Positioning the Sun

Positioning the Sun in Map 360

The position of the sun and the timing of sunrise's and sunset's can be important factors to take into consideration in accident reconstruction. For example if the sun is directly shining in a driver's eyes at the time of the incident, then the position of the sun may be a factor. The suns position is calculated from an altitude(or elevation) and azimuth relative to the observers location. Altitude is the angular position of the sun above or below the horizon and the azimuth is the angular position of the sun relative to true north.

Here is a diagram illusrating how the Azimuth and Elevation angles are defined:

In Map360 users are able to replicate the angular position of the sun to provide accurate assesments for reconstruction of an incident scene.

First, you will need to know the following information to compute the correct azimuth and elevation angles of the sun at the location of the scene during the time of the incident.

1) The location of the incident

2) Time and date of the incident

Once you have gathered the required information, you may use this Link to help compute the azimuth and elevation angles of the sun.

When you have defined the Location, Date and Time of where the incident took place; you can see that it will calculate the Azimuth and Elevation in degrees at the specified local time in Degrees (°)

Users may now use the Azimuth and Elevation angle values provided in Map360 to illustrate the position the sun.

Click the links below to review a 4 part video on positioning the sun in Map360.

Part 1, Part 2, Part 3, Part 4

Follow the instructions below for a step by step guide:

1) Open .DWG "car flip at intersection.dwg"

This drawing is installed with Map 360 by default and can be found in: C:\Users\YourUserAccount\Documents\Leica Geosystems\IMS Map360\Forensic Scenes

2) Configure Scene Defaults for Units as Shown Below

3) Configure Drawing Settings same as below:

Clockwise Setting- We need to change the Angle Direction to clockwise because the Azimuth and Elevation angles supplied are referenced in a clockwise direction.

Angle Base- It is important to make the angle base change to 270 from the default 0 because the angle values supplied are referenced from North.

4) Store Point on the driver side of vehicle

Select Store and Edit Points > Pick Point > Store a point on the driver side of the vehicle with an elevation of 1.00 meters to represent the drivers level of sight.

5) Compute the Zenith Angle

Using the Azimuth and Elevation angles obtained from an external source, we can now draw a line from the Drivers position at eye level to the position of the Sun.

It is important to note that with the given elevation angle, we must subtract 90°. Map 360 expects a zenith angle so it is necessary to manually compute the elevation angle for Map 360 to correctly define the line.

Using the Diagram below we can see that to compute θZ we need to subtract 90° from the θel

θZ= 90° - θel

Ex) Azimuth Angle (θA) = 267.32°

Elevation Angle (θel) = 11°

θZ= 90° - 11° = 79°

Once you have computed the θZ we are now ready to Draw the position of the sun

6) Draw a Line to Represent the Suns Position

Ensure your node snap settings is ON

To start the Line command; Go to: Draw Tab > Line

Snap to the node of the point you stored on the drivers side of the vehicle to start the line.

Input the line information as shown below:

Input Format: @Distance (Always leave at 100)<Azimuth Angle <Zenith Angle

Ex) Azimuth Angle (θA) = 267.32°

Zenith Angle (θZ)= 79°

7) Use The Trajectory Cone Command to Insert the Sun

This command can be found in the Analysis Ribbon > Trajectory Cone

Once you prompt the command to start, select the Line that represents the Sun's Position and configure the trajectory cone settings as show below:

when your settings match the above picture, click on DRAW.

Your scene should now look like this:

8) Scale the Sun

After inserting the Sun, we will now use the Scale command to scale up with the Sun to illustrate the infinite distance.

You can find the Scale command in: Draw Ribbon > Scale

Once the command has been prompted:

a) Select the yellow trajectory cone and the line we that we drew for the suns position.

b) Snap to the point stored on the driver' side as the Base Point

c) Scale factor up by 100

9) Using the Explode Command to Clean Up the Sun

Now that we have scaled the sun up to illustrate that the distance of the sun is an infinte amount away, we use the explode command to help us clean up our scene.

Explode can be found in Draw Ribbon > Trim > Drop Down Selection for More Options > Explode

When you start the command, Select the yellow cone to explode. Once you have exploded the cone, delete the cylindrical portion of the cone so that we are left with just a circle (sun) and the line of sight to the sun

Your scene should now look like this:

10) Render The Scene

Your scene should now be cleaned up and ready to be viewed in render view.

The Render command can be found in: Home Ribbon > Render

Once you start the Render command a new viewing window appears:

a) Use the Target Pin to select the general area you would like to focus on, then use the middle mouse wheel to zoom into the area.

b) Then use Orbit Sphere to rotate around to get the view in the position you want

c) Go to: File> Save a picture of the view

The finished result should look similar to the picture below: