Citywide Site Survey using TamoGraph
I recently had the opportunity to perform a large site survey. It was a lot of fun and a little out of the ordinary. I am writing this little blog article to talk about what was different and how I dealt with some of the challenges I have faced.
The area to be surveyed was about 27km² large. This is the side of a small city. This is a tiny bit larger than the floor plan I am usually dealing with!
I used the program TamoGraph Site Survey to perform the site survey. Concerning the map, I wanted to have a good enough quality of image so when I would zoom in into a specific street, I could actually read the name of the street on the map. So I needed a map with enough details. This was my first challenge.
Getting a detailed map of the area
If you go on Google Maps and you zoom out in order to be able to visualize the whole area you need to survey, you are not going to have enough details. You usually only see the name of the main streets. This does not provide enough details for you to perform your work efficiently. Moreover, any time you are going to try to zoom in, everything is going to become blurry and you won’t be able to work with what you have.
For me, the solution was to use the following method:
- I used the tool called WebShot to download the high quality images corresponding to the area I needed to study from Google Maps. Usually WebShot is able to merge these images back together to provide you with the full high quality image. However, in my case, the area was just too big and the program was not able to handle it.
- So, I used Adobe illustrator to merge all the high quality images.
I ended up having a large image that I could zoom into with all the details needed:
Large survey file in TamoGraph
I was able to used this map to create the project in TamoGraph. I calibrated the map using GPS coordinates that I would get from Google Maps and I was good to go.
Since the area was way to big to survey in one time, I decided to divide the area into multiple smaller areas (47 in total) and I created a different survey file for each of them. My idea was to export the survey data from these smaller projects and import them back into the large project at the end.
After talking with the support team over at TamoSoft, it is actually easier (and a better idea too) to copy the gloabl survey file many times (47 times in my case), and start from this global survey file for the smaller surveys. Even if you are only surveying a small area. It is easier to merge all the collected data at the end.
To divide the area into smaller ones, I used Google Earth Pro to draw the survey paths. Using the path ruler tool, I was able to keep the survey paths under 10km long. I ended up with the following survey paths:
I created survey path 5km to 10km long so my surveys would actually take between 30mins to 60mins to get completed. I was driving around the city at a speed of about 15km/h to 20km/h. Since I was driving slow and I didn’t want to disrupt the traffic, I was performing my surveys by night.
It took me 5 days (nights I should say) to cover about 300km of roads.
In terms of equipment, this is what I used:
- Laptop (MacBook Air 13)
- Tamograph Site Survey installed on a Windows 8 VM (VMWare Fusion)
- GPS Receiver: USBlobalsat BU-353-S4
- 802.11 USB adapter: 3x Edimax EW-7822UAC
- Spectrum Analyzer: Wi-Spy dBx
- A car power inverter so I could keep my laptop plugged in
Analyzing the collected data
In order to analyze the data collected, I couldn’t really used the whole map. I would not get the level of details I wanted and It was visually not explicit to do it this way.
So I decided to divide the area again for analysis. This time, I divided the whole area into 17 smaller parts.
I articulated my reports around these 17 parts. For each part, I was analyzing the collected data like I would normally do for any other site surveys.
Working on this project was a lot of fun for me. If you need to survey a large area one day, don’t hesitate to ask me any questions. I will be happy to share my experiences with you.