Satellite vs Aerial Imagery for Asset Detection (2026)

Take a rooftop unit with an assumed 1.8 by 2.4 meter footprint. In a 7.5 cm aerial image, its top spans roughly 24 by 32 pixels. In a 30 cm satellite image, it spans 6 by 8. That gives the finer image 16 times as many grid cells over the same footprint, before considering blur or viewing angle.

Those pixels affect the next sales decision. You might need to distinguish separate units on a warehouse roof, establish whether equipment was added, or decide which building deserves an HVAC survey. This comparison focuses on optical imagery used to inspect visible assets. The sharper picture and the newer picture can answer different parts of that question. Buying either one without checking the other leaves work for the estimator.

Asset Search by PorchRocket cross-references aerial and satellite imagery with property records and public datasets, then has people review the candidates. The deliverable connects the visible asset to its location and ownership, with a decision about fit. Here is how I would choose the evidence behind that decision.

How we compared imagery for asset detection

For a trade company, the best approach resolves the target, supplies a relevant capture date and delivers a reviewed record the sales team can act on.

I would compare four things before buying access:

• Source detail relative to the smallest asset that changes your decision.
• Capture dates and coverage across the territory you intend to work.
• Alternate views that help settle ambiguous equipment or site layouts.
• Total effort per accepted site, including ownership research and review.

Approach	Best fit for a buyer	What the buyer still handles
Asset Search	Finished investigations for trade companies, service networks and asset programs	Set the acceptance rules with our team and act on the reviewed findings
Detailed aerial imagery	Examining small visible equipment and site arrangements	Search the territory, interpret candidates and join records
High-resolution satellite imagery	Repeat observations over a broad territory	Verify resolution, usable capture dates and the identity of changes
Open public satellite datasets	Regional land-cover context and broad change screening	Build the analysis and obtain finer evidence for small equipment

The comparison is about the work returned. A map layer and a reviewed equipment inventory have different finishing costs, because somebody must locate the asset and resolve doubtful cases before joining the ownership information that lets a rep start working the account.

Price that finishing work. Before buying imagery for several counties, I would ask the sales manager to open one proposed record and explain how the rep will decide whom to call, what service to discuss and which question still requires a visit.

The broader asset inventory from aerial imagery guide explains how to scope that finished inventory. For a campaign built around commercial buildings, aerial imagery lead generation connects the evidence to account selection and outreach.

Resolution from 7.5 cm to 30 meters

A 7.5 cm sampling grid gives the example rooftop unit 768 footprint cells, compared with 48 at 30 cm and 12 at 60 cm.

Ground sample distance, or GSD, describes spacing between pixel centers on the ground. The federal digital orthoimagery standard defines that spacing and distinguishes source sampling from published image pixels. Divide an object’s dimension by GSD to estimate how many pixels span it.

For the opening unit, the arithmetic is 1.8 / 0.075 = 24 pixels across and 2.4 / 0.075 = 32 along. Multiply those dimensions for 768 cells. At 30 cm, the same calculation gives 6 x 8 = 48.

Sampling grid	Cells across the assumed 1.8 m width	Cells along the assumed 2.4 m length	Footprint cells
7.5 cm	24	32	768
15 cm	12	16	192
30 cm	6	8	48
60 cm	3	4	12

These are geometric comparisons, with the footprint aligned to the grid. Finer sampling gives the reviewer more cells across the equipment. Identification still requires enough detail to distinguish the target from adjoining roof features and apply the buyer’s equipment definition.

Define the counting unit first. If the service manager counts an attached assembly as one unit but the researcher counts each visible box separately, buying a finer image will not resolve the disagreement about which buildings meet a five-unit rule.

The resolutions have documented examples. MassGIS’s 2025 aerial acquisition provides 7.5 cm imagery for Cape Cod and 15 cm elsewhere in Massachusetts. ESA’s earth observation guide describes the 30 cm satellite class. Those are comparison cases, rather than universal specifications for either platform.

