LITAP

Landscape Integrated Terrain Analysis Package (LITAP)

LITAP is a software package aimed at providing open access code for terrain analysis and landscape and hydrology models built on terrain attributes. A major component of LITAP is founded on R. A. (Bob) MacMillan’s LandMapR suite of programs for flow topology and landform segmentation analyses with extended new parameters and methodologies developed by Drs. Sheng Li and Steffi LaZerte. Another component of LITAP focuses on the calculations and uses of directional terrain attributes developed by Dr. Sheng Li. This project is actively under development and we plan to add more features to support modelling of surficial hydrology, soil erosion, landscape zoning, hydrologic response units and buffer zone delineation.

LITAP is a project funded by Agriculture and Agri-Food Canada and directed by Dr. Sheng Li.

See articles for new features specific to LITAP (coming soon)!

Currently LITAP includes major functions

• flow_mapper() - based on FlowMapR
• form_mapper() - based on FormMapR
• facet_mapper() - based on FacetMapR
• wepp_mapper() - based on WeppMapR

See the companion website for more details: https://FRDC-SHL.github.io/LITAP/

Installation

Use the remotes package to directly install R packages from github:

install.packages("remotes") # If not already installed
remotes::install_github("FRDC-SHL/LITAP") 

Example files

LITAP comes with several example files (testELEV.dbf, testELEV_mini.dbf, arule.dbf, and crule.dbf). These are found in the “extdata” folder inside the LITAP package folder. If you are unsure where this folder is, use the function system.file():

system.file("extdata", package = "LITAP")

Now you can copy and paste these files to your working folder to try out the following examples.

Basic Usage: Overall

flow_mapper(file = "testELEV.dbf", nrow = 90, ncol = 90, grid = 5, out_folder = "Output/")
form_mapper(folder = "Output")
facet_mapper(folder = "Output", crule = "crule.dbf")
wepp_mapper(folder = "Output")

Basic Usage: flow_mapper()

Load the package:

library(LITAP)

## LITAP v0.7.0
## LITAP is still in development; Help us by submitting bugs/feature requests: 
## http://github.com/FRDC-SHL/LITAP/issues

First, specify the dem file and the number of rows and columns, as well as the grid size, if it’s not inferable from the data.

flow_mapper(file = "testELEV.dbf", nrow = 90, ncol = 90, grid = 5)

Can also specify pit removal parameters:

flow_mapper(file = "testELEV.dbf", nrow = 90, ncol = 90, grid = 5, 
             max_area = 5, max_depth = 0.2)

As well as the location of output files:

flow_mapper(file = "testELEV.dbf", nrow = 90, ncol = 90, grid = 5, out_folder = "Output/")

## CALCULATING DIRECTIONS

## CALCULATING WATERSHEDS

## REMOVING INITIAL PITS

## CALCULATING POND (GLOBAL) WATERSHEDS

## CALCULATING FILL PATTERNS

## INVERTING DEM

## CALCULATING INVERTED DIRECTIONS

## CALCULATING INVERTED WATERSHEDS

## REMOVING INVERTED PITS

## CREATING REPORT

## Run took: 0.28 min

Basic Usage: form_mapper()

form_mapper() uses output from flow_mapper() and requires a grid size.

form_mapper(folder = "Output/")

## SETUP

## CALCULATING FORM

## CALCULATING WETNESS INDICES

## CALCULATING RELIEF DERIVITIVES

## CALCULATING SLOPE LENGTH

## Run took: 0.02 min

Optionally, users can also define channels and ridges according to the number of up-/down-slope cells that flow through the cell in question.

form_mapper(folder = "Output/", str_val = 10000, ridge_val = 10000)

Basic Usage: facet_mapper()

facet_mapper() uses output from flow_mapper() and form_mapper() and requires a CRULE file and, optionally, an ARULE file.

facet_mapper(folder = "Output/", crule = "crule.dbf", arule = "arule.dbf")

## Using buffer of 4 rows ('edge_row') and 4 cols ('edge_col') per side

## Formatting arule file

##   - Renaming 'slope' to 'slope_pct'

## Formatting crule file

## 

## CALCULATING FUZZY ATTRIBUTES

## CALCULATING CLASSES

## CREATING SUMMARY TABLES

## Warning: Skipping Topographic Summary...
##   This step requires a facets output file `dem_fuzc` with facets 'cst', 'ups', 'mid', 'low', 'dep,
##   as well as a topographic_derivatives.xlsx file.
##   Use `facet_mapper()` with a `crule` file defining the relevant facets and *no* `arule` file.

## Run took: 0.05 min

If an ARULE file is not provided, LITAP will derive the rules based on the input files (as in Li et al. 2011, Canadian Journal of Soil Science 91(2), 251-266). The derived A rules will be output to “afile_derived.csv”.

facet_mapper(folder = "Output/", crule = "crule.dbf")

Basic Usage: wepp_mapper()

wepp_mapper() uses output from flow_mapper()

wepp_mapper(folder = "Output/")

Optionally, users can also define the maximum length of channel cells (after which they will be split into separate segments), as well as the upslope threshold to define channel cells

wepp_mapper(folder = "Output/", chan_length = 500, upslope_threshold = 500)

Multiple file types

LITAP accepts multiple file types and can automatically assess the number of rows and columns, depending on the type (see ?load_file for details and requirements):

flow_mapper(file = "testELEV.csv")
flow_mapper(file = "testELEV.grd")
flow_mapper(file = "testELEV.flt")

Output

Output files can be .csv or .rds (R data files) in the output folders “flow”, “form”, “facet” and “wepp”. Additionally, an html report summarizing the flow_mapper() run is included in the output folder (testELEV_final_report.html).

See the LITAP website for more details and examples