What are 4D products (DLG, DEM, DOM, DRG)?
4D products refer to DRG (digital raster map), DLG (digital wireframe), DEM (digital elevation model), DOM (Digital ortho image). 4D Composite product is a combination of any two or several product models in 4D products, generated by the fusion method of the superimposed products.
1. DRG (Digital raster map)
Digital raster maps are digital products in grid form of paper topographic maps. It can be used as a background to relate to other spatial information, for data collection, evaluation and update, and to derive new visual information from DOM and DEM integration.
2. DLG (digital line map)
vector datasets for tiered storage of basic geographic features on existing topographic maps. The digital line drawing includes both spatial information and attribute information, which can be used in all aspects of construction planning, resource management, investment environment analysis, as well as the spatial positioning basis of various professional information systems, such as population, resources, environment, traffic, security and so on.
3. DEM (digital elevation model)
A digital elevation model is a set of numbers that represent the undulating patterns of the ground in elevation. Can make the perspective, the sectional view, carries on the engineering earthwork calculation, the surface coverage area statistic, uses for with the elevation related landform morphological analysis, the pass-Sight condition analysis, the flood inundation area analysis.
4. DOM (Digital ortho image)
Using aerial photographs and remote sensing images, the image data generated by the image is trimmed according to the range of images. Its information is rich and intuitive, with good interpretation and measurable, which can directly extract the natural geography and socio-economic information.
Introduction and differentiation of 4D products (DLG, DEM, DOM, DRG)