Join us for an informative webinar to learn how the Colorado Department of Transportation (CDOT) surveyors and Subsurface Utility Engineering (SUE) managers successfully paired Trimble GNSS receivers with the ProStar PointMan mobile app to collect survey-grade utility locations and export the data into their Bentley MicroStation projects for precise, industry grade asset locations in utility, construction and survey specific workflows.
CDOT, along with many other DOT agencies, employs a specific utility coding system to manage its various utility assets as well as for easy standardized stylization.
Tuesday 9 June, 2:00 PM MDT
Rob Martindale, PLS, Program Manager, CDOT Utilities and Railroads, CDOT
Ben Skogen CPM, PointMan Product Manager, ProStar Geocorp
Stephanie Michaud P.Eng, Strategic Marketing Manager, Geospatial Field Solutions, Trimble Inc
Register for the webinar here.
As you know, Trimble Positions Desktop add-in stores projects and sessions in a database that we keep "behind the scenes" as much as possible. When you first installed the software, you would have used the Desktop Configuration application to create a new database configuration. This is typically a Jet (.mdb) or SQLite (if you installed the drivers) database, but can generally be any ODBC database connection that you've defined. This database has a schema (set of tables) that does get updated periodically as we develop new functionality that requires it. In previous versions of the software when we made a schema change, we required you to use the Desktop Configuration application to first update the schema by clicking the Test configuration link.
As a result of this requirement, we had recommended a "best practice" to be running the Desktop Configuration application after every upgrade just to validate and update the schema if necessary.
Starting at Trimble Positions Desktop add-in 10.8.0.1, this is no longer strictly necessary. The add-in itself will now self-update the database schema if required by that new version. You will be notified of the schema upgrade requirement the first time you run ArcGIS Desktop with the new version of the add-in loaded. You do have the option to not proceed with the schema upgrade if you would prefer to make a backup copy of the database first. This may be useful in situations where you anticipate a need to rollback to a previous version.
As a reminder, your project data will not be affected during these schema upgrades.
The Template Library stores all the templates you have created within your Trimble Connect project, enabling you to quickly add existing templates to a new map workspace.
You can select multiple templates from the library to add to a new workspace at the same time. Hold down the Ctrl key on your keyboard and click on the templates from the list. Once you’ve selected them, click the Use button to link those templates to the workspace, or choose the Duplicate option if you want to make copies of the original templates.
The TDC150 is a fully integrated, high-performance, easy-to-use handheld GNSS field computer for GIS data collection and management. With flexible accuracy options, this fully rugged, versatile device is ready for all of your field data projects.
In the webinar Trimble Mapping & GIS expert, Dan Colbert, discusses:
Watch a recording of the webinar on demand here.
The Trimble License Manager is where you can assign licenses to your field users for applications like Catalyst, Penmap, SiteVision, and TerraFlex. Before assigning licenses to your field users, you need to add them to the License Manager.
Accessing the License Manager:
Adding Users to the License Manager:
To add users to the License Manager click on the Users tab on the left. If you only need to add one or two users, click the Create User button and enter the user's email address and name.
Bulk Importing Users to License Manager:
If you need to add a larger set of users then there are two methods for bulk importing users - from a CSV file or from a Trimble Connect project.
Import from CSV File:
To import users from a CSV file, click Import Users and select From a file. Add their First Name, Last Name, and Email Address separated by a comma on each line.
Import from a Trimble Connect Project:
If you are using an application that utilizes Trimble Connect projects like SiteVision or TerraFlex you can import users you have already added to your Trimble Connect project. Click Import Users and select From Trimble Connect. Then select the region and project you want to import users from.
How to start a 30 day TerraFlex Trial for Trimble Connect
Sign into Trimble Connect https://connect.trimble.com/.
TerraFlex uses Trimble Connect to set up and organize your data collection projects, and to share data with other people in your organization. Once you create a Project and add a Map Workspace, you’ll Publish templates for use with TerraFlex.
Download TerraFlex to your mobile device for data collection.
The TerraFlex trial begins once you sign in to TerraFlex.
A TerraFlex trial lasts for 30 days and allows a user to collect up to 200 forms during those 30 days. Once you finish the trial, you can purchase a subscription to continue working on the TerraFlex project you were using during the (30 day / 200 form) trial period.
Here you can find all the tips published by product experts from the Trimble Mapping & GIS group in one handy place. Keep checking back or bookmark this page so you can find it easily later.
How to Create a Trimble ID for TerraFlex
Go to https://connect.trimble.com/. Trimble Connect is the cloud platform for creating and managing your TerraFlex data collection projects.
Click on “Sign in” on the Trimble Connect landing page.
Click on “Create new Trimble ID” now fill out the Create your account form. Click on Create a new account. Once you click on Create new account, you will be sent an email. Click the link in the email to activate the Trimble Connect account.
