Exploring ILWIS software

Sry Handini Puteri
5 min readApr 24, 2023

ILWIS stands for The Integrated Land and Water Information System, a software that focuses itself on raster-based analysis. It is initially proprietary software, but it started to be open-source software in 2007. It has GIS and remote sensing power analysis to process vectors and rasters at the same time. This is my first time exploring the software. Hence, I just would like to share the impression and several functions that this software may have.

ILWIS is a software that is developed by ITC, University of Twente, where I am currently taking my master study. It has a wide range of features, as stated by its current license from 52°North, ILWIS has several functionalities of import/export, digitizing, editing, analysis, and display of data, as well as production of quality maps.

I think it has already a long-standing community users because I have heard of ILWIS since I was in my bachelor's. Now I am using version 3.8 and ILWIS intends to release its 4.0 version (soon). I understand that the current trend is more into scripting and automating stuff, but it might still be necessary for those who prefer a software with an interface to process some GIS stuff. This writing will be written from the perspective of a beginner.

Exploring ILWIS interface

I was given a dataset in zip format, covering many datasets of Risk City. The zip files consist of many files in the format that I am not familiar with, such as TBT File, TRI# File, DM# File, DOM File, MP# File, MPR File, MPS File, RP$ File, MPA File, and other formats. Then when I am opening the zip file from the ILWIS 3.8 version, the open button can direct us to the zip file extracted folder that opens all the file formats in its native functions.

ILWIS dataset GUI

There are many files within the folder, including the building map in 1997, flood hazard layer, contour, landslide inventory boundary, rivers, roads, DEM and etc.

On the left part of the GUI, there is an operation-tree that shows the available operation functions within ILWIS. It covers functions of image processing, import/export, interpolation, polygon operation, rasterize and etc.

The front interface of ILWIS and several functions on the left seen in the left panel

There are many icons provided for each file. For exploration purposes, I will check the Landslide_ID file. There are three different files consisting of three items, the attribute table, the raster, and one domain identifier file. What I realized, the table attribute is stored in a different file. Unlike other GIS software, where the attribute table and the identifier are embedded into one single shapefile.

Three different files explaining one single feature

If we opened the attribute table file, then the display will consist of the row and column for each ID stored in the file. The picture is shown below. The nice thing, there is a short summary of the table already displayed at the bottom of the table. There is a Min, Max, Average, Standard Deviation, and Sum. So, we do not need to have extra effort to see the summary of the dataset.

The attribute table of Landslide_ID

The distribution of the Landslide_ID can be seen from the raster icon. The result can be seen below.

Vector display for the landslide inventory

The distribution of the vector can be seen from another icon, which looks like a polygon division. Each time we click on the polygon, the details of the polygon will display at the bottom left of the window. The downside is, the file of the attribute does not really connect with the polygon file. There is no highlight or zoom to layer function just like what we have on a QGIS or ArcGIS.

Attribute and polygon files opened simultaneously to see whether the data is ‘connected’

The last file is the domain identifier. I am not really sure how to use this file. I think this is the place where each polygon ID is stored.

Domain identifier

Testing interpolation function from the contour file in ILWIS

Just to check, I have a contour file embedded in the zip file. Then I would like to test the interpolation function available in the operation-tree of ILWIS.

Contour file
Interpolation functions

We filled in the necessary data. The contour map refers to the contour files. We define the name of the output raster map. The georeference filled in the coordinate system (I guess). The name is ‘Somewhere’. I am not sure how it works, but somehow it is a given dataset. The domain is the type that we are working on. If it is numerical data, it can be set as ‘value’. If we are working with a raster, we can choose ‘byte’ to make sure it is processed from 0–255 (8 bit).

Contour interpolation feature

Then, this is the result of the contour processing.

Contours processed from the contour line
The result from the contour line to interpolated contour value



Sry Handini Puteri

Personal learning space ; A Geoenthusiast ; Interested in Disaster Risk Management