blognahmarlin: Create 3D Images Using Global Mapper

Guadalupe Island - Landsat Image N-11_25_2000 (1:200,000)

During the later part of December 2006, I worked on the Guadalupe Island project. I began with a Landsat image. After a quick, yet thorough, inspection, I determined that the Landsat image was not satisfactory for an EVS quality project. First, and foremost, far too many clouds obscured the island.

Guadalupe Island - TerraMetrics Image (1-200,000)

Guadalupe Island - Digital Globe Image From Google Earth (1:200,000)

So, I visited Google Earth and found a great 1-meter resolution Digital Globe image. I used it to digitize my various layers of information. Around the same time, I began using SRTM data to construct contours for many of my completed projects. I used the following SRTM data to construct contours for Guadalupe Island.

Guadalupe Island - SRTM Image N29W119 and N28W119 (1:200,000)

From these images, using Global Mapper, contours were quickly and easily generated. I knew Global Mapper had a 3D feature and if you have loaded the proper data, SRTM for example, 3D images can be easily rendered. I had never used it.

Guadalupe Island - TerraMetrics Image In Global Mapper (1-200,000)

Guadalupe Island - TerraMetrics Image Loaded Into Global Mapper (1:200,000)

First you need the image you will drape over the SRTM data. This image must be loaded on top of the SRTM data. So I loaded the Digital Globe images of Guadalupe Island into Global Mapper. All four of the images were at a scale of 1:62,000.

Global Mapper - Select 3D Option

To select the 3D option, you merely point and click.

Global Mapper - A 3D View of Guadalupe Island

And there you have it - a 3D view of Guadalupe Island. Needless to say, you can control the vertical exaggeration, ocean depth and other aspects of the image. The image can be tilted, twisted, zoomed and other manuvers. You can snap a picture at each juncture.

Guadalupe Island - 3D Effect From SW to NE

Guadalupe Island 3D View From SW to NE

This view shows a deficiency of the SRTM data. If something obscured the elevation data gathered by the Shuttle, you are left with what is called a void. There is data available that attempts to fill the voids with reliable alternative elevation data. A couple of areas along the western side of Guadalupe are actually voids. The elevation data at those voids are greatly exagerated. As I gather more SRTM data, I will replace the SRTM voids with SRTM with filled voids.