4

I'm new to ArcGIS and in a college course. I am trying to perform a Line of Sight analysis on a DEM raster, but it's only showing the endpoints, not the intermediate line with the visibility information in red and green.

I'm running it from the 3D analyst toolbar.

What it looks like line_of_sight_1

What the textbook says it should look like line_of_sight_2

I have double checked everything that the textbook, Discovering GIS and ArcGIS, has specified, and my prof has no clue what the error is.

What do you think is the problem here?

I know it's not much to go on, but I can't find a similar issue anywhere.

  • What is your projection currently set as? – whyzar Apr 20 '18 at 15:25
3

Esri has a good reference page Creating a line of sight

A line of sight is a graphic line between two points on a surface that shows where along the line the view is obstructed. The color of the line indicates the locations where the surface is visible and where it is hidden. The status bar indicates whether the target is visible or hidden.

enter image description here

You want to be sure to follow these steps:

The following steps describe how to conduct a line of sight analysis on a surface using the Create Line Of Sight interactive tool.

  1. In ArcMap, click the Create Line Of Sight button Create Line of Sight on the 3D Analyst toolbar.

  2. Optionally, type an observer offset. The observer offset is the eye level of the observer used to determine what is visible from the observer's location. An observer with a height of 0 will have a more obstructed view than an observer with a height value indicated. The height units are the same as the z-units of the surface.

  3. Optionally, type a target offset. The target offset is the height of the target point above the surface. A target with a height of 0 will be less visible than a target with a given height greater than 1.

  4. Optionally, check the box to model curvature and refraction. For this option to be enabled, the surface must have a defined spatial reference in projected coordinates and defined z-units.

  5. First, click the surface at the observer location, then click the surface at the target location. A colored line will be drawn indicating what is and what is not visible along the identified path from the observer location.

  • I did exactly that. My question is why it's not working, not how to do it. – Gruskinator Apr 20 '18 at 15:20
  • Can you provide more information related to your dataset coordinates and projection? Are you sure you have Z values in your dataset as well? – whyzar Apr 20 '18 at 15:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.