This page gives a quick  introduction on how to install and operate the iLand software. The content of this page is also part of the download package.

 

Installing iLand

The downloaded iLand package contains:
  • The executable (iland.exe) and the required library files (QtCore4.dll, QtGui4.dll, QtScript4.dll, QtSql4.dll, QtXml4.dll, libgcc_s_dw_2-1.dll, mingwm10.dll) for running iLand on Microsoft Windows (XP, Vista, Windows 7).
  • An extensive example for running the model "out of the box" in the “example” folder. 
  • The full source code of iLand is packed in the “src.zip” file. 
To install iLand, simply extract the ZIP folder to a location of your choice und start the model by double clicking the “iland.exe” file. iLand comes without a dedicated installer and does not modify the Windows registry. It is thus also possible to run iLand from a USB stick.
iLand is written in C++ and uses the cross-platform toolkit Qt. Therefore iLand can in principal also be used on Linux and Mac platforms. We have already (successfully compiled and employed iLand also on a Linux machine (usually Ubuntu). Macs should work as well, but we actually never tried running iLand on a Mac yet (see also the building instructions below).

Running iLand

iLand organizes its inputs and outputs in so-called “projects”. A “project” is a set of folders containing different kinds of data (e.g. climate data or species parameters) and a “project-file” (http://iland-model.org/project+file), which is a XML-file acting as the main controller for the various model  options. 
In order to run simulations with iLand you need to (see also Figure 1):
  • Start The iLand viewer (iland.exe) (see also http://iland-model.org/iLand+Software) 
  • Select  a project file (1)
  • Create the model (2). This sets up the model landscape and initial trees.
  • Run the model (3). Enter the number of years you want the model to run.

  • While the model is running (there is also a “Pause” button), you can view different types of data in the GUI visualization:

    • “Light influence field”: This is the “LIF” (http://iland-model.org/competition+for+light). Red means low, blue high light levels. Spatial resolution is a 2m grid.
    • “dominance grid”:  Maximum tree heights at 10m resolution
    • “Individual trees” shows tree crowns from bird’s eye perspective (i.e. as stylized circles with the radius indicating the size of the tree). The color indicates the light resource index (again, red means low LRIs, see http://iland-model.org/competition+for+light)
    • “resource unit” show the resource units, i.e. a 100m grid used for the calculation of e.g. the water balance. (http://iland-model.org/resource+units)
    • Clicking on a tree and a resource unit, respectively, shows their attribute in the “Data” box in the lower right corner. You can enter mathematical expressions (http://iland-model.org/expression) using these variables in the „expression“ field to visualize various aspects (e.g. “dbh” or “dbh*dbh/4*3.141592” to calculate basal area)
  • The log area (4) contains messages from the model. This kind of log info is especially helpful to track configuration or model errors.
  • The non-visual outputs of the model are stored in an output database (http://iland-model.org/Outputs). See http://iland-model.org/Software+Tools for tools helping to access the SQLite databases iLand uses to store simulation results in (it is also quite easy to read these databases into R for further analysis).
Figure 1. Main window of iLand at startup
 

Building iLand from source

The download package contains also the full source code of the model as a ZIP archive “src.zip”.  In order to be able to modify and compile iLand for yourself, you will need Qt and the QtCreator IDE. Both packages are freely available at http://qt.nokia.com/downloads. The shipped release is compiled with Qt 4.6 (mingw) but we expect no problems when using more recent versions of Qt (e.g.  4.8). 
After installing the Qt Creator IDE, open the “iland.pro” project in the “src/iland” folder (be sure to preserve file paths when extracting the source code). iLand uses no external libraries (except the Qt libraries) which should simplify the building process considerably – a click to “build” should suffice.