Trimble Corrections Hub is an automated corrections service that is bundled with Trimble Catalyst. Thanks the efforts of the Trimble Positioning Services team, the availability of corrections through the Hub (or TCH) now covers the entire continental United States, further improving the availability of high precision positioning 'out of the box' when using the Trimble Catalyst service. As of the day of publishing this blog post (May 2020), TCH now supports accuracy down to 10cm (RMS) in even more places, with RTX Fast coverage available in more than 3.5 million square miles in North America.
This expanded coverage means that even more Catalyst users can benefit from the TCH 'zero-config corrections' workflow. The latest coverage maps are available on the Catalyst webpage.
RTX Fast coverage has expanded to cover most of North America.
Catalyst subscribers are provided access to RTX through the Catalyst service and depending
on the level of subscription, delivers precision down to 10cm in real time.
This blog post discusses the basic concept of elevation, and the various ways that it can be expressed - particularly as it relates to GNSS receivers. We will cover terminology including ellipsoids, HAE, mean sea level, MSL height, geoids, geoid height, and orthometric height. After reading this article you should understand what these terms mean, and how to best interpret the data from your Trimble GNSS receiver so that you can be confident in the data you base your decision making on.
A common support request received by our Global Services team is to provide an explanation as to why the elevation output from a GNSS receiver doesn’t match what the user expects to see - sometimes with differences of tens of meters in elevation between an observed GNSS elevation and the elevation of a reference coordinate compared to the published coordinates recorded for historic reference monuments such as those available through the National Geodetic Survey for users in the USA.
The answer is normally that a user is comparing apples with oranges. Both elevation coordinates are usually correct - but are measured against different points and frames of reference. To understand what we mean, we need to understand how GNSS receivers normally work, and what frame of reference they are using. .
Elevation is the vertical difference between two points. GNSS elevation refers to the height you are measuring with your GNSS receiver, relative to a known reference surface.
However because the earth’s surface is highly irregular (e.g. due to geology), and ever changing (e.g. due to tectonic motion) making accurate calculations from this surface at a global scale is very difficult. So to simplify the calculation of elevations, geodesists use geometrical approximations of the earth’s surface to base the calculations on.
The approximated geometric shape used to represent the earth’s surface is a type of “vertical datum” called an ellipsoid (which is another word for a three-dimensional ellipse). Elevation at the surface of the ellipsoid is zero. Elevations measured above the ellipsoid surface are reported as positive elevations, and elevations measured below the ellipsoid surface are reported as negative elevations.
Ellipsoid surfaces can be defined very accurately using mathematical formulae, and so provide a very convenient way for mapping and surveying devices (like Trimble GNSS receivers) to create highly accurate digital measurements of the physical world.
Question: I thought the earth was a globe. Why do we use an ellipsoid, and not a sphere to represent the earth?
Answer: The earth is not perfectly round - and is in fact slightly wider (by about 42.7km) than it is tall. Ellipsoids allow a more accurate approximation of the earth’s surface.
Using a highly accurate mathematical model of the earth’s ellipsoid (the most common of which is referred to as the WGS84 ellipsoid), elevations relative to the ellipsoid based on a current GNSS position can be very accurately measured. Elevations using this method of measurement are referred to as heights above ellipsoid (HAE), or ellipsoidal height. HAE values can be either positive (for elevations above the ellipsoid surface) or negative (for elevations below the ellipsoid surface). HAE is the default value output by most GNSS receivers, and depending on the type and accuracy of your receiver, HAE can be computed to very precise values.
But there is a problem with HAE values - they are not very practical in real-world terms. Most practical use of GNSS is done relative to real-world features. And in the real-world the earth’s surface is not a perfect ellipsoid. The earth’s surface has mountains, valleys, and oceans and lakes (which also have mountains and valleys and other surface deformations). For most practical purposes the most intuitive elevation reference surface is “sea level.”
For example, it is not uncommon for a GNSS receiver to report an elevation (while standing on the beach) of +10 metres HAE. For the measured elevation to make sense it needs to be transformed to a different reference datum.
The most common vertical reference used in everyday language to represent altitude or elevation is the idea of mean sea level or MSL. For example, Denver, CO, is often referred to as the Mile High City. By an amazing stroke of good luck, the 13th step on the west side of the State Capitol Building is exactly 5,280 feet above mean sea level – one mile high.
Fun fact: Because the earth is dynamic (due to tectonics), and due to improving technology for measuring elevations, measured elevations change over time, based on redefinition of where sea level is and better surveying technology. Because of this, there are actually three separate 5,280 feet markers on the Capitol steps. The original, one from 1969, and another one from 2003.
Your GNSS receiver usually outputs a global MSL in the standard NMEA receiver output. Global MSL on a traditional GNSS receiver is generally based on a relatively coarse (and therefore imprecise) 10-minute by 10-minute grid, which is used to determine the offset between the reference ellipsoid and MSL at any given location on the earth. This relatively low resolution calculation can make the reported MSL elevations output by GNSS receivers off by several meters or more. This is fine for some applications, but for others (e.g. high accuracy mapping of underground assets) that’s a problem as local deformations and changes are not sufficiently accounted for.
