# GIS Help For School Project (Cellphone Signal Modelling)

Question asked by sammtclf on May 30, 2015
Latest reply on May 30, 2015 by Dan_Patterson

Hey guys, as previously mentioned I'm doing a project in school using ArcMAP model builder, for a self-chosen and directed project. It's a relatively small project, so significant assumptions to simplify the process and a relative amount of error is accepted.

Basically what we are doing is modelling where you would get cellphone reception in areas of New Zealand wilderness areas, in particular around popular hiking trails.

We managed to get the following data which we will use for our model:

-Shape file showing points where transmission towers are and the corresponding strengths.

-Shape file of all Department of Conservation (DOC) hiking tracks in New Zealand

-A Digital Elevation Model of New Zealand (8m resolution)

We have managed to find a rough estimate of signal strength by using euclidean distance tool on the transmission towers file. The signal strength is found by:

``Distance from the tower x the decay rate x tower strength. ``

This works well, and we have a raster map of corresponding signal strengths for the area.

Now we need to somehow find a way to account for the topography of the region. As relatively new users of GIS we are pretty unsure how to do this and were hoping maybe some of you could help?

We are thinking we'd make the assumption that if an area is in the line of sight of tower, this signal is as original otherwise there is no signal. We will ignore vegetation.

Essentially we would like to calculate a raster grid map of small areas which show if the areas is in the line of site of a transmission towers (and within a certain specified distance if possible), or if they are not. Any ideas on how to do this?

Ideally this line of sight map would be found in logical values (in line of sight - value=1, out of sight - value=0)

I was thinking once I had this line of sight map I could multiply it with the signal strength map to get a new signal map that accounts for topography.