Public satellite datasets operate at another scale. Sentinel-2 has four bands at 10 m. NASA lists Landsat 9 with 30 m visible and shortwave-infrared sampling and a 15 m panchromatic band. A 1.8 m cabinet occupies less than one pixel across in those grids. Use broader observations to screen areas, then obtain finer evidence for equipment identification.

Check the native sampling. USGS explains that enlargement adds no recorded detail. Its JACIE evaluation guidance also treats spatial image quality as more than pixel spacing. A bigger screenshot cannot settle a feature absent from the source observation.

How often is satellite imagery updated?

Landsat 8 and 9 offer an eight-day combined acquisition opportunity, while Sentinel-2 has a five-day design revisit at the equator.

Those published intervals describe particular missions. They are not schedules for every satellite image available over your warehouse. USGS documents the offset 16-day Landsat cycles; the Copernicus mission page states Sentinel-2’s design interval. Neither figure describes a 7.5 cm aerial service or promises a new 30 cm image of your address.

Separate the clocks. A revisit is an opportunity to observe. Acquisition is the capture that occurred. Publication is when the processed image became available. Your decision depends on the latest capture in which the target can be evaluated.

Natural Resources Canada’s temporal-resolution guidance explains how clouds and changing observation conditions affect repeat coverage. A cloudy pass does not refresh the evidence for equipment hidden beneath it. Check visibility at the asset, even when the wider image looks acceptable.

Aerial collection follows the project. The USDA NAIP description specifies leaf-on photography during the growing season. Its repeat flying cycle is no more than three years, generally every other year for most states, with documented 0.6 m and 0.3 m products that require the buyer to check the particular coverage being considered.

MassGIS offers a clear date example: its spring 2025 collection was delivered in late 2025 and early 2026. Calling that a 2026 photograph would change the apparent age of every asset in it.

For a rooftop service campaign, I would require a capture date on the reviewed record and flag sites whose evidence falls outside the campaign’s age limit. For a new-installation watch, I would require both the last adequate view without the installation and the first adequate view showing it. That interval is what the images establish.

Keep old evidence in its place. A detailed older image can support an equipment interpretation while a newer view supports continued presence, but I would require the reviewer to identify which date supports each claim before describing the installation as current.

What do oblique images add?

A side-looking view can supply shape and site context that a straight-down image does not show, helping reviewers investigate ambiguous rooftop and yard assets.

Nadir means looking straight down. Oblique photography looks from an angle. Natural Resources Canada distinguishes vertical and oblique photographs and explains why changing scale across an oblique image complicates measurement. I would request alternate directions when a single perspective leaves the target uncertain.

For rooftop equipment, the alternate view might help separate a raised cabinet from a flat roof feature, while another direction at a loading area might expose the building face associated with the dock arrangement that the buyer wants to investigate.

Treat those as questions to test against the available views. A side image of the wrong wall settles nothing.

Satellite viewing angle matters too. ESA describes off-nadir viewing and building lean: elevated objects can appear displaced from their ground position, especially at larger viewing angles. Two pictures taken from different directions can therefore make the same rooftop object appear to move against the surrounding map.

Use a suitable orthoimage for the location work. USGS defines an orthoimage as imagery corrected for terrain and camera-tilt distortions, giving it a uniform map scale. Ask for the mapping accuracy relevant to your task, especially when the equipment sits near a parcel boundary and the record must establish which property should receive the observation; pixel size alone does not establish that alignment.

I would keep the overhead location and the supporting side views attached to one site ID. Record which view supports which observation. If the question is whether a cabinet exists, preserve the image that shows it. If the question is where it sits, preserve the mapping evidence used for that position.

What does aerial or satellite imagery cost in 2026?

Public Landsat and Sentinel-2 data are free to access, while commercial imagery and finished investigations require a scope that accounts for coverage and delivery.

USGS confirms no-cost Landsat downloads, and Copernicus provides Sentinel-2 data free of charge. Free aerial imagery is available too: MassGIS permits public use and distribution of its 2025 imagery. Check that public coverage against your territory and capture-date requirements before buying an image layer. Equipment interpretation and ownership research still require work after the data arrive.

