LoCoH is available for GIS users in two forms:
- ArcGIS 9.x users can download and install the LoCoH for ArcGIS toolbox. Once installed, a new tool appears in the ArcToolbox window in ArcMap. The toolbox uses the same R script that is found in the Adehabitat library and powers the web application, hence R must also be installed on the machine. See below for installation instructions.
- ArcView 3.x users can download an extension to create k-NNCH utilization distributions. This extension is not written in R, but has many of the same options as the R script.
- Note these applications are designed to analyze data sets containing two dimensional points. If you have three dimensional data sets, take the planar projection of the points.
Installing the LoCoH Toolbox
In order to use the LoCoH toolbox you must have first installed R and some additional libraries on your system. First, download R:
Once you've gotten your hands on R, you need to install a number of R libraries. These libraries are: ade4, adehabitat, shapefiles, and gpclib. To install them, just open up R and enter the following:
install.packages(c("gpclib","ade4","adehabitat","shapefiles"), dependencies=TRUE, repos="http://cran.cnr.berkeley.edu/")
Additionally you need the R(D)COM server application which lets ArcToolbox communicate with the R environment. There are multiple versions of the R(D)COM server, I used the RSrv200.exe version.
Download R(D)COM Server
Lastly you will need to download the LoCoH toolbox itself.
Download the LoCoH Toolbox
Once you have downloaded and unzipped the toolbox, you can load it into ArcMap. Follow these instructions:
- Open ArcMap
- If it is not already open, open the Toolbox Panel by clicking on the red, toolbox icon.
- Then, right-click on the panel and select 'Add Toolbox'.
- Navigate to where you saved the LoCoH toolbox and select the locoh.tbx file, it will have a red toolbox icon.
- Click 'Open' to install the toolbox. Do not double click the toolbox, that will not install it.
- Now the LoCoH toolbox will appear in your toolbox pane. You're ready to go!
To make this toolbox permanent, right-click on the toolbox pane, click "Save Settings..." and then "To Default".
Important: Arc software can have issues with directory paths with lots of characters. If you get strange errors, try moving the toolbox into your C drive.
Need more help? Use the:
PDF Troubleshooting Guide
Using the Toolbox
The toolbox contains its own documentation that details how it is used. Operation is simple. Just download it and give it a spin to see for yourself.
Basic operation consists of:
- Double clicking on one of the three LoCoH scripts.
- Selecting a shapefile using Arc's selection dialog.
- Setting your value of k, r, or a and how to handle duplicated points.
- Using Arc's dialogs to decide where to save data.
- And clicking 'OK'!
Note: The LoCoH algorithms, are complex and take a long time to compute. Depending on computer speed and memory resources, times taken can very. On a 3GHz, 1GB of memory machine, a data set of 4,000 points took us four hours to analyze.