iTree Canopy
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iTree Canopy
Is there a recommended study area size limit/threshold when using iTree Canopy? I recently completed a project for a neighborhood and now I'm considering using Canopy to analyze the entire city. The neighborhood is approximately .3 square miles in size and the city is 43 square miles.
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- i-Tree Team
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Canopy Study Area Size Limitations
The study area size actually does not have much of an effect on how canopy functions. The only real limitation that I see is that in a really small study area (like a single residence or less than a couple acres) the resolution of the images used may become an issue.
The main concern is that your estimates are as precise as you need them to be. This means that the errors bars around the estimates get as small as you want them to be. The size of your area actually doesn't have any effect on this precision. The only things that affect precision are how many points you use in your sample and how much variability there is in the cover types you are estimating within your area of interest.
You can check to see how the values are calculated in Canopy in this document (http://www.itreetools.org/canopy/resour ... dology.pdf). You will notice that area is not included in any of those calculations. As indicated at the bottom of the i-Tree Canopy application page (http://www.itreetools.org/canopy/index.php) we generally recommend 500-1000 survey points regardless of the size of the area sampled. Also, the more cover type categories you use the more survey points you will need.
The main concern is that your estimates are as precise as you need them to be. This means that the errors bars around the estimates get as small as you want them to be. The size of your area actually doesn't have any effect on this precision. The only things that affect precision are how many points you use in your sample and how much variability there is in the cover types you are estimating within your area of interest.
You can check to see how the values are calculated in Canopy in this document (http://www.itreetools.org/canopy/resour ... dology.pdf). You will notice that area is not included in any of those calculations. As indicated at the bottom of the i-Tree Canopy application page (http://www.itreetools.org/canopy/index.php) we generally recommend 500-1000 survey points regardless of the size of the area sampled. Also, the more cover type categories you use the more survey points you will need.
Last edited by Jason.Henning on Tue Jun 18, 2013 11:56 am, edited 1 time in total.