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Measure points in aerial photos

This process sounds long, but isn't bad, really. Note that it is not the same method as normal Nature Score data: instead of each datapoint being a percentage of nature in an area, it gives yes/no measurements. But by combining a lot of yes/no measurements and averaging them, you get a percentage score just like a normal Street Nature Score, and we can integrate it into our database.

Download the .shp file ("shapefile") for the neighborhood of your choice by right-clicking and choosing "download": Downtown Seattle, Capitol Hill, Central District, South Lake Union, Fremont. (If you want to measure a different area, email streetnaturescore [at] gmail [dot] com for directions on making your own shapefile.)

In your web browser, go to http://www.itreetools.org/canopy/index.php. The website will say "i-Tree Canopy" and show a satellite / aerial photo map on the left.

• Click the "Load ESRI Shapefile" button; it will pop up a license agreement; click "Accept".

• In the file browser that pops up, choose your .shp file to upload. When it has uploaded properly, the satellite map on the left will change to be your chosen location, with a red line drawn around the street or neighborhood you will measure points in.

• On the main i-Tree Canopy screen, click "Configure Survey".

• In the window that pops up, click "Done".

• Click "Begin i-Tree Canopy Survey". A white graph will appear, blank, with grey bars underneath saying "Cover Class | Latitude | Longitude". In the lower left corner of the grey bars, under the letters "Id", is a "+" sign. Click that to create a new sample point.

• The map will zoom to the new point and show a yellow cross-hairs. If that cross-hairs points to nature of any kind (trees, grass, shrubs, even a body of water or a beach), verify that the pull-down menu under "cover class" says "tree". If it points to hardscape (street, building, car, anything not nature), make sure the pulldown menu says "non-tree". You have just measured that point.

• Click the "+" sign to measure another point. The map will again zoom to that point, and you will again choose whether the point is nature or hardscape. This is you measuring the nature score! You'll notice the white graph on the right now has dots and blue error bars. As you keep measuring, the values will change. The dot above "T" is the nature score.

• Repeat this measurement of nature / hardscape for 100-200 points. (200 points should take about an hour. The more points the better!) If you're not sure about a point (for instance, if the crosshair was hitting the edge of nature / non-nature), just decide and measure two more points, there's no need to dwell on it. You can measure as many additional points as you want. The more points the better!

• When you're done measuring points, click "Export" above the aerial photo. It will download a file called "canopy.csv".

• Rename the file to be the name of the .shp file you used earlier, plus the nature score and uncertainty. To get the nature score and uncertainty, look at the graph of two dots under "Percent Cover". The number and the uncertainty value listed above the left point (under the words "i-Tree" and above "T" and "Cover Class") is the one you want. Your filename should be something like "Downtown score 4.5 +-3.5.csv".

• Email the .csv file to streetnaturescore [at] gmail [dot] com.

• You're done! Your data will be added to the map as soon as we can.