Old Satellite Imagery in Solar Design: New Roofs, Cut Trees and Moved Pins
A design in Cali-Graf — the free solar design app built by Cali Energy, a Los Angeles solar and roofing contractor — sits on Google's aerial photo and 3D height map of the home, and both are from one date — shown under the address and in the roof editor's top bar, for example Imagery Dec 2, 2023 · high quality. Anything that changed after that date isn't in the photo or the heights: a tree cut down still shades the roof in the calculation, a new addition has nothing to trace on, a new roof can throw off the measured pitch. Cali-Graf can't see those changes, so the designer adjusts for them — trace what is there now, set the pitch by hand, turn off shade analysis for a tree that's gone — and confirms the rest on site.
Check the image before tracing
When an address is found, the line under it shows the utility, the city and ZIP and the date of the aerial image. Two checks take seconds and save a wasted design:
- Is the pin on the right roof? An address picked from Cali-Graf's list in Los Angeles County comes with its exact point from the county's address records. An address found with Find is placed by Google, sometimes on the street or the lot rather than the roof — check that the customer's house is in the middle of the satellite view.
- How old and how sharp is the image? The roof you trace is the roof on that date. When the quality is medium or low, the label is marked as a warning: outlines and heights are less sharp, so the pitch of each face is worth checking.
The utility in the same line comes from the home's location; near the border between LADWP and SCE, compare it with the customer's bill. More on the address step in where a Cali-Graf proposal's numbers come from; doing both checks from the office before an appointment is covered in pre-qualifying a solar lead from the address.
What changed, and what to do
| What changed since the image | What Cali-Graf sees | What to do |
|---|---|---|
| The pin landed on a neighbor | The neighbor's roof in the middle | Trace the customer's roof on the same image, or find the address again |
| A tree was cut down | The tree, still shading the roof | Turn off Shade analysis — a standard 3% is taken instead |
| Part of the shade is gone | Shade that is partly out of date | Leave shade analysis on — it stays closer to the real loss |
| A new roof | The old roof surface; the heights may be off | Check the pitch of each face and set it by hand if needed |
| An addition or a new garage | Nothing to trace | Design the roof you can see; plan the new part on site |
| Panels already on the roof | The old system on the photo | Trace the faces under it; leave the part that stays empty |
The pin is on the wrong house
The aerial image in the roof editor covers an area about 70 m (230 ft) across around the pin, so the next-door houses are on it too. If the pin landed one house off, the customer's roof can simply be traced where it is. If the house is farther away, type the address again with the house number and ZIP, or pick it from the suggestions; once a roof has been drawn, Cali-Graf offers to start a new calculation for the other address rather than mixing two homes in one.
A tree that's gone
The shade comes from the heights on the image date, so a tree cut down since then still shades the roof in the calculation — and still darkens that part of the sun map. If the tree is gone, or will be before installation, turn off Shade analysis under Price & settings and calculate again: the real shade is ignored and a standard 3% is taken off instead.
If only some of the shade is gone — one tree of several, a tree trimmed rather than removed — leave shade analysis on. On a shaded roof, the flat 3% is far less than the real loss, and production and savings would come out higher than the home will see. How the shade is worked out for every panel is in designing a solar layout on satellite imagery; a tree over the roof can also disturb the measured pitch of the face under it.
A new roof
A re-roof after the image date usually keeps the roof's shape, so the trace still fits, but the photo shows the old surface, and a change to the structure — or a tree that hung over the roof when Google measured it — can confuse the heights. Faces where that happens show Google heights are uneven on this face — check the pitch and pick it if it looks wrong. Check the pitch on site and set it by hand; see what to trust in a remote solar layout. Planning a new roof and solar together is covered in a new roof and solar at the same time.
An addition or a new garage
A part of the house that isn't on the photo has nothing to trace on, so panels can't be placed on it in Cali-Graf. Design the roof you can see and plan the new part on site. A garage or ADU that is on the photo is traced like the house and joins the same system; see solar on a detached garage or ADU.
Panels already on the roof
If the photo shows an old solar system, trace the roof faces under it as usual and ask the customer which panels stay; leave that part of the roof empty. Keep in mind that the calculation assumes the home has no existing system — adding panels to solar that stays in place isn't something Cali-Graf calculates yet, and a Green Button file from a meter that already has solar isn't accepted. The full list is in What Cali-Graf doesn't do yet.
No data at all
Two messages mean Google's data is missing rather than old:
- Google has no roof data for this address, so the roof editor can't open it — Google doesn't have 3D roof data for the home yet, which happens with new construction and some rural areas. The roof can't be designed in Cali-Graf for now.
- Google has no roof or shade data for this house — there are no heights to work out the shade. Turn off Shade analysis and calculate again; a standard 3% is taken for shade instead.
Undoing a change that went wrong
Adjusting a design for an old image sometimes takes a few tries. Every change can be undone, and History in the editor's top bar lists the saved versions of the design (Saved · v3), so an earlier layout is never lost. To keep two versions side by side — with and without a tree, say — copy the calculation; the copy takes the roof with it.
Open a home where something changed recently — a tree, a new roof — and see how the design handles it.
When the site visit decides
Cali-Graf's design is an estimate from public data and doesn't replace a site visit. Some signs say the visit matters more than usual:
- the image date is older than work the customer mentions — a new roof, an addition, panels, trees removed;
- the image quality label is medium or low;
- a face shows Google heights are uneven on this face;
- trees hang over the roof, or used to;
- the pin had to be moved, or the home sits near the LADWP–SCE border.
Frequently asked
How do I know how old the satellite image is?
A tree was removed. Will the estimate still show its shade?
What if the address pin lands on the neighbor's house?
Can I put panels on an addition that isn't in the image?
What if the roof already has solar panels?
Why can't Cali-Graf open the roof editor for some homes?
Related reading
Sources & methodology
Product facts on this page come from Cali-Graf's own help center and the pages linked below; figures in examples come from the stated inputs. Features, limits and supported utilities change; each was verified October 16, 2026.
- Cali-Graf Help — Old imagery, a new roof or trees that are gone
- Cali-Graf Help — Make sure the right house is found
- Cali-Graf Help — Find the house
- Cali-Graf Help — Aerial image and height data
- Cali-Graf Help — Turn shade analysis on or off
- Cali-Graf Help — How your work is saved
- Cali-Graf Help — What Cali-Graf doesn't do yet
- Cali-Graf — Terms of Service
- Google — Solar API overview
Check the image date before the next design
Cali-Graf shows the image date and quality above every roof, measures pitch from Google's heights and lets you adjust shade and pitch when the photo is out of date. Free, with daily fair-use limits; the Fix a problem section of its help center has each step.
Prepared by Cali Energy, October 16, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)