![]() ![]() As a result, L1A data can match the DEM data exactly, making registration of the DEM to the overlay easier. Recall that the ASTER DEMs are actually produced from the L1A product (bands 3N and 3B). Data is recorded in 15 spectral bands, providing a wealth of data for many purposes, including image production. (The resolution of the L1A/L1B VNIR bands are 15m, double that of the DEM product at 30m.) This is the ideal situation for the production of DEM overlays. It's resolution actually exceeds that of the ASTER DEM product. With a little manipulation this data can be immensely useful to the terrain modeler nevertheless, because it is possible to process the data to achieve something like natural terrain coloration.ĪSTER L1A/L1B data, like its ASTER DEM counterpart is free. Only some of the ASTER sensors record in the visible spectrum, and the selection of wavelengths has nothing in particular to do with the production of natural appearing images. The sensors that acquire this type of data are primarily designed to collect reflected passive radiation outside the visible spectrum to assist scientists in studies of deforestation, crop analysis, land use analysis and global climate change. This article will look at a few possibilities using the ASTER L1A and L1B data sets.ĪSTER L1A/L1B data was not designed to produce overlay material for DTMs at all. Fortunately, such data is available from the same source. While the availability of free International DEM data is truly exciting to the terrain modeler, what we need to complement the DEMs and to make useful digital terrain models (DTMs) is equally high quality overlay imagery. In previous articles we outlined procedures and techniques for acquiring and using ASTER DEM data from the EOS Data Gateway. Modeling and Mapping using DEM, SDTS, DRG, DLG and DTED L1A/L1B False Color Composites Digital Terrain Modeling and Mapping Digital Elevation Model Digital Terrain Modeling ![]()
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