Symbol used for representing recorded GPS Features

A customer reported that he had collected a number of points using iCMTGIS Pro and Arrow 100. Although the Topic in his Feature List have specific symbols assigned to them, the recorded points were displayed using the default blue dot symbol.

We have determined that this is a software bug in some of our apps. We will work on fixing this issue. In the mean time, you can click the “Pattern” button to select the desired symbol before storing data.

Which coordinate system should I use to collect GPS data?

“Is this the standard configuration ( WGS 84 LLA ) in iCMTGIS pro? Will it transfer back and forth in different coordinates? Or should I collect data also in NC State Plane since shapefiles are NC SP?”

Internally our software stores location data in WGS 84(1674)/ITRF08.

The options under Setup – Coordinate system is for you to select the coordinate system for displaying the position data.

Many people use the WGS 84(1674)/ITRF08 system on the iCMTGIS PRO because they are familiar with it.

You can set the iCMTGIS PRO to NC State Plane to collect GPS data if you wish to see the coordinates displayed in that system.

The important thing to remember is that when you are combining data (such as by importing Shapefiles), you must make sure that they are in the same coordinate system. You cannot add apples to oranges and expect to get a sum that represents the total number of oranges. In many cases you don’t have the option to change the coordinate system of the Shapefiles at their source. Therefore, our iCMTGIS PRO and PC software provides the ability to switch to the coordinate system used by the Shaepfiles to be imported.

Some people also use geo-referenced images in .tif format. Here again, you will need to find out what coordinate system the .tif file refers to before trying to load it into our software.

For people who make use of data from a RTK network, the Datum must be set to match that used by the RTK base station.

How to record points for contouring an area using iCMTGIS PRO

“I went to GPS > Collect, but I might have collected a line after that, rather than a traverse. Would that still be usable to generate contours?”

1. You can disconnect a Line Feature into Point Features by selecting that Line then using Utilities > Disconnect. Each node of a Line Feature is just one GPS fix. It may not be that accurate.

2. GPS > Collect > Traverse > Store will let you select a reference (starting Point) then enter slope distance, slope angle and bearing to create a new Point. You could generate new points this way when GPS signals are weak.

3. To properly record points for contouring, you will want to use GPS > Collect and record each point for a session of at least 30 seconds to obtain an averaged position. Generally, a longer session time results in better accuracy.

4. One thing to keep in mind is that vertical distance accuracy of GPS receivers is generally 3 times worse than horizontal distance accuracy.

How to record GPS points using iCMTGIS PRO and Arrow 100

“We are focusing in how to collect data points to create a block then a series of blocks to create a ranch then transfer to software to make a ranch map. Can you help us understand it better?”

Here are the steps for recording GPS data using iCMTGIS PRO and the Arrow 100.

1. Pair your Arrow 100 with your iPad via Bluetooth.

2. Start iCMTGI SPRO and create a Job file by tapping the Main Menu icon then selecting Job – New Job. Enter the new Job name. If you are using a Feature List for collecting the Points, please select it for the Job.

3. In iCMTGIS PRO tap the Main Menu icon then select Setup. Select GPS then tap on the check box for Enable the external GPS. Select the Arrow Device then tap on the green check mark at the top to confirm.

4. Tap on the GPS icon then select Turn External GPS On. You should hear the navigation beeps.

5. Select GPS – Collect.

6. Tap on New then select (if Feature List is used) or enter the Feature Name. As you would like to collect Points then use them to create Areas, please select Point and Static. Enter the Time Session in seconds then tap the green check mark to confirm.

7. If you are using a Feature List, the Attributes will be displayed, and you can enter the Values. Stand still and tap the Store button to start recording GPS position. You should hear the featuring beeps.

8. Walk to the next point and tap Store again. When done collecting all the Points, tap on the Exit button.

9. To create the Area Blocks, first create an Area Feature called Block by using Topic Menu – New Topic. Select Area as the type of the Feature. Then, select the Tools Menu and use Add Area manually to join the points to form the Area Feature.

10. As you have the PC-GIS X software, you could simply transfer the .pmp Job file to PC-GIS X after collecting the Points. Then use PC-GIS X to form the Area Features.

 

iCMTGIS PRO for soil & water application

Navigating back to a GPS point

“I am trying to find the right app for my application. What I need to do is use my iPad and Eos Arrow 100 GNSS receiver to collect and precisely navigate back to points on the ground. Getting back to the point with the subfoot precision my equipment is capable of has proven difficult with other apps because so many are based on my location being indicated by a large blue dot on an aerial photo or map. I need more precise navigation.”

