AKgeomorph

AKgeomorph is a Python package that contains functions for calculation of geomorphology metrics for Alaska.

Author: Timm Nawrocki, Alaska Center for Conservation Science, University of Alaska Anchorage

Created On: 2023-10-10

Last Updated: 2024-05-04

Description: Functions for calculating topographic and hydrographic metrics for modeling or descriptive purposes.

Getting Started

These instructions will enable you to import functions from the AKgeomorph package into scripts. This package depends on an installation of ArcGIS Pro 3.1+ and therefore must be installed into the bundled Python installation. A Spatial Analyst (sa) license is required to run the functions.

Prerequisites

1. Python 3.9+
2. pip
3. arcpy
4. datetime
5. time

Installing

To install the AKgeomorph package, use the pip install command below from the Python console of the ArcGIS Pro Python 3 installation.

pip install git+https://github.com/accs-uaa/akgeomorph

Usage

This section describes the purpose of each function and provides details of parameters and outputs.

Functions

calculate_aspect

The calculate_aspect function is used to calculate the aspect in degrees from North Pole perspective using geodesic azimuths and a quadratic estimator.

Parameters that must be modified:

• area_input: a raster of the study area to set snap raster and extract area
• elevation_input: an input 32-bit float elevation raster
• aspect_float: a file path for an output 32-bit float aspect raster in degrees
• aspect_output: [optional] a file path for an output 16-bit integer aspect raster in degrees (set to None if no output is desired)

Example

calculate_aspect(area_input, elevation_input, z_unit, aspect_float, None)

Credits

Authors

• Timm Nawrocki - Alaska Center for Conservation Science, University of Alaska Anchorage

Usage Requirements

Usage of the scripts, packages, tools, or routines included in this repository should be cited as follows:

Nawrocki, T.W. 2024. AKgeomorph. Git Repository. Available: https://github.com/accs-uaa/akgeomorph

The functions in the AKgeomorph package derive from previous work by Evans et al. (2014). Therefore, please also cite:

Evans, J.S., J. Oakleaf, S.A. Cushman, and D. Theobald. 2014. An ArcGIS Toolbox for Surface Gradient and Geomorphometric Modeling, version 2.0-0. Available: http://evansmurphy.wix.com/evansspatial.

Roughness

If using the roughness, please cite:

1. Riley, S.J., S.D. DeGloria, and R. Elliot. 1999. A terrain ruggedness index that quantifies topographic heterogeneity. Intermountain Journal of Sciences. 5. 1-4.

Surface Area Ratio

If using the surface area ratio function, please cite:

1. Pike, R.J., and S.E. Wilson. 1971. Elevation relief ratio, hypsometric integral, and geomorphic area altitude analysis. Bulletin of the Geological Society of America. 82. 1079-1084.

Topographic Wetness Index (Compound Topographic Index)

If using the topographic wetness index function, please cite:

1. Gessler, P.E., I.D. Moore, N.J. McKenzie, and P.J. Ryan. 1995. Soil-landscape modeling and spatial prediction of soil attributes. International Journal of GIS. 9. 421-432.
2. Moore, I.D., P.E. Gessler, G.A. Nielsen, and G.A. Petersen. 1993. Terrain attributes: estimation methods and scale effects. In: Jakeman, A.J., and M. McAleer (eds.). Modeling Change in Environmental Systems. Wiley. London, United Kingdom. 189-214.

Heat Load Index

If using the heat load index function, please cite:

1. McCune, B., and D. Keon. 2002. Equations for potential annual direct incident radiation and heat load index. Journal of Vegetation Science. 13. 603-606.

License

MIT