GPS week rollover in 2019

It’s been 19.7 years since the last GPS week rollover took place in the year 1999. If you are still using an old GPS receiver for data collection, then after April 6, 2019 the GPS data will be recorded with a much earlier date. Newer GPS/GNSS use 13 bits instead of 10 bits to encode the GPS week value, and therefore will continue to work properly for a much longer time before the GPS week will be rolled back again.

According to EOS CTO Jean-yves Lauture, “GPS Week Number Rollovers have been accounted for and implemented in all Arrow firmware builds available from Eos since the creation of the Arrow Series™ product line.”

According to Donnay Fleury Nahimana, PhD, GNSS Development and Test Specialist, the SXblue devices of Geneq Inc. will continue to function properly after the 6th of April 2019 GPS rollover. The units are running GNSS firmware that accounts for the GPS rollovers on 13 bits since 1999.

According to John McLellan, C.H.ElF (Chief Helper Elf), Bad Elf, LLC, “I’ve been reassured by our engineers that rollover week is handled on all of our devices.”

According to the Dual Tech Support Team, “XGPS150 units that were manufactured before December 2011 will be affected by the rollover event. There will be a firmware version that will resolve this issue.”

For Garmin aviation devices, please read the following article:

For Trimble GNSS units, please read:


Questions about CMTGIS III

1. I am testing GIS PRO, but may only need GIS III. What features are missing in III vs PRO?

a) Which GPS/GNSS receiver are you using? If it is an EOS Arrow or a SXBlue Platinum, then using the iCMTGIS PRO in the “Activate External GPS” mode will offer better accuracy. iCMTGIS III gets the position data from the iOS CoreLocation, which truncates the data values and compromises them somewhat. iCMTGIS PRO can also work in this mode, but it provides the “Activate External GPS” option and can get the NMEA messages directly from the receiver.

b) iCMTGIS III does not provide the Contour/Volume functionality.

These are the two main differences between the two apps. The digitization, data collection and import/export are basically the same. Please read the Help document for iCMTGIS III. and make sure it will do what you intend to use it for.

2. If I purchase the app, can I download it to both my iPad and iPhone?

Yes, as long as you are signed in with your Apple ID on both devices.

3. Is it possible to change the color or symbol of all existing features in a topic (layer) at one time? For example, if I import a points shapefile, and want to change all of the points to red from blue at once.

Please turn on Topic View. Double-click the symbol/pattern for the Topic of interest then select the new symbol/pattern.

4. Is it possible to copy an existing topic to create a new one? My main goal would be to utilize the same attribute table for the new topic.

If you are using a Feature List, you can duplicate the Topic Structure of a Feature Topic in the Feature List.

If you want to duplicate the Topic Structure for a Topic that was set up via Topic – Edit Topic, then you could use the Duplicate Topic function in PC-GIS X, which is an optional compatible software program for use with Windows 7, 8, or 10. Some of our iOS app users purchase the PC-GIS X program so they can produce a nice map in PDF or as a printout, complete with background image, north arrow, scale bar and company logo.

PC-GIS X is listed at $385 per software license. Currently we are offering PC-GIS X to iCMTGIS III and iCMTGIS PRO users for $231 per software license. The .pmp (Job) and .fbr (Feature List) files are interchangeable between PC-GIS X, iCMTGIS III and iCMTGIS PRO. Therefore, you can set up your Feature List and the map Job in PC-GIS X and duplicate the topic structure as many times as you wish. Then you can transfer the .fbr and .pmp files to iCMTGIS III or iCMTGIS PRO.

If you would like to try the PC-GIS DEMO software, please let us know. The DEMO version does not provide all the functionality of the official version. You will see the inactive functions grayed out. The DEMO software will let you import Shapefiles and digitize additional Feataures, but it will not let you save a job or export data.

5. Is there any grouping functionality in the topic tree? For a job with many topics, this can be helpful.

There is no grouping functionality in the topic tree. Within a Topic, you can have the Features grouped by using Topic – Classify.

You can move a Topic to any desired location in Topic View. Simply press and hold a Topic name then drag it to a new location. In fact, you will want to have the Point Topics placed above the Line and Area Topics so they won’t be obscured by the Line and Area Topics.

Video tutorials for apps

“Now I just need some tutorials on basic use. Is the help document pretty detailed, or would it be easier to use videos (which I generally prefer if available)? “

We have a couple tutorials listed at the bottom on the right side of our blog page.

You could get started with these two videos:

The Help document is quite detailed. Please read the section on Feature List.

How to install a TestFlight version of an app

If your email address has been added to the testers list for an iOS app, you will get an invitation email from Apple.

Please open that email then tap on the link provided in that email to run the TestFlight app. Then you will see the icon for the app to be tested with an Install button by its side.

Tap on that Install button to install the app to be tested.

Session time for collecting Nested Points

“I noticed that when I nest a point in a line, it defaults to 20 hits, rather than the 150 hits I had predefined the feature list. Reselecting the feature type resets the time interval properly, but it is initially set to 20s. Does that make sense?”

The GPS data collection parameters such as session time and interval defined in the Feature List are associated with the relevant Feature Topic. You have the freedom to record a nested point for any existing Point Topic or a new Point Topic created on the spot. The app will use the default parameter before you specify the Topic layer for the nested point.

If you wish, you could change the default Time Session under Setup – Data Collection.

Can a .pmp job be created on a PC?

“Is it possible to view the data collected by the ipad in the computer? Can the job creation .pmp be done on a PC?”

Yes. We have a PC-GIS X software program for use on Windows 7, 8, 10 that is compatible with iCMTGIS PRO, iCMTGIS III, Forester GPS GIS II/III, Farming GPS/GIS II/III and Utility Data Collection apps. The .pmp (Job) files, the .fbr (Feature List) files and the Shapefiles are interchangeable among these software programs.

You could also export the data to Shapefiles and view it in some other PC software program that works with Shapefiles.