As you can see from the Point Stakeout screen, there is a tiny green dot within the GPS marker to indicate the exact point location. When you get close to the target, you could turn off the Map.

For precise RTK surveying, users usually get the iCMTGIS PRO, which can get the GPS messages directly from the Arrow receiver and not have the data truncated by iOS. iCMTGIS PRO also provides many additional functions that you will find useful for your soil and water applications.

App to help plant trees?

“I am wondering if any of your programs could be used in my tractor as a way to guide me in driving a straight line when planting Christmas trees? Even if it doesn’t help me row by row could it be used to help me lay out a planting? Help to drive the first line across a field?”

The GPS system you will need to guide a tractor along a line to plant Christmas trees requires a high-precision GPS receiver used in conjunction with an app that will let you record a few reference points, draw the line on the map and guide the tractor along the line.

The actual equipment and app you select will depend on the accuracy you wish to achieve. Of course, a high-accuracy system comes with a high cost.

The SXBlue Platinum and EOS Arrow Gold GPS receivers can be used with iCMTGIS III to achieve sub-meter accuracy.

The SXBlue Platinum and EOS Arrow Gold GPS receivers can be used with iCMTGIS PRO and a RTK network to achieve cm-level accuracy.

As there will also be visual cues to guide the tractor, do you think sub-meter accuracy will be sufficient for you?

Both iCMTGIS III and iCMTGIS PRO will let you load a geo-referenced background map (*.tif. *.pim or *.bmp). These are useful as a general reference, but they are not accurate enough to let you pin-point your first point or line by digitization.

You could use iCMTGIS III with a SXBlue Platinum or an EOS Arrow Gold GPS receiver to record the property boundary and the starting point to sub-meter accuracy. iCMTGIS III and iCMTGIS PRO will let you create a grid over the property to indicate where the trees are to be planted.

iCMTGIS III and iCMTGIS PRO provide the Stakeout functions to guide you along the grid lines. These apps will display how far the tractor deviates from the line. You could also set up the apps to keep beeping as long as the tractor stays on the line within the specified tolerance.

Recording property lines

“I have recently purchased a 19 acre field/forest and have a new survey PLAT with freshly marked property pins. I would like to permanently record the data points onto a GPS device such as an iPhone for when the markers are removed (to install fences, argue with neighbors over hunting areas, etc.). I need the app to be able to guide me between the pins while walking with the GPS.”

For your intended use, you will need a high-precision GPS receiver. The GPS built into the iPhone is good to about 30 ft or worse in some situations. This is in adequate for settling arguments between neighbors.

The Deed Calls and Deed Calls & Stakeout apps are for drawing the deed plot by entering the deed calls (bearing and distance information). The Deed Calls & Stakeout app will then be able to guide you along this deed plot. To correctly place the plot on the map on the iPhone, you will need to have the GPS coordinates for the first point. These two apps do provide a “Pick GPS” button for you to grab one GPS fix. However, it will be an approximate position if you are just using the iPhone built-in GPS.

As you want to record the positions of the stake points and also be guided to walk between the pins, the system to use is a high-precision GPS receiver like the iSXBlue II+ GNSS or the EOS Arrow Gold with an iPhone or iPad running iCMTGIS III or iCMTGIS PRO. The iCMTGIS III and iCMTGIS PRO apps will let you record a position by taking many GPS fixes and averaging them. They will also let you record an irregular property boundary by walking along the boundary. They provide the Point Stakeout (to guide you to the pins later) and Line Stakeout functions (for guiding you along the property boundary later). They also provide the Deed Calls functionality.

In summary, it boils down to the desired accuracy. Using an iPhone running Deed Calls or Deed Calls & Stakeout app might be adequate for a realtor or a forester (to do a quick approximate deed plot). Deed Calls & Stakeout is useful for someone who needs to find old stakes based on a deed plot. To record accurate stake positions, you will definitely need a much better GPS than the iPhone GPS. If you can accept a 2 m – 5 m (6 ft – 15 ft) error, then you could consider using the less expensive Dual XGPS-150A or Bad Elf GPS.

Apps for recording GPS points

“I have downloaded your Deed Calls application and it works great. However, I am looking for an additional feature and I’m unsure which product will get me what I would like. I need to enter deed calls AND use the GPS to set points all in the same area. With deed calls, it seems to allow me to set the starting point with GPS, but after that, seems that I have to have the deed calls.”

The PickGPS function just grabs one GPS fix. This, in combination with the GPS that comes with the iPhone and iPad devices, which lacks accuracy, will not give you an accurate starting point for your deed plot. You will want to check the deed plot against the satellite map to see it is located approximately correctly.

