April 9, 2024

Exploring the Path Profile Tool in Global Mapper

Written by: David McKittrick


At the risk of alienating the members of the Flat Earth Society, allow me to state for the record that the planet on which you are currently standing, sitting, lying, or temporarily suspended above while awaiting clearance to land on, is definitively un-flat. On a planetary scale – and according to those who have undertaken much research on the subject – the Earth is an oblate spheroid, a slightly squished orb, so to speak. But alas, that’s a topic for another blog. More appropriate in the context of this blog is the degree to which this un-flatness is evident at a local level. The world is a texturally interesting place, full of hills and dales, knolls and depressions, peaks and troughs, which brings us, conveniently, to Global Mapper and the Path Profile tool.

Those of you who have been paying attention over recent years may have noticed that a significant chunk of the software’s development work has lately focused on creating, visualizing, and analyzing the three-dimensionality of the world, or a relevant portion thereof. While the 3D Viewer understandably garners most oohs and aahs and accolades when it comes to the display of 3D data, the Path Profile tool is most definitely worth a second look. Some might even suggest that it offers more useful functionality and utility than the remote oblique perspective of the 3D Viewer. Let’s take a closer look, and we’ll leave it up to you, the reader, to decide.

First a Definition: What Exactly is the Path Profile Tool?

Simply stated, the Path Profile tool is a cross-sectional viewer. Imagine using a knife to slice the terrain, then viewing it from the side. That, in a nutshell, is the Path Profile tool. As we will see, there are multiple flavors of this tool that provide a plethora of derivative functionality, but let’s begin with the basics.

A cross-sectional view of data shown in Global Mapper’s Path Profile tool
A cross-sectional view created in Global Mapper’s Path Profile tool

Accessed using the Path Profile button in the Analysis toolbar or, for those able to memorize such things, by using the Alt+L keyboard shortcut, the tool temporarily hijacks your cursor and functions much like the Digitizer’s line tool. Simply draw a line by left-clicking and finish the line by right-clicking, after which the profile will be automatically displayed. Alternatively, an existing line, either drawn or imported, can be selected and profiled using the Path Profile option in the Digitizer’s Analysis/Measurement sub-menu.

Scaling the Path Profile Viewer

No matter which method was used to create the Path Profile, the resulting terrain cutaway will likely seem to be somewhat exaggerated on the vertical scale, which is normal and expected. The profile view, by default, is rendered to fill the extent of the size of the window. Enlarge or reduce the size of the window, and the profile view will be scaled accordingly. Needless to say, the behavior can be modified. The ability to match vertical and horizontal scales, along with more options than we have time to introduce in this brief article, is available in the Path Profile Settings window.

A cross-sectional view in Global Mapper's path profile view with matching horizontal and vertical scales
A cross-sectional view with matching horizontal and vertical scales
One of the interesting byproducts of the profile functionality is a report generated from the underlying terrain characteristics. Accessed by right-clicking in the profile window, the Path Profile Details report includes such information as 3D surface distance, total climbing and descending distance, and maximum slope angle. All of which can be copied and pasted into an external document.
Dialog of a report describing the characteristics of the underlying terrain.
A report describing the characteristics of the underlying terrain

Line-of-Sight Analysis

While we’re still considering the standard profile view, it is worth mentioning the Line-of-Sight analysis functionality, which is built into the Path Profile window. This simple tool helps answer the question, ‘Can I see point A from point B?’ Or, more specifically, ‘If I am a certain height above the ground, are there any obstructions that would impact the view or interfere with a transmitted radio signal from point A for someone standing at B?’ Or variations on that theme. The answer to the aforementioned question is clearly displayed in the Path Profile window.

Line of Sight Analysis showing obstructions along the path
Line of Sight Analysis showing obstructions along the path

Perpendicular and Parallel Views

What if a single cutaway view doesn’t quite tell the complete story? Thankfully Global Mapper offers a couple of options for displaying a series of Path Profile views. The first uses the originally drawn line as the basis for a series of cross-sectional views that are generated perpendicular to that line. The second, and more recent addition to the Path Profile functionality, provides the option to create an array of profiles parallel to the original. In both cases, the spacing of the sequential profile views and other settings are defined in the Path Profile Settings window.

One part from a series of perpendicular profiles representing the cross-section of a river valley
One of a series of perpendicular profiles representing the cross-section of a river valley

Viewing Points Clouds in the Path Profile Tool

For users of Global Mapper Pro, the Path Profile functionality can also be applied to lidar or 3D point cloud data, which provides a very effective way to expose vertical anomalies in the data and, if necessary, to select and edit or delete the points in question. When applied to a point cloud, the procedure for rendering the profile is fundamentally different than that used with a raster terrain layer. Geometrically speaking, a line drawn through an array of points will not intersect any of those points because a point has no dimension. The solution is to create a buffer on either side of the profile line within which all of the points are displayed. Obviously, the extent of the buffer and the corresponding width of the swath will determine the density of the points displayed. Again, the settings pertaining to perpendicular and parallel profiling are available in the Path Profile settings window.

A swath of lidar data rendered in the Path Profile window
A swath of lidar data rendered in the Path Profile window

One final word: At the beginning of the article, we briefly referenced the 3D Viewer and suggested that, in certain situations, it takes a back seat to the functionally more versatile Path Profile tool, but alas, it’s not always a case of either/or. It is possible to display the Path Profile as a cutaway of the terrain in the 3D Viewer, essentially combining both views. In the Data Display section of the Path Profile Settings window, the 3D Display Mode dropdown list includes the option to Render a Single Terrain Cutaway. When selected, the 3D Viewer renders the cross-sectional view with the terrain extending to the horizon.

The Path Profile rendered in the 3D Viewer as a terrain cutaway
The Path Profile rendered in the 3D Viewer as a terrain cutaway

For those of us who still eschew flat-earth ideology, Global Mapper’s Path Profile tool offers a visually stunning and functionally invaluable tool for displaying and analyzing the three-dimensional world from a cross-sectional perspective.

To check out the Path Profile tool and other 3D data viewing tools, download a free 14-day trial today! If you have any questions, please contact us! For more information on using the Path Profile tool, check out this YouTube video — Ask The Experts: How do I use Terrain Painting in the Path Profile Tool?

Try the Path Profile tool in Global Mapper with a free 14-day trial! If you have any questions, please contact us.

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