I am trying to convert a slope raster to a friction surface with values based on Tobler's Hiking Function in ArcGIS Pro, but I get an error message I am not sure is about the formula syntax or file/path names. I first converted a DEM of part of the Florida coast with a 5-meter cell size and elevation units in centimeters to a slope raster with a Z-factor of 0.01 because I believe I had to convert centimeters (vertical units) to meters (horizontal units). When the Z-factor was 1 most of the land, including the coastline, had values greater than 45 degrees. Other than roads and reservoirs the slope raster is very flat but I would expect that for Florida.

 ERROR 000539: Traceback (most recent call last):
  File "<expression>", line 1, in <module>
  File "<string>", line 8, in rcexec_DC684390_0C54_4F14_9EBF_B34DF3F2E1B1
RuntimeError:  ERROR 010240: Could not save raster dataset to cm5_fl7_hike.tif with output format FGDBR.
 Failed to execute (RasterCalculator).


Map algebra expression:  (5.0 / 1000) / (6 * Exp(-3.5 * Abs(Tan(("DEMs\5M\cm5_fl7_slopem.tif" * 3.14159) / 180) + .05))) 

Output raster: d:\FLGIS\Lidar\Lidar.gdb\cm5_fl7_hike.tif

I am trying to replicate the following mathematical formula which was typed exactly as it was written in an article guideenter image description here

  • 1
    You can't have an extension on a file geodatabase raster. It's either TIFF in a folder with an extension or a geodatabase raster without an extension. Oct 7, 2020 at 6:00
  • It's wrong to use formula like that, because slope can be both positive and negative, read on vertical factor. E.g. gis.stackexchange.com/questions/190144/…
    – FelixIP
    Oct 7, 2020 at 6:26
  • Can I change the RC formula or should I use another tool? After trying to replicate the PDBL in your link I get nine "Error: Initialization failure in distributed distance operation." Does it have to do with using 21 points for my feature source data? Oct 8, 2020 at 0:25

1 Answer 1


When creating raster data in geodatabase, you do not need to add file extension such as .tif. This a mentioned in the help of Create Raster Dataset:

When storing a raster dataset in a geodatabase, do not add a file extension to the name of the raster dataset.

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