The Deed Calls Pro app provides both the ability to create a deed plot and the ability to digitize points using PickGPS.

Our Forester GPS GIS III and Farming GPS GIS III for use with iPad devices and the iCMTGIS III and iCMTGIS PRO apps for use with either iPhone or iPad devices, provide the Deed Calls function plus a GPS Point data collection function that will let you record multiple GPS fixes at one location and compute the average position.

The accuracy of your work will still depend on the precision of the GPS receiver you use. Some of our customers use the Dual XGPS-150 or the Bad Elf GPS 2200 to get 2-5 meter horizontal accuracy. Other customers use high-precision GPS receivers (iSXBlue II+ GNSS and EOS Arrow GNSS) to obtain better position accuracy.

How can I make sure I’m capturing points meeting a PDOP threshold?

If you are using iCMTGIS PRO and an iSXBlue II or EOS Arrow GPS receiver, you can set the PDOP limit for GPS data collection as follows:

1. Turn off GPS from all apps on your iOS device.

2. Select Main Menu – Setup and mark the check box for “Enable the external GPS“.

3. Select the appropriate device protocol for the GPS receiver.

4. Tap on the pull-down arrow for PDOP Mask and select the desired PDOP Mask level. If you only want to record position data for which the elevation can be computed, then also mark the “3D Only” check box. Tap on OK to save the setting and close the screen.

5. Tap on the GPS icon then select “Turn external GPS on”.

Using iCMTGIS PRO and EOS Arrow Gold to collect UAV ground control point data

“I have a UAV company and do lots of inspections and mapping with my drones, when I am doing the mapping in the past I have hired crews with total stations to get me my GCP’s so now I want to do this myself. I get the X, Y and Z data from them so I can input them into my Pix4D software. I know your software allows me to collect the X and Y data but can I also collect the Z data accurately?  . . . . .  Please see the attached GCP information sheet I get from survey companies. As long as I can get this data it will be great.”

These appear to be the coordinates for Point Features. So, you will want to first set up the coordinate system and distance unit to use. If you are using UTM, select the proper zone.

Now create a new Point Topic and give it a name, such as GCP (for ground control point). Then Edit the GCP Topic and add the built-in Attributes: Position_X, Position_Y and Elev_Z as well as the GCP ID attribute.

With the GCP Topic selected, turn on GPS and record a few points. After ending the point data collection, you can turn on Sheet View and look at the data in a spread-sheet arrangement.

You can export the point coordinates and attributes data to Shapefiles or a text file.

As the GCPs are control points, you will need to use the Arrow Gold GNSS receiver in RTK mode to get better accuracy.

Under Setup – GPS, select “Enable the External GPS” and select the protocol for the EOS GNSS receiver. This way, you will be able to see the RMS error of the GPS data output by the GNSS receiver displayed at the top of the Map View screen.

How to use iCMTGIS III to check GPS accuracy

“I have purchased the iCMTGIS III and I am using a TIFF image as a background map. I am having problems with the GPS not very close to a known point. Do you have any suggestions? I am using a Bad Elf Pro+ as an external GPS it says it is supposed to have 3-5 meter accuracy. Do you suggest another GPS? Is there only one place to change coordinate system or is there other parameters that may need to be changed to get acceptable accuracy?”

Does your iPad come with GPS? Perhaps the iPad is using its internal GPS, which has poor accuracy. Please turn off GPS from all the apps on your iPad. Then, with the Bad Elf Pro+ connected to your iPad and turned on, run iCMTGIS III and select GPS – Turn on GPS.

Another way to ensure that the iPad uses the external GPS is to turn on the Airplane mode under the iPad Settings. For details, please see our blog post at:
https://icmtgis.wordpress.com/2014/03/05/using-an-external-gps-with-icmtgis-ii-on-ipad/

To check the accuracy of the GPS receiver against the LLA coordinates of a known point or survey mark, you could first create a Point Topic then add a Point by using the Add Point by Coordinates function from the Tools menu. Enter the latitude and longitude of the known point. With the Bad Elf GPS having been turned on for a few minutes, check the location of the GPS marker against the known point. The published accuracy is an average value.

To record a Point Feature, please use GPS – Collect and log GPS point data for 5 minutes or longer. The app will compute and display the average point position. Measure the distance between the recorded point and the known point.

Can I use iCMTGIS PRO on my iPad to stakeout to survey points and also develop custom data collection forms?

