Concerned that the roof diagram lines in your sketch order don't seem to follow the picture exactly? Don't worry--this does not mean your measurements are inaccurate!
While it seems logical to trace the edges of a roof exactly, aerial imagery is not always captured directly over the center of a structure which can lead to visual distortion in the image.
For example, compare the images below:
A B C
A) The first image was clearly taken way off from the center of this house. You can see a lot of the siding on the right side of the structure and the gable in the front looks larger on one side, even though we know in real life it would be symmetrical.
B) The middle image is much better but still slightly offset, as you can see a bit of siding on the left. This leads to the front gable again looking larger on one side.
C) The third image shows no siding so we can assume there is minimal visual distortion, but there could still be some distortion present.
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With the inherent risk of visual distortion that is present with any remote measurements from any source, tracing the roof lines exactly as they appear in a picture could lead to inaccurate measurements. Instead, best practice is to sketch the roof using straight lines and 90 degree angles, even if lines don't follow the picture exactly. Essentially, we want to draw the roof as it appears in real life, rather than how it appears in an image.
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Look at the sketch below. While the lines are offset from the image, notice that the measurements themselves reflect symmetry and equal proportions:
The largest ridge line was pulled off-center in order to ensure all three hip lines were equal at 31.5ft. The ridge line in the front left section was pulled off-center to ensure the small hips match at 7.1ft and the rakes match at 8.4ft. Finally, the dormer in the front has a slightly off-center ridge to ensure the valleys match at 8ft each.
NOTE: RoofSnap, like all remote measurement companies, suggests that you verify measurements (or at least pitch) on-site before signing any contracts or ordering materials for a job.
If you have additional questions about order accuracy or best practices for sketching, please reach out to our Support Team or give us a call at 877-766-3762!