Save Time in the Field by Hiring Your Phone

*This article has been updated from the print edition.

by Ray Carnes

Most of the boundary surveyors I know spend significant amounts of time in the field locating control and have benefited from the published National Geodetic Survey Control Station data (also called Survey Mark Datasheets), either by visiting the NGS website or by searching for stations via applications such as Google Earth on their computers. Thanks to Critigen, this information is now available via your phone.


In as little as three taps of your finger, Find-A-Control can locate you using the GPS built into your phone, display nearby control, show you a bing image of a selected control point, and link you to the NGS datasheet. It is a free application supported on both Android phones and Apple iPhones, downloadable soon from either the Android Market or the Apple App Store. For a sneak peek at the Android version, visit


Once you open the application on your phone, you will see an easy-to-use interface showing a map and a few buttons. The Locate Phone button will center the map on your location using the GPS built into your phone. (The blue dot in Figure 1 represents the current GPS location of the phone.)

If you don’t have a GPS or you want to check out control in an area you will be visiting later, you can tap the Search button, type in a county, and drag the map to the location you need.

If you look closely at the map, you will see it shows the locations of various types of NGS control.

The Legend button shows you which types of control are currently turned on as well as the map symbols that represent them. The Road and Aerial buttons switch the map in the background, similar to most web and mobile mapping applications.

The legend display also gives you the ability to turn on and off each type of control by tapping it in the list (Figure 2).

To learn more about a particular control point, tap it and you will see a window showing a bing image of the location and the coordinates of the point with the name, permanent identifier, and USGS quad it is in (Figure 3).

If you click the Identify button you will be shown the NGS datasheet for that point (Figure 4).
That’s it—the easiest way I’ve seen yet to locate control in the field. If you have a phone you can do it, too, and you know the price is right!

More Information

Visit for a full list of features and to find out more about Critigen Solutions in surveying and mapping. Remember, if you have anything you’d like to ask me about this article or anything else related to GIS technology for CAD users, I can be reached at

RAY CARNES stumbled across GIS in 1992 and has used it ever since for managing data, modeling and analyzing geographic features, and helping users understand how it helps them make better decisions. He has spent nearly 20 years (10 with Esri) providing GIS and IT technical support, training, implementation, and development services.

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