Description: Aggregated slopes for San Diego County. This dataset was built from a 10 meter GRID that was derived from a 2002 IfSAR elevation surface of the entire County. The IfSAR data was processed as first returns using X band data and that means that houses, trees, and other surface features show-up in the elevation model. Once the elevation model was reclassed and resized from its original resolution to a larger 10 meter resolution, the slope function was applied to it through GRID. This continuous surface built in GRID is the Raster GRID model called [sde.SANGIS.slope_stp_83]. This dataset was later reclassed and then vectorized into all slopes greater than 25%. That dataset exists as a vector dataset in SDE called [sde.SANGIS.SLOPE_STEEP25]. The GRID classifications in the source slope range from 0% slope to 2484.47753% slope. This translates essentially into flat to 87.70 degrees in angle. The reason 90 degree slopes are not recorded is most likely related to the 10 meter grid cell in horizontal distance. This translates into nowhere in the county is there a vertical elevation change greater than 787 feet (H= h+D*tan(Theta)) in a horizontal distance of less than 30 feet. This product recieved additional processing yielding four classifications of slopes: slopes less than 15% slope, slopes 15% to less than 25%, slopes 25% to less than 50% and slopes 50% or greater.
Service Item Id: 08b48187819049409761009dacd89cb1
Copyright Text: Ross Martin with County of San Diego, Planning and Development Services, LUEG GIS Service.