For purchased imagery, compare archive coverage with a new acquisition. ESA’s pricing guidance identifies resolution and scene area among the cost factors, along with archive versus new capture. I would request an itemized scope rather than budget from an unsourced price per square kilometer.

Ask what you can retain and share with the field team. Establish whether the order includes capture metadata and the evidence used to resolve each candidate, with a territory boundary clear enough that the sales manager can distinguish searched sites from areas the order has not investigated.

Request refresh terms separately. A recurring review has a different workload from one image purchase.

Available Asset Search terms include per completed investigation or per accepted result, plus subscriptions and success-based arrangements tied to an agreed outcome where appropriate. For this equipment campaign, I would start per completed investigation: the buyer needs an answer for each candidate, including rejections. A small paid pilot is credited toward the full order. The quote follows the agreed rules and territory.

When Ground Control is the faster purchase

The fastest way to get a standard rooftop-HVAC target list is Ground Control by PorchRocket. Choose the area, business type and building size, then filter for HVAC present, 2+ or 5+ visible rooftop units. Commercial buildings cost $10 to $20 each, with orders starting at 10. Files arrive within 48 hours after payment, with why each building matched. Wrong matches receive credit within 30 days. Owner information and decision-maker research are add-ons. Use the rooftop HVAC building list or start in Ground Control when those filters cover the campaign.

For the public side of an HVAC territory, Bid Control by PorchRocket finds city, county and school jobs for your trade and area, with bid papers and addenda in one place. Use it to follow advertised work while the property list directs outreach to buildings that fit your service department.

Which assets can each image type find?

Detailed aerial views favor small equipment review, while repeated satellite observations can help screen larger sites and flag changes for closer investigation.

Start with the question a buyer needs answered. A service department looking for buildings with several rooftop units needs different evidence from a manufacturer mapping large outdoor installations. Neither buyer should approve a search based only on a picture of a solar farm that looks sharp at regional scale.

The following table is how I would assign the investigation. Test the proposed imagery on examples from your territory before approving the wider search.

Target and buyer	First evidence I would examine	Additional evidence to request	Decision the record feeds
Rooftop units for an HVAC service department	Detailed overhead equipment layout	Another angle and a newer capture where available	Whether to approach the building for a service survey
Outdoor tanks for a service network	Visible vessels and their arrangement	Site context, parcel and relevant public records	Whether the installation fits the service territory and application
Loading docks for a door-service company	Building face and loading configuration	Obliques and owner or manager research	Which facilities deserve an introduction
Solar sites for maintenance sales	Site extent and array pattern	Finer views and a dated comparison	Which installations warrant qualification
Ponds for a maintenance contractor	Basin form and surrounding drainage context	Alternate dates and recorded facility information	Which sites need a maintenance-responsibility check
Industrial yards for a supplier	Yard layout and access context	Recent views and property records	Which sites fit the account profile

These assignments follow an interpretation method, rather than a universal pixel cutoff. Natural Resources Canada’s air-photo guidance describes combining shape with pattern and surrounding context, using shadows as another clue. A rectangle alone is a weak equipment definition. Record the observations that distinguish it from the nearest lookalike.

For standard prospects, use the parking-area list or loading-dock building list. Custom combinations belong in Asset Search. For an equipment maker defining a serviceable population, installed base mapping explains how to connect each equipment record to its site and buying account.

Cross-reference views before joining property records

Asset Search links observations from different images to the same site, then joins property records and owner information to support a reviewed fit decision.

Begin with a stable site ID. An equipment observation should point to the location where it was seen, with the capture date and view attached. Keep a count of objects separate from a count of buildings. Four cabinets on one roof do not automatically mean four buying accounts.

Next, compare the views. Does the more recent image show the same roof arrangement? Does another angle explain a shape that looked like equipment overhead? If the evidence disagrees, keep the disagreement in the investigation instead of choosing the image that produces the larger prospect count.

Then join the parcel and ownership. I would retain the parcel identifier and the ownership record’s date, with a note explaining how the observed asset relates to that parcel. Ask the reviewer to flag equipment near a boundary for confirmation. A nearby mailing address should not decide which owner receives a service proposal.

