when it comes to positioning, but this is not quite true. Generally, SBAS data is accurate within roughly two meters, but there is no way to prove or guarantee this. However, for many applications, the sub-meter accuracy of SBAS is sufficient, with no need for greater precision. Learn more about sub-meter accuracy and other GIS terms > 

The next level of precision for GIS is centimeter-level accuracy, which requires real-time kinematic (RTK) corrections of GNSS data. There are two ways to achieve centimeter-level accuracy with a GNSS receiver:

Pair your receiver with a base station over an NTRIP service.

NTRIP stands for Networked Transport of RTCM via Internet Protocol. NTRIP services provide RTK corrections to GNSS data. In the United States, many states have free NTRIP networks. Paid NTRIP services are available as well. Find NTRIP services in your state > 

Pair your receiver with your own base station.

Placing a base station, such as the Emlid Reach RS2+, on the roof of a building allows you to perform your own RTK corrections and achieve centimeter-level accuracy without having to engage a state agency or private contractor. 

Understanding GIS mapping tools

Accuracy in GIS is a product of reliable tools working in concert to collect, deliver, and display useful data. Most municipalities and utility companies will need a GNSS receiver and GIS field software, and some may also choose to invest in a GNSS base station.

Learn more about GIS mapping tools >

The Emlid Reach RX offers centimeter-level accuracy for an unbeatable price. Unlike other GNSS receivers, the Reach RX’s sub-centimeter capabilities are not locked behind a paywall or subscription. With a base station or NTRIP connection, you can start capturing sub-centimeter data in seconds.

Compare the Reach RX to other GNSS receivers > 

The Reach RX is compatible with virtually every GIS field software and app on the market, including ESRI ArcGIS Field Maps and QField, and is compatible with both Android and Apple iOS devices.

Whether you’re purchasing your first GNSS receiver or updating an existing fleet, the Emlid Reach RX offers the advanced capabilities and user-friendly interface favored by new and experienced users alike.

Ready to invest in a GIS solution? Learn more about the Emlid Reach RX >