This guide describes how to access, begin using, and convert file types for elevation data covering the state of Oregon. The data described in this guide are processed from lidar (an acronym for Light Detection and Ranging) and are freely available in pre-packaged raster file formats from the Oregon Department of Geology and Mineral Industries (DOGAMI). While this guide covers how to use and convert the raster file formats available from DOGAMI into shapefiles and Computer-Aided Design (CAD) file formats, it is not meant to cover use or conversion from other file formats lidar data might be provided in besides raster file format (for example, LAS file format).
The remainder of this page describes what lidar and raster data are. The Accessing Oregon Lidar page of this guide provides information how to access, download, and unzip Oregon Lidar from DOGAMI, as well as the types of data contained in the downloaded files. The Converting Oregon Lidar page of this guide describes how to view DOGAMI Lidar in ESRI's ArcGIS software package, as well as how to convert lidar files to contour lines and to Computer-Aided Design file format. The Other Sources for Oregon Elevation Data page provides links to other websites besides DOGAMI where you can obtain free elevation data.
LIDAR is an acronym for Light Detection and Ranging, though often lidar may also be written in lower case letters. Lidar uses pulses of light in the form of lasers to measure distances. Lidar is commonly collected by aircraft. When lidar is combined with other data about aircraft location and movement it can be used to produce detailed topography.
Want to learn more about lidar? Check out the links below:
The Oregon lidar datasets are stored as raster files. Raster files consist of a matrix of cells (or pixels), which are sorted by rows and columns into a grid. Each cell has an assigned value representing information. In this case, raster cell values represent the elevation determined by lidar returns. Rasters are also frequently used to display information that varies over a continuous surface, such as temperature or imagery of earth acquired from aerial photography or satellites.