A geoid is a highly accurate model of the local gravitational forces in a specific region of the world. Gravity force is affected by the density and structure of the earth’s surface. This means that in denser, and higher areas of the world the measured gravitational force is different to that of low-lying, less dense areas. This change in local gravity has an effect on the observed sea level at any given location.
Geoids measure the effects of variances in the local gravity on MSL using a sophisticated geometric representation of the actual physical shape of the earth. Each location or region in the world has its own local geoid(s), and these get updated from time to time; as measuring techniques change, or as the land deforms, local geoids are updated and re-released.
The current vertical datum in the United States is called NAVD88 (North American Vertical Datum of 1988) which incorporates the latest geoid model (see below; GEOID18). This will be changing in the next couple years.
Elevations, computed against localised vertical datums are computed using a highly accurate reference height (usually the ellipsoidal height calculated by your GNSS receiver), and this is referenced against the geoid model for the local area.
The geoid can be thought of as the detailed 3D surface of the earth. The shape of the geoid is the shape that the ocean surface would take under the influence of the gravity and rotation of the earth alone, assuming all other influences (such as winds and tides) were absent. The geoid surface is extended through the continents. Because of the massive size of our planet, it is difficult to visually distinguish the variance in surface gravity, and so digital renderings of the geoid tend to exaggerate the differences (by a factor of up to x10,000 or more) so that they can be visually seen. Below is an example of the visual representation of the Geoid showing the undulations and variations in the surface of the earth’s gravitational field. Here, geoid undulation is rendered in false color, with shaded relief and a vertical exaggeration scale factor of x10,000.
Image credit: By International Centre for Global Earth Models (ICGEM) - http://icgem.gfz-potsdam.de/vis3d/longtime / Ince, E. S., Barthelmes, F., Reißland, S., Elger, K., Förste, C., Flechtner, F., Schuh, H. (2019): ICGEM – 15 years of successful collection and distribution of global gravitational models, associated services and future plans. - Earth System Science Data, 11, pp. 647-674,DOI: http://doi.org/10.5194/essd-11-647-2019., CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=81462823
A geoid model is a grid of numeric values representing the geoid in a given region. It is similar to the MSL grid found in a GNSS receiver, but is defined with much higher resolution, is far more accurate, but is only applicable to a specific geographic region. Geoid models allow accurate conversion between ellipsoid height (HAE) and a mean sea level height based on a specific, local vertical datum. The geoid model can be interpolated to calculate an offset value called the “geoid height” or “geoid undulation" at the specific location being measured/calculated. This is the number we must use to convert between a global height referenced to a reference ellipsoid and a local height. This elevation is called orthometric height and is a much more usable and relevant height reference for most applications.
Fun fact: The etymological root of the word “orthometric” is the Greek prefix “ortho”, meaning “straight”, “upright”, “right” or “correct”.
Orthometric height is a relatively simple calculation:
H = h - N
H = Orthometric Height, the elevation value that is defined in terms of the local target vertical datum
h = Ellipsoidal Height, the elevation above or below the reference ellipsoid of the GNSS receiver
N = Geoid Height / Undulation, the difference between the geoid and ellipsoid in the current location
Orthometric height is the type of elevation data that surveyors, engineers, and other field workers need to work practically and accurately.
Depending on your field application or workflow, your software may calculate orthometric heights for you. Trimble Mobile Manager allows you to specify the latest geoid for your region, and the geoid file will be automatically downloaded to the app. Using the undulation information in the geoid file, the orthometric height is calculated directly in the app, and output alongside the ellipsoidal height.
For more information on using geoids and calculating orthometric heights in Trimble Mobile Manager, check out our 4 part series of blog posts: Orthometric Heights with Trimble GNSS & Esri Collector.
Banner image credit: https://medium.com/swlh/the-earths-weird-gravity-86449f8cb3e7
With configuration complete, you are ready for data collection in Esri Collector with orthmetric heights, directly with the field with your Trimble or Spectra Precision GNSS receiver.
Note: If you need to make changes to the GNSS configuration in TMM during data collection, best practice is to close Esri Collector completely, make the changes in TMM, verify expected results in TMM, and restart data collection in Esri Collector.
In the previous post in this series, we outlined the office configuration side for ArcGIS Pro or ArcMap for users of Esri Collector and the latest release of Trimble Mobile Manager (TMM). In this post, we describe the field side configuration of the workflow.
You can proceed with field device configuration by installing Trimble Mobile Manager version 184.108.40.2069 (or higher) and Esri Collector for ArcGIS version 2020.1.0 build 2913 (or higher) from the Google Play store or other means.
Open Esri Collector and sign-in using your credentials. Once signed in, you will see a list of web maps you have access to. It’s important first to configure the two Location settings in Esri Collector. These are both available in the Profile screen, accessible by clicking on the person icon in the upper right corner of the screen. The steps below are only a summary; for a complete description of Esri Collector functionality, refer to the Esri Collector documentation.