The standard format for elevation data in gis is a digital elevation model dem in raster format. I have been with esri in software products since 1994. In this case changing the z factor to 2 will multiply the input dem by 2. This zfactor adjustment method is cumbersome to implement with latitude longitude. Ensure the zfactor is 1 because our x,y and z values are all in meters. By default, a grayscale color ramp is used to display a hillshaded elevation model.
Basic visualization of lidar digital elevation models using arcgis. The illumination source is considered to be at infinity. Create a hillshade raster of the base dem dem03, in this example using the spatial analyst tools. Convert the elevation units such as meters or feet to the horizontal coordinate units of the dataset, which may be feet, meters, or degrees. The zfactor is a conversion factor that adjusts the units of measure for the vertical or elevation units when they are different from the horizontal coordinate x,y units of the input surface. Using arcmap hillshade command to simulate 3 dimensional images. Open hillshade, hillshade window is appears select elevation layer and output layer, output format default is geotiff is ok, type z factor 300. Determine what the middle latitude of the area of interest is. It is not uncommon to perceive the output from hillshade as looking peculiar if the. The zvalues of the input surface are multiplied by the zfactor when calculating the final output surface. Pdf relief visualization techniques using free and open. If you add appropriate or correct zfactor to your dem while creating hillshade, you can avoid too much contrast in the hillshade and too much bumpy in the flat areas. The input dem is multiplied by the z factor before calculating shadows. Configure the options for rendering, then click apply hillshade.
I understand that the z value has to be converted to degrees using a z factor of. To calculate the shade value, first the altitude and azimuth of the illumination source are needed. The usgs hydrosheds program is in the process of deriving good. Arcgis has many useful tools for calculating slope, aspect, hillshade and curvature from dem rasters. The zfactor parameter is in many spatial analyst and 3d analyst tools. The arcgis software suite has many useful capabilities for handling geospatial data including. Hello, i have a question about z factors and how to use them within a slope analysis and hillshade function. Hillshadeslope analysis and z factors geonet, the esri. Home creating 3d visualizations in arcmap using hillshade.
The zfactor is a conversion factor that adjusts the units of measure for the. If the z units of the data being used are feet, first use the raster calculator to multiply the raster by the conversion factor 0. If the model shadows option is disabled unchecked, the output raster only considers local illumination angle. The zfactor adjusts the units of measure for the zunits when they are different from the x,y units of the input surface. The hillshade raster has an integer value range of 0 to 255. Hillshade one direction 315 degrees top and hillshade one direction 45 degrees bottom comparison of popular gis software by availability of blending modes colour hypsometric tint with two. This zfactor adjustment method is cumbersome to implement with latitudelongitude. Specific azimuth and altitude angles are set and a zfactor to convert z units in feet to meters.
If the x,y units and zunits are in the same units of measure, the zfactor is 1. It is the number of ground x,y units in one surface zunit. Generally, hillshade dems are clearer if the basic elevation layer is multiplied by 2 or 3. The zfactor is a scaling factor used to convert the elevation values for two purposes. Setting the z factor parameter correctly arcgis blog. Not setting the zfactor correctly makes the hillshades look heavy or leaden. Relief visualization techniques using free and open source gis tools. These values will be processed with calculations for slope and aspect to determine the final hillshade value for each cell in the output raster. X and y are in decimal degrees while z is in meters. The surface area and ratio arcgis extension enables you to generate raster datasets of surface.507 548 644 100 1459 1058 246 1422 578 745 337 356 1543 1208 818 870 896 1167 735 687 1227 1261 1094 401 238 652 753 643 233 795 979 786 1105 995 157