Websites for some GPS receivers compatible with CMT iOS apps

Our iOS apps can work with any GPS receiver that is compatible with the Apple iPad and iPhone devices.

At the following three websites, you can find GIS-grade GPS receivers that claim 2 – 5 m accuracy:

https://gps.dualav.com/explore-by-product?category=GPS

https://bad-elf.com/pages/products

https://buy.garmin.com/en-US/US/p/645104

The Trimble R1 boasts 50 cm max. precision.

https://geospatial.trimble.com/products-and-solutions/trimble-r1

EOS and Geneq Inc. provide high-precision GNSS receivers.

Many of our customers are using the EOS Arrows series GNSS receivers with our iOS apps. In particular, iCMTGIS PRO can directly interface with the Arrow GNSS to obtain more accurate position data.
https://eos-gnss.com/product/

The SXBlue Platinum GNSS receivers from Geneq Inc. also work well with our iOS apps, and can directly interface with iCMTGIS PRO. Their SXPAD & SXPRO mobile data collectors can run our Windows Mobile 6.5 and WEHH Windows Embedded Handheld 6.5 compatible GPS/GIS data collection software programs.

https://sxbluegps.com/

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Does Farming GPS GIS III need wifi or cell service?

“Will this app allow me to plot a lines in my field and then allow me to follow them with a sprayer manually? Does It work without wifi or does it need cell service?”

Farming GPS GIS III provides the functionality for you to digitize Points, Lines and Areas over a displayed map. It also provides the Line Stakeout function to help you stay on the line while spraying.

Our apps do not need cell service.

The Apple Map that the Farming GPS GIS III uses needs wifi to load. You can load it at the office then use it in the field where there is no wifi as long as you do not close the map in the app.

Farming GPS GIS III will let you load a geotiff map (*.tif) to use in the background. Such off-line maps do not need wifi.

The accuracy of your work will depend on the GPS used. Many users get an external GPS receiver to use with their iPad devices. GIS grade GPS receivers claim 2-5 meter accuracy. High-precision GPS receivers are quite costly, but they can get down to sub-meter or cm-level accuracy.

Contour – Volume – Stakeout Questions

“My goal is to create an overview of my property and the complicated topographic conditions. Will I be able to create a map of my property with contour lines? Can I do that by importing a text file with hundreds of gps-position-altitude points? Is there another app might be more suitable for this purpose?”

If you have the boundary line of your property and a text file with 3-dimensional coordinates, the Contour – Volume – Stakeout app will be able to generate contour lines for the property. How good a representation you get will hinge on the resolution of the grid (number of points in relation to the length, width and height of the property) and the accuracy of the xyz coordinates.

If you have the Shapefiles for your property boundary, you can import it into the app to create the area representing the property. If your property boundary can be easily recognized on Apple Map, then you could use the app to digitize the property boundary.

Our iCMTGIS PRO app also includes the Contour-Volume function. It provides the function to use GPS to map property boundaries. The accuracy of the data depends on the accuracy of the GPS receiver. High-precision GPS receivers are quite expensive.

“So am I interpreting it properly .. I will not be able to register my property borders/shape with this app?”

The Contour – Volume – Stakeout app will let you get a GPS fix and compute a position when you use the Add Point manually function. You can then use the Add Area manually function to join those points to form an Area. However, the positions obtained this way are rather rough.

The GPS data collection function provided in the iCMTGIS PRO app will let you stand at a point and collect multiple GPS fixes to compute an averaged position. It will also let you walk along the boundary and record the boundary as a Line or Area Feature. Still, the accuracy hinges on the GPS receiver used, not the app. iCMTGIS PRO also provides the Deed Calls functionality to let you enter the property description in terms of distances and angles.

Can I trace an existing Line or Area while digitizing?

Many of our iOS apps provide the function for manually digitizing Point, Line and Area Features. While digitizing a Line or Area Feature, there is a way to incorporate part of an existing Line or Area into the new Feature. Simply tap on the “Include Line/Area Boundary” icon in the digitizing screen then tap on the existing Line/Area. Then, you will be prompted to tap on the starting and ending nodes of the segment to include. The existing Line/Area could be a previously digitized Feature or a line or polygon that you have imported from Shapefiles.

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.” (4/7/19 update: We used our Bad Elf GPS-2200 to record a couple GPS points today. The date recorded is correct.”

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.” (4/6/19 update: We used our Dual XGPS-150A to record a couple GPS points today. The date recorded is correct.”

For Garmin aviation devices, please read the following article:
https://s23634.pcdn.co/en-US/aviationalerts/wp-content/uploads/2019/01/1905A.pdf

For Trimble GNSS units, please read:
https://community.trimble.com/thread/5699-are-trimble-gnss-receivers-ready-for-the-gps-week-2019

Deed Calls – Grid – Stakeout app seems slow to indicate new direction

“I purchased deed calls-grid -stake out app for my iPad. I really like the app, except for the gps. Even with my bad elf gps connected it is very slow. . . . .I turn the bad elf on at least a half hour to an hour before I need ( batteries last all day), I start the app and make sure it is connected with gps when I get out of the truck. It just seems slow to adjust , even when I turn 180 degrees and head off in opposite direction. . . . I have an iPad 4 running 12.1.1.”

The app needs velocity to determine the direction. When you make a turn, try walking briskly in the new direction. If you stand still, the GPS marker will turn in all directions.

Following is the description for the GPS marker (indicator) in all of our apps:

“When GPS is turned on, there is a GPS marker to indicate your position. If you
walk at a brisk pace, the arrow inside the circle will point in the direction you are
walking.

The large arrow in the GPS marker indicating your current position will be a gray
color when your speed is very slow (e.g. less than 1 m/s). The arrow will change to
a red color when your speed is above 1 m/s. The direction of the arrow indicates
your current direction.”

Can you tell me how to delete my old jobs?

Please read the blog post at the following link:

https://icmtgis.wordpress.com/2015/07/19/how-do-you-delete-a-job-in-icmtgis-iii/

If your device is running iOS 11 or later, you could try using the iOS Files app to delete an old job file. Before deleting any job files, please make sure you have saved a copy of the job files to your PC or that you do not need the job files any more.