Using iSXBlue II with iCMTGIS PRO

A customer using iSXBlue II GNSS with iCMTGIS PRO on an iPad mini 2 sent us a few question:

1) He wondered how to tell if the iPAD running iCMTGIS PRO is operating with the external SX Blue II.

With the iPad paired over Bluetooth with the iSXBlue II GNSS, tap on the GPS icon and select “Turn GPS on”. A GPS marker should appear and the app should issue a navigation beep once every second. This indicates that the app is receiving the GPS position data from the iPad, to which the iSXBlue II is sending the GPS signals.

Now, tap the GPS icon and select “Turn GPS off”. Select Main Menu – Setup then select GPS. In the GPS Setup screen, select “Enable the external GPS” then select “GNSS RECEIVER”. Set the threshold values as desired then tap on OK.

When you tap the GPS icon and select “Turn external GPS on”, a GPS status line should appear at the top of the screen, showing the number of satellites used, the PDOP value, etc. This indicates that the app is obtaining the GPS data directly from the external GPS/GNSS and not just getting the GPS position from the Apple CoreLocation.

2) With respect to the iSXBlue RTN NTRIP app, he asked, “I have this app and presume both your app and this one need to be open and running at the same time?”

RTK work means you are making use of the correction data sent out by a RTK network provider. Therefore, both the iSXBlue RTN NTRIP app and iCMTGIS PRO need to be open and running at the same time.

Does iCMTGIS PRO work with iSXBlue II GNSS selected as the External GPS receiver?

isxblue-ii-gnss-512x384Yes. After establishing Bluetooth connection, select iSXBlue or GNSS Receiver as the device and com.geneq.sxbluegpssource as the protocol. Then iCMTGIS PRO can receive and parse the NMEA message stream from the GNSS receiver and display information about the GPS status.

For RTK GPS surveying, you can run the iSXBlue RTN NTRIP client app to connect to the RTK network. (link to

Please see the following press releases:

American Surveyor



“I’m hesitant to spend $300 for the pro app if the $95 or $200 apps will suffice but I’m having a difficult time finding a comparison of features among the apps.”

Built-in Attributes 512x384

The three apps in the iCMTGIS-series all provide real-time GPS/GIS data collection and mapping functions. They will let you add user-defined Attributes for the recorded Features either manually or via a Feature List (attribute table). They will let you import and export Shapefiles. The differences are in the additional functionality provided by the more expensive apps.

If you just need to use GPS to map Points, Lines and Areas and record their associated descriptions, iCMTGIS II will do. iCMTGIS II can display the built-in Apple Map as background. If you would like to use an off-line geo-referenced background image, you will need to first use the optional PC-GIS software to convert the GeoTiff, GeoJpeg, ECW or MRSID files to the .pim file format. The .pim map can work in the “moving map” navigation mode. (Many of our existing customers already have the PC mapping software.) iCMTGIS II only works on an iPad device. Its iPhone equivalent is the iGPSGIS II app.

iCMTGIS III and iCMTGIS PRO can run on iPad and iPhone devices. These two apps will let you load a GeoTiff image or a .pim image as background map. They also provide a built-in Attribute List from which you can choose as additional Attributes for the Features. One of the screen shots displayed here shows the current list of built-in Attributes that you may elect to include in the data records for the Features recorded using GPS. Other additional functions are also provided in these apps, which help you stake points/lines/areas, create Features by entering distances and bearings, as well as classify, sort or perform a search on the Features in a Topic layer, import and export Point Features via a text file, etc.

GPS surveying using iPhone

GPS surveying using iPhone

iCMTGIS PRO has all the functionality of iCMTGIS III plus the Contour/Volume and Create Buffer functions. What sets it apart from the other two apps is that it provides the ability to receive the NMEA message stream directly from a few specific external GPS receivers. When the “Enable the External GPS” option is selected, iCMTGIS PRO will get the GPS information directly from the external GPS receiver rather than the iOS CoreLocation. This enables it to display a GPS status bar in real time.

At this time, EOS Arrow GPS receivers and Geneq iSXBlue II + GNSS can work in the “Enable the External GPS” mode. To use the EOS Arrow 200 and iCMTGIS PRO for RTK work, you must use the free EOS Tools Pro app to connect to the RTK network.