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.

Do you have instructions on how I can navigate from point to point?

This is a question from a Stakeout iCMT user. The following answer applies to all of our apps that provide the Stakeout functionality.

Please tap the GPS icon and select “Turn GPS on”. GPS must be turned on for the Stakeout functions to be active (not grayed out).

You can use Point Stakeout to help you get to a specified point.

If you have a set of points and want to go from one point to the next in a given sequence, then first use the Add Line Manually function to form a Line Feature (a route). Select the Point Stakeout function then select the Line Feature that you have created as the Target. The app will help you go to the first node (a waypoint). Then you would tap the little arrowhead to advance to the next node per the node sequence in the Line Feature. That node becomes the new target to go to.

Under GPS – Stakeout Setup, you can set up the app so that it will sound an alarm whenever you are close to the specified node.

Is there a way to edit symbol size?

For our PC software programs and for our iOS apps that provide the Topic View, you can double-click on the symbol in Topic View to call up the symbols page. On this page you will see the option to change the symbol, size and color. The changes you make will apply to all the Features on the selected Topic layer.

In an app like iCMTGIS II, if you just want to edit the symbol for an individual Feature, then select that Feature in Map View and tap on the Feature Properties icon at the top.

In PC-GIS 9 or PC-GIS X, double-click on a Feature then click on the “Symbol” button to access the symbols page for editing the symbol of that Feature.

Very slow to load Features from Shapefiles

A customer reported that it took a long time to load Shapefiles containing county property lines.

The U.S. county property line Shapefiles typically contain more than ten thousand polygons, along with a multitude of Attributes. As we mentioned in our 10/2/19 blog post, it will take time for the app to process a large job with a huge number of Features and Attributes. The app might also crash if a computation or file saving operation is disrupted for some reason.

Typically, you will want to just load the polygons that you need for a particular job, and not all of them. If you have a PC software program that will let you load the county property lines then let you export just the ones that you need, then please use it to prepare the corresponding Shapefiles for importing into the app.

Some of the iCMTGIS PRO customers use our PC-GIS X to accomplish this. PC-GIS X can import and export Shapefiles. So, the users would load the Shapefiles from the county then select the polygons they need to export to a new set of Shapefiles for importing into iCMTGIS PRO. After collecting GPS data, they would copy the .pmp file to their PC and open it in PC-GIS X. Then they will see the Feature data displayed along with the property lines . They will be able to make some changes, if they wish, then use the Plot Preview function to make a nice map for printing to a PDF file or a printer.

If you don’t need to refer to the property lines in the field, then you could simply load the county property polygons into PC-GIS X and combine them with the field data to complete the map.

Displaying iCMTGIS PRO data in PC-GIS X

“I have a project where I collected points using iCMT GIS Pro and EOS arrow. I would like to export the data points to PC GIS X and make a map with a parcel layer in the background and have the features collected shown with the symbol associated to that data point. Can this be done and if so what is the best way to perform this task?”

Yes, you can import the Shapefiles for the land parcels into your GPS Job file after switching the datum, coordinate system and distance unit in your GPS Job file to that used by the Shapefiles. After importing the parcels, you could switch back to the original datum, coordinate system and distance unit.

Shapefiles export does not retain the symbol and color assignment in iCMTGIS PRO. When you import the Shapefiles into PC-GIS X, the Features will be represented by the default symbols. In fact, you don’t need to export the Feature data to Shapefiles if you will be using PC-GIS X to work further with the Features.

iCMTGIS PRO stores your Feature data in a .pmp job file, which retains the symbol assignment. Simply use iTunes to copy the .pmp file to your PC then use PC-GIS X to open the .pmp file.

PC-GIS X can work with .pmp files as well as .fmp files. The .fmp file will store the Features as well as non-spatial map elements, such as a geo-referenced background map (*.tif) or shapes you’ve drawn using the drawing and lettering tools provided in the Palette. After opening a .pmp file in PC-GIS X, you can save the data in the .fmp format.

If you want to send a Job file from your PC to iCMTGIS PRO, please save the .fmp file as a .pmp file then copy it to the iCMTGIS PRO documents folder. A .pmp file only stores Feature data (including symbol assignment) but not the non-spatial data.

Where would I get a built-in background map that has at minimum local tax property lines?

Many states in the USA provide tax lot polygon maps on their website in the form of Shapefiles.

After you have downloaded the .zip file for the Shapefiles for your county, move it to your PC and unzip it to a folder on your PC. Use iTunes to copy the Shapefiles to the Documents folder of your iCMTGIS PRO, iCMTGIS III, iCMTGIS II, iGPSGIS II or Utility Data Collection app.

Then, you should be able to import the Shapefiles into a Job in your app. The data in the Shapefiles will become Feature Topics and Features in the Job, and you will be able to use them as background reference for doing GPS data collection.

iCMTGIS PRO updated to Release 1.1.2

New in this update:

1. Added GPS Quality as a built-in Attribute. You can now add the GPS data quality as a Feature Topic Attribute, which can be exported.

2. Fixed the problem of not automatically recording the default Value (set up in the Feature List used by a Job) for the first Feature logged during GPS data collection. Also fixed the issue of not automatically recording the default Value if a built-in Attribute has been added for the active Feature Topic.

3. Fixed bugs related to adding H_2DRMS as a Feature Topic Attribute, which can be exported.

4. App will issue an alert if user attempts to take the next step while the app is actively saving the Job data during GPS data collection.

Many thanks to the users who have reported the bugs and provided helpful suggestions.