When creating a virtual survey, it can be advantageous to look at the terrain through a different "lens". Terrain Lenses are a set of visualization tools built into Virtual Surveyor that enhance the ability to interpret, modify, and survey the terrain through dynamically displaying different visual filters over the terrain. This article explains the Terrain Lenses in Virtual Surveyor and lists some common uses for each one.

Overview

Terrain Lenses
Video

Terrain Lenses

Terrain lenses are enabled & disabled through the Terrain Lenses section of the ANALYSIS tab .

Terrain Lenses can be used at any time, but they are especially helpful when looking for variations in the terrain that may not be evident from the DSM and Ortho combined. These can include uses such as the Slope Steepness Lens for finding breaklines, or the Contour Lens for flow lines.

	Hill Shade Lens The Hill Shade lens is an exception to the lenses as it is not found in the ANALYSIS tab; it is displayed once you disable your orthomosaic in the Project View. The Hill Shade lens creates shadows on the terrain that make it much easier to visually interpret the elevation data. These shadows allow you to see relief or changes in the terrain, not only from a 3D perspective, but also from a 2D top-down perspective. The Hill Shade is important with every data set used in Virtual Surveyor, but especially in cases where no orthomosaic is available or where the orthomosaic is not crisp with detail. It is particularly useful when using lidar data in Virtual Surveyor, as in many cases there is not an accompanying orthomosaic to the lidar data set. Typical use cases: Working without an orthomosaic Lidar (video) Mitigating bad imagery Bathymetry
	Contours Lens The Contours help denote elevation throughout the terrain in a more precise way by displaying isolines. When displaying contours, you can quickly recognize common elevations, quick changes in elevation, or areas of little to no elevation change. The Contours default setting is to dynamically generate contour intervals based on your zoom level, but the lens also contains a interval function that allows you to control the spacing of contours dynamically, with changes showing up immediately in the Viewport. Major and minor contours are also displayed, with every 5 intervals. You can choose the color of the contours in the Major and Minor settings next to the Contours button. Typical use cases: Water flow lines Watershed analysis
	Slope Direction Lens Slope Direction is a unique tool to Virtual Surveyor that dynamically displays the direction of downslope through an easy to understand arrow graphic, overlaid onto the terrain. The arrows point in the direction of downslope based off the currently displayed terrain and area. The Slope Direction arrows also dynamically adjust in size and frequency depending on the zoom level you are viewing the terrain. You can choose the color of the arrows in the settings next to the Slope Direction button. Slope Direction is a great tool to understand the hydrology of a location. Typical use cases: Assess water flows Watershed analysis Road crown identification
	Slope Steepness Lens (Palette) The Slope Steepness lens is an alternative way to view elevation changes that focuses attention on areas of rapid elevation change. Areas of steeper slopes are colored in more intense colors (red, orange, and yellow), while areas of lower or no slopes are colored in shades of blue and up to green. Slope Steepness has many uses from safety (landslide) to making tools easier to use (digitization breaklines, or of top or bottom of features). Typical use cases: Slope stability Hauling route analysis Breaklines Identify crests & bunds Slope Steepness lens has 2 palettes to choose from. This view is the default palette for Slope Steepness. Slope Steepness Color Palette Values:
	Slope Angle Value	Slope Color
	0°	Cyan
	17°	Blue
	31°	Green
	45°	Yellow
	90°	Red
	Note: When the value is between two colors, the color is interpolated.
	Slope Steepness (Palette & Threshold) The secondary view palette for Slope Steepness allows you to specifically view slopes over a defined percentage, or threshold. You can access this lens by clicking onto the Palette button next to the Slope Steepness button and selecting the second option. When set to threshold mode, the Slope Steepness lens visualizes any slopes over the input threshold percent as red. The Slope Steepness Threshold lens is an important tool in locating slopes exceeding certain values. Typical use cases: Slope safety analysis Slope stability Hauling route analysis Mine safety This is a Ridge & Peak feature.
	Transparent Lens The Transparent lens allows you to see through the terrain and thus display any features that are beneath the terrain or going through it. Oftentimes, features digitized as point lines or polygons in one data set during a specific point in time can be underneath another data set at a different point in time. This can be the case due to changes in the terrain itself or vegetation growth obscuring the feature. Many types of work also focus on subterranean features such as mining, subsurface utility locating or engineering. Typical use cases: Mining Stockpile analysis Temporal mapping Subsurface utility mapping Supplemental survey data
	Elevation Lens The Elevation lens is used to represent elevation throughout the data set as a color gradient. The Elevation lens helps differentiate elevations and can be very helpful on very large data sets. A specific elevation range can also be set by putting in either a Min and / or Max value. Typical use cases: Elevation differentiation Identity high and lows Identity terrain depressions
	Graticule Lens The Graticule lens creates quadrants to give you a visual of the distance between project items and objects on your dataset. You can manually set the interval between lines to get a general sense of distancing for all visible elements on the terrain. You can also set the graticule anchor and azimuth to control the direction of the grid lines.
	Lens Combinations Beyond individual lenses being displayed one at a time, you can also display any combination of lenses at the same time. Any combination of lenses can be enabled through turning individual lenses on and off. By doing so, you are empowered to use these visual analysis tools in a way that makes discovering or extracting the data you need much easier. Lens Combinations open up the use of drone data in Virtual Surveyor to most applications. Find what works best for you!