Is there a way to to see if Landscape orientation better before doing a site visit?

[Hookipa]

Aloha,
I am curious to know if anyone can tell me if there is a way to pre-determine if landscape orientation would be better instead of portrait using just a sat. image. Like is a roof has a long run but short ridge?

-Mahalo in advance for any advice!

[SunEagle]

I would think that there might be more racking with a landscape then protrait layout based on the size of the panels and the amount they would flex if you spaced the connection point too far apart.

Each layout would be different based on shading or roof penetrations like vent pipes. I would also think that wind loading and attachments to the roof structure might come into play.

[sesmarvel]

Hi,

I suggest you go to the Google Earth pro and check if you can see the roof on the site. It's also advisable to get the 'as built' drawings (especially the roof plan which might indicate MEP equipment if there's any) from the client and from there you can see if portrait or landscape orientation of the panels will be feasible.

Cheers.

[Hookipa]

Aloha,
Thank you for your reply, I think i asked the question wrong. I was wondering if there was a way to determine from a sat. image is landscape would be a better option than portrait before a site visit is done.

[bcroe]

Aloha,
I am curious to know if anyone can tell me if there is a good time to use landscape orientation instead of portrait. I ask because my sales team regularly sells deals in portrait but sometimes during the site visit we find out more can fit on certain roofs in landscape. We then have to go back and do paperwork and add additional costs which sometimes is bothersome.
Is there a way to look at a sat. image of a roof and determine from that if landscape will be better? Does a longer roof run compared to shorter ridge mean anything?

-Mahalo in advance for any advice!

If you have snow, landscape means the snow doesn't need to slide or be pulled nearly as far to clear the panel. Of course that
implies a gap between panels for the snow to fall through. This may only work well on ground mounts, where several small
piles of snow are much less likely to block than one big pile at the lower edge. Bruce Roe

[Hookipa]

Aloha,
Thank you for your reply. I am in Hawaii so no snow

[SunEagle]

If you have snow, landscape means the snow doesn't need to slide or be pulled nearly as far to clear the panel. Of course that
implies a gap between panels for the snow to fall through. This may only work well on ground mounts, where several small
piles of snow are much less likely to block than one big pile at the lower edge. Bruce Roe

I believe the OP is somewhere in Hawaii or the Islands so snow is probably not on the radar.

[philips]

Mauna Kea can get snow, probably good for solar up there too with nice clear skies.

[J.P.M.]

Mauna Kea can get snow, probably good for solar up there too with nice clear skies.

Probably for a first estimate to estimate max. available area and dimensions, but an actual measurement will still be necessary for design to confirm and check for things like vents, condition of roof etc. which would probably reduce the available area and thus array size. I wouldn't use a satellite flick for more than an estimate of max. avail. area, and then know/state that actual of both will probably be less.

[foo1bar]

Sometimes it is easy to see which is better from an aerial picture (the "satelite" pictures where you can see plumbing vents are actually from an airplane)

For example, if it would be possible to fit 1 row portrait, but not two rows landscape, probably portrait is better.
Or if you can see that it's likely you can fit a 3x3 grid in landscape, but only 1 row, 5 wide in portrait, you'd plan on landscape.

It really depends on how good the image is and what else is known about the site.

Maybe if you explain why you're asking you'll get more helpful advice...
Are you a homeowner that is looking at what layout for your house without having a site visit done?
Or an installer looking for how other people do it?

I'm guessing a homeowner.
As a homeowner, you can measure your roof yourself and figure out how you want the panels laid out.
Most solar installers will install modules that are ~39" x ~65" (1.00 meter x 1.64 meter)
So you can look at your roof and see how many you can fit on there with that dimension.
If you were in CA, I'd advise you to make sure you leave 3' space at the ridge - but I'm not sure if that's a rule in HI

[littleharbor]

If you were in CA, I'd advise you to make sure you leave 3' space at the ridge - but I'm not sure if that's a rule in HI
[/QUOTE]

3' at ridge AND gable ends.

[J.P.M.]

Adding to my 09/23 post @1923 hrs., if the aerial photo is truly overhead, the projected length of the roof along any non horizontal edge will look/scale/appear to be less than actual, roughly as the cosine of the degree to which it is non horizontal. For example, a flat roof at a 45 deg. angle to the horizontal will appear to be only about 70% or so as long (wide) as the actual length in that angled dimension due to the projection of that surface on to a horizontal plane.

Also, thinking about it, and not trying to separate fly crap from pepper too much, but are aerial views as usually available really "satellite" images from space as that term might imply, or aerial photos from planes ?

[ButchDeal]

Adding to my 09/23 post @1923 hrs., if the aerial photo is truly overhead, the projected length of the roof along any non horizontal edge will look/scale/appear to be less than actual, roughly as the cosine of the degree to which it is non horizontal. For example, a flat roof at a 45 deg. angle to the horizontal will appear to be only about 70% or so as long (wide) as the actual length in that angled dimension due to the projection of that surface on to a horizontal plane.

Also, thinking about it, and not trying to separate fly crap from pepper too much, but are aerial views as usually available really "satellite" images from space as that term might imply, or aerial photos from planes ?

We do all our plans with remote information, then correct with a site visit. If there are 3D ( tilted google earth or Bing photos that can be rotated for perspective) you can do very well remotely. We build a 3D model of the home though as well as trees and other shadow producing items. Perspective can really hose any measurements unless you are using some model generation software. Ours is also corrected via LiDAR and street view ( or customer ground based photos). We line up the 3D model to the same perspective as the different photos and adjust the model to match the view, then turn to another perspective and do the same. After two or three of these it should line up with all photos.
We have gotten pretty good about these remote models based on the actual measurements that come later with the exception of smaller obstructions. In some areas there is high resolution air plane photos were you can see vents etc, but in more rural areas you can't.
We give a little leeway to compensate and rarely have large adjustments after site visit
More often though we get adjustments due to a section of roof not being suitable or structural issues, and once the house was burned down and rebuilt but the google photos showed the old structure, Amazingly the homeowner never said anything about it till the site visit when the installer showed up to take actual measurements and check electrical. The installer was quite confused and thought we or he had the wrong house. We rearranged the layout and honored the original contract.

End result though you can make reasonable contract based drawings, we would never ship product and role installs based solely on them. Most areas you are going to need measurements and electrical info just for the permit anyway.

[ButchDeal]

Oh as I do a great deal of GIS work as well I can tell you that only the very highest ( lowest resolution) photos are from space. Both google, Apple, and Bing have extensive air plane photo recognize programs. Almost all are also now doing LiDAR.

[J.P.M.]

Butch: Thanx for the informed info. I kind of figured that projection and other issues had been addressed, but boots on the property is still common and sensible as you seem to confirm.

Regards,

[solarix]

We find that landscape orientation is rarely the way to go. (despite that some well known leasing companies do it regularly) Panels are almost twice as long as they are wide, so very few roofs can actually pack more panels one way than the other. Because almost all roofs are vertically framed on 24" centers, you'll want to run the solar rails horizontally across them and as a result portrait orientation use about half as much rails as if you go landscape. Of course, if you go with a railless system make sure you have all the locations planned out as if you have obstructions, they will drive you nuts figuring out where exactly the mounts need to go.

[Wy_White_Wolf]

If you know the slope of the roof you can use Google earth and sketch up to get an idea of what you can fit on the roof.

WWW