1. Stakeout to survey points

The GPS – Point Stakeout function in iCMTGIS PRO can take you to the survey points. How close you can get to the survey points depends on the GPS receiver. The built-in GPS of an iPad device has an accuracy of about 10 meters (sometimes better, sometimes worse). If there are markers on your survey points, then you could identify the marked points after you get to its vicinity. Otherwise, you will need a high-precision GPS receiver, such as the EOS Arrow or iSXBlue II GNSS to take you closer to the point position. To pin-point a previously surveyed point, you will need to connect the EOS Arrow 200 or iSXBlue II GNSS to a RTK network in your area.

2. Custom data collection forms

The GPS – Collect function will let you record Attribute values during data collection. You can use the GPS – Feature List function to set up the Features/Attributes/Values for your project. Similar projects can share the same Feature List.

GPS Feature Data Collection

GPS Feature Data Collection

You can set up custom value lists to facilitate data collection. During GPS data collection you can have the app display the Attribute fields. You can enter data manually or select the desired data from the pre-defined list. The collected data can later be presented in Sheet View and edited.

If you are not after entering data while recording GPS positions, but are interested in designing your own report forms for entering data for a certain site, then please consider our Wetland & Stakeout app.

Quick way to measure acreages using GPS

GPS Data Collection for Area Feature

                                      GPS Data Collection for Area Feature

“I currently have iCMTgisII on my ipad. I am looking for the simplest and quickest way to measure acreages using track points. what is the quickest way to achieve this using that program?”

You can use the GPS/Collect function to record an Area Feature while walking or driving along the perimeter of an area you wish to measure. The standard procedure is to first define a Feature List suitable for your project to facilitate data collection. However, if you just want to quickly map an area, you can use the following steps.

1. Tap on the GPS icon then select “Turn GPS ON“. Wait 5 – 10 minutes for it to stabilize..

2. Select GPS – Collect.

3. Tap on the “Area” tab.

4. Enter the Feature Topic Name, such as “area”. The app automatically assigns “area001” as the first Feature ID.

5. Tap on the Store button in the data collection panel then start walking. By default, one GPS fix will be recorded per second.

6. When you have walked around the area and come back to the starting point, tap the Stop button.

7. If you want to record another area, go to the start point for that area and tap on Store. The app will have assigned area002 as the Feature ID for this second area.

8. When done with the data collection, tap on the Exit button.

9. Back in the Map View, tap the Zoom-Fit icon to see all the areas in the screen. Tap on one of the areas to highlight it. Tap on the Feature Properties icon then tap on the “Length/Area” tab to see the perimeter and area values.

One thing to note is that the GPS on your iPAD is not quite accurate. It is probably fine for measuring very large acreages. For better accuracy (2-5 meters), many of our app users use a compatible external GPS receiver, such as the Dual XGPS-150A or the Bad Elf GPS. GPS receivers that provide sub-meter accuracy, such as the iSXBlue II and the EOS Arrow, have a higher price tag.

If I purchase iCMTGIS PRO for my iPhone, can I also install it on my iPad?

Some of our apps were designed specifically for the iPhone or specifically for the iPad, but iCMTGIS III and iCMTGIS PRO were designed for use on both the iPhone and the iPad devices.

You can install your purchase of this app on your iPhone and iPad devices as long as your devices use the same Apple ID.

A related question:

“If I get a new iPhone in the future, will I be able to re-download and install iCMTGIS Pro on my new device without having to purchase it again?”

Once you have purchased the iCMTGIS PRO app, you can install it in any new iPad or iPhone device that you purchase as long as the devices use the same Apple ID.

Please note that our iOS apps are sold via the Apple App Store, and all purchases and installations are governed by Apple.

 

How to recover custom configuration after updating iCMTGIS III

“I’ve been puzzled by question that whereas iCMTGIS iii keeps its settings every time we updated it, a few settings have gone to the default (for us: Elevation and Angle, and Data Collection). Can we have:
1) The configuration not touched during update (unless configuration parameters changed);
2) Float number for the Local Time Offset in Data Collection?
Otherwise, the iCMTGIS-iii has been working fine.”

The settings for Elevation and Angle and Data Collection are saved in the file named “cmtgis3.cfg“.

After setting up the desired parameters, you can copy cmtgis.cfg to your PC for safekeeping.

After a software update, the app must go back to the default system configuration, but you can restore your custom configuration.

To do so, please first run the app and open a Job so you will be able to access the app’s Documents folder.

Then close the app by double-clicking the Home button and then flicking the app screen upward and out of sight.

Now copy your custom cmtgis3.cfg back to the app’s Documents folder to overwrite the default configuration file. You should see your custom settings for Elevation and Angle and Data Collection.