Use records to answer questions the image cannot settle. For a roof-age campaign, the roof age data guide explains the record-research side. For an equipment campaign, ask the owner for the equipment schedule and confirm technical details during an authorized survey. A photograph establishes observations available in that view.

The handoff should make the next action obvious. Give each site a stable ID with coordinates and a parcel reference. Attach the observations and their dated evidence, then the disposition with its follow-up. Include owner information and decision-maker contact where applicable. For an unresolved site, specify the one field check needed to settle the question.

Keep conflicting records visible. If an ownership record and the person answering the building’s phone point to different organizations, I would have the rep establish who manages maintenance before sending the proposal, while retaining the parcel’s recorded owner in its own field.

An example call opener: “We are reviewing service coverage for buildings with several rooftop units in this industrial park. Who handles your HVAC maintenance?” It connects the observation to a service question without claiming an equipment problem.

Accuracy means reviewing misses as well as matches

A credible inventory explains which sites fit, which were rejected and which remain unresolved, rather than reporting only a large count of apparent matches.

Set the acceptance rule before reviewing the pilot. For an HVAC campaign, decide whether the buying unit is a building with any visible rooftop HVAC or one with at least five qualifying units. Define how the team handles attached buildings and partly obscured roofs. Put difficult examples in the rules.

I would inspect accepted sites and a sample of rejected candidates. Accepted records show whether the returned prospects meet the definition. Rejected examples let your expert challenge exclusions. If the reviewer has misclassified a qualifying configuration, correct the rule before revisiting the affected records.

Keep an unresolved category. It preserves a candidate whose available evidence cannot answer a required question. That category needs an action, such as confirming the roof arrangement during an authorized survey, rather than a vague request for more research.

Ask for the search boundary too. An inventory of a defined industrial corridor supports a corridor count. It does not establish how many installations exist across the county beyond that boundary. Keep uncovered areas visible in the project handoff.

Our recall-first search goes beyond directories and existing databases. People review every candidate before delivery. Every disposition comes back, so your expert can audit the reasons and adjust the search definition instead of trying to infer the method from a spreadsheet containing hits alone.

Refresh the inventory when the buying decision changes

Match the review schedule to the decision: quarterly territory planning, monthly campaign updates or a faster change watch require different evidence and delivery arrangements.

A refresh can mean two separate jobs. One checks new imagery for physical changes. The other reconsiders existing sites after your requirements change. Asset Search supports both. A new repair method can make a previously excluded installation eligible without any equipment moving.

Buying decision	Cadence I would request	What the update should contain
Annual territory and staffing plan	Annual baseline review	Current dispositions and coverage gaps
Dealer territory book	Quarterly editions	New, removed or newly eligible installations
Active service campaign	Monthly review	Changed sites and the next qualification action
Time-sensitive installation watch	Weekly review, or near-real-time alerts where daily satellite coverage exists	Before-and-after capture dates and a reviewed change

These are buying schedules. Confirm which usable observations can support them in the selected territory. A weekly delivery can report no verified change; it should not relabel the same old image as a new observation.

For each changed record, I would retain the previous disposition and the reason it changed. Label a newly visible installation separately from a revised eligibility decision. Corrected interpretations need their own label. Sales needs to know why a site entered the queue this week.

Avoid duplicate assignments. When a refreshed site already belongs to an active account, I would send the changed equipment observation to that account’s rep rather than create a second prospect and have another salesperson ask the same property manager for an introduction.

The new-installation change-detection guide covers that comparison process. Use asset monitoring when the requirement is to keep watching the territory after the initial inventory, with subscription delivery and agreed change rules.

The money on 180 reviewed HVAC sites

In this planning model, reducing research from 54 hours to 12 frees 42 hours and more than triples owner-outreach capacity within a 72-hour labor budget.

A commercial HVAC service department in Fort Worth wants 180 buildings that fit its crew and territory. Assume both approaches investigate 540 candidate addresses and identify the same 180 qualifying buildings, each with a different buying account. Manual screening takes six minutes per candidate, including record reconciliation. Budget internal labor at $47 an hour.

