![]() They are automatically formatted this way when you type your code in the Python window or another coding environment. Quotation marks in Python are always straight (as opposed to slanted). Both print("GIS is cool") and print('GIS is cool') are therefore correct, but print("GIS is cool') results in an error. Python uses both single and double quotation marks to identify strings, provided they are used consistently. You create a string by enclosing the characters in a pair of quotation marks. A string in Python consists of a sequence of characters. Most functions in Python have arguments or parameters, which are provided in parentheses following the function. A function in Python carries out a specific task. See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.In this line of code, print() is a function. The GPU processing with Spatial Analyst help topic includes details for configuring and working with GPU devices, as well as troubleshooting tips. This tool can be GPU accelerated when calculating geodesic slope, which means that if a GPU device (graphics processing unit) is available on your system, it will be used to enhance the performance of the geodesic method. Using a larger neighborhood can also better represent landforms and surface characteristics when using high resolution surfaces. Using a larger neighborhood can minimize the effect of noisy surfaces. If the Input raster parameter value ( in_raster in Python) is high resolution with a cell size of less than a few meters, or particularly noisy, consider using the Surface Parameters tool and its user-defined neighborhood distance option instead of the immediate 3 by 3 neighborhood of this tool. An example of when an input raster may be resampled is when the output coordinate system, extent, or cell size is different from that of the input. When the input raster needs to be resampled, the bilinear technique will be used. If it is undefined, meter will be used by default. You can use the Define Projection tool to specify a z-unit. It is recommended that you define a z-unit for the input raster if it is missing. If a z-unit is available in the vertical coordinate system of the input raster, it will be applied automatically. ![]() The Z unit parameter will be enabled only when the geodesic method is selected. The Z factor parameter will be enabled only when the planar method is selected.įor the geodesic method, specifying the surface z-unit is important to ensure the accuracy of the output. A flat surface is 0 percent, a 45 degree surface is 100 percent, and as the surface becomes more vertical, the percent rise becomes increasingly larger.įor the planar method, the use of a z-factor is essential for correct slope calculations when the surface (vertical) z-units are expressed in units different from the ground x,y units. For percent rise, the range is 0 to essentially infinity.For degrees, the range of slope values is 0 to 90.The range of values in the output depends on the type of measurement units. This is because along the boundary of the input dataset, those cells do not have enough valid neighbors. The cells in the outermost rows and columns of the output raster will be NoData. If there are fewer than seven valid cells, the calculation will not be performed, and the output at that processing cell will be NoData. Of the eight cells neighboring the processing cell, this tool requires that at least seven of them have a valid value. If the processing cell is NoData, the output for that location will be NoData. This tool uses a 3 by 3 cell moving window to process the data. You can continue to use the traditional approach of the Slope tool if you need your results to exactly match previous tool runs or if fast execution time is more important than a better algorithm. This can be useful with gradual homogeneous terrain interrupted by streams, roads, or sharp breaks in slope. Surface Parameters also provides an adaptive window option that evaluates the local variability of the terrain and identifies the largest appropriate neighborhood size for each cell. ![]() Larger window sizes are useful with high resolution elevation data to capture land surface processes at an appropriate scale. The Slope tool uses a 3 by 3 window of cells to compute the value, while the Surface Parameters tool allows window sizes from 3 by 3 to 15 by 15 cells. The Surface Parameters tool fits a surface to the neighborhood of cells instead of a plane, which provides a more natural fit to the terrain. The Slope tool fits a plane to the nine local cells, but a plane may not be a good descriptor of the landscape and may mask or exaggerate natural variations of interest. The Surface Parameters tool provides a newer implementation of slope and is recommended to be used instead of the Slope tool.
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