# How to calculate an Illumination raster for fire ignition danger analysis?

I am doing a fire ignition danger analysis using this equation that I found in Millington (2012) http://www.jmecology.com/wp-content/uploads/2014/03/33-42-MILLINGTON.pdf

`IR = 4H + 3V + 2I – E`

Where:

``````H = human presence (i.e. within 30m of a road/trails)
V = vegetation
I = Illumination
E = Elevation
``````

It is based in another paper by Salas and Chuvieco (1994) that I couldn't find. My problem is the illumination raster. I found another link where they give some guidelines in how to create it, but I have not found any other reference. http://ibis.geog.ubc.ca/courses/geob370/students/class06/fire/mce.html

Do you know where can I find information related to how to create this raster?

• Welcome to GS@SE. You are more likely to get a useful answer if you specify what software you are using. – Mark Cupitt Sep 6 '14 at 8:23
• Thanks. I am using ArcGIS 10.2.1, but I am open to use any other software especially if it's open source. – Ernesto561 Sep 6 '14 at 12:51
• The second link you provide walks through the illumination raster process pretty thoroughly. Can you be more specific in your question: do you need to know what tools to use for a particular step? are you unsure how to calculate the solar altitude and azimuth? – Erica Sep 6 '14 at 15:05
• Thanks for your answer. I would like to find a more solid reference, which shows for example the criteria in what day to use (I think it should be the hottest summer day) and more theory about it. I think the procedure is well explained, just need to use the Hillshade tool and the raster calculator. I have looked for innformation and I haven´t found any other reference about how to create an illumination raster. By the way, it seems that GRASS GIS has a function, (r.sun) but I am not sure if it is the same procedure that it is explained in the second link. – Ernesto561 Sep 7 '14 at 0:08
• @Ernesto561 I would think that the Solar Analyst will provide the exact illumination data that you are looking for. Why don't you provide an answer to your own question? – WhiteboxDev Oct 3 '14 at 0:31