Overviews in LP360

LP360 has the ability to manage very large data sets. Unlike some other LIDAR processing applications, LAS files in LP360 are visible as LIDAR content regardless of the “zoom” level. In this article, I will explain how we accomplish this and what it means in terms of interacting with LP360.

When you are zoomed out on an image, you cannot see the same level of detail that you can see when you are viewing the image at one-to-one. This is because the screen on which you are viewing will not support the image resolution. For example, suppose you are viewing data in a window on your computer that is 100 by 100 pixels and that your image is 1,000 by 1,000 pixels. If you perfectly fit the image to your display window, each screen pixel covers 10 x 10 image pixels. To accommodate this difference, display software will amalgamate each 10 x 10 group of image pixels into a display pixel by a process such as averaging so that the image can be displayed. However, here’s the rub; to display the zoomed out image in the 100 x 100 window, all 1,000 x 1,000 image pixels have to be fetched from disk. This means (in our example) that 1 million pixels (1,000 × 1,000) have to be read to feed a display of only 10,000 pixels (100 × 100). This is a ratio of 100 to 1, a very inefficient (and slow) process.

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Lewis Graham has written 64 articles