The reviewed inventory returns all 540 dispositions. Assume the buyer checks each of the 180 fits for three minutes and audits a sample of 45 of the other 360 records for four minutes each. Manual investigation takes 540 x 6 / 60 = 54 hours. Buyer review takes (180 x 3 + 45 x 4) / 60 = 12 hours. The difference is 42 hours, representing 42 x $47 = $1,974 of internal time available for other work. If the audit exposes a classification error, budget for checking the affected records before outreach.

Now hold the research-and-outreach labor allocation at 72 hours. Assume each owner’s outreach work, including preparation and follow-up, consumes 30 minutes. The scoped research quote and later survey, travel and proposal costs sit outside this labor budget and enter the acquisition-cost calculation below.

Internal workload	Manual address screening	Reviewed site inventory
Research and file-check hours	54	12
Hours left for owner outreach	18	60
Owners worked at 30 minutes each	36	120
Total internal labor, 72 x $47	$3,384	$3,384

That is 120 / 36 = 10/3, or about 3.33 times the outreach capacity. The same team has more time to qualify buyers before sending a truck. The $1,974 stays in payroll and funds that extra outreach; it is not a second cash saving.

For account value, assume an annual PM agreement produces $6,750 in revenue at a 42% gross margin, and the account buys six paid years. Annual gross profit is $6,750 x 0.42 = $2,835. Customer lifetime value, using undiscounted gross profit, is $2,835 x 6 = $17,010. Use the customer lifetime value calculator to replace those inputs with your agreement economics.

Work the base funnel from those 120 accounts receiving outreach. Budget for 30 conversations leading to nine authorized surveys, then two signed agreements. Those assumptions mean 30 / 120 = 25% reach a conversation, 9 / 30 = 30% of conversations produce a survey and 2 / 9, about 22.22%, of surveys produce an account. The inventory conversion percentages below are rounded to two decimal places.

Signed accounts from 180 sites	Share of inventory won	Six-year account gross profit
Low: 1	0.56%	$17,010
Base: 2	1.11%	$34,020
High: 3	1.67%	$51,030

Customer acquisition cost is total acquisition spend divided by signed accounts. Here, add the scoped research quote to $3,384 of internal labor and the survey, travel and proposal budget. Divide that sum by one, two or three accounts for the low, base and high cases. Keep those additional costs in the calculation when comparing options.

My decision rule is to require the low case’s $17,010 in six-year gross profit to exceed that total spend. Then check cash payback: the assumed agreement generates $2,835 / 12 = $236.25 in monthly gross profit, so divide acquisition cost per account by $236.25 to estimate payback months. This assumes even monthly gross profit across six paid years, with no discounting or growth. Set the maximum acceptable payback before ordering the search.

Check the route first. Put the prospective buildings beside existing service stops before assigning surveys, so the estimator can reject a distant account whose travel would consume the margin even though its rooftop configuration meets every equipment rule in the research order. Track accepted sites and signed agreements so the next order uses your own conversion rates.

When another tool is the better buy

Use a narrower method when the decision needs regional context, one authorized site inspection or analysis your existing mapping team can already deliver.

• For broad vegetation or land-cover screening, free public satellite data may provide the scale you need. Begin with the mission specifications and test the analysis against the question.
• For one known building needing a current equipment schedule, ask the owner for records and arrange an authorized survey. A territory-wide search adds little to that job.
• For a mapping department with suitable licensed imagery and staff assigned to interpretation, work through the existing archive first. Compare its finishing effort with a reviewed investigation before purchasing another layer.

I would choose Asset Search when the job is finding assets across a territory and delivering evidence connected to owners. I would choose Ground Control when standard building filters define the prospects. Decide which record the rep or field manager needs, then buy the shortest route to that record.

How to choose imagery for asset detection, step by step

Run a small pilot against written acceptance rules, then expand only after your expert can use the returned evidence to make the intended decision.

1. Write the buying decision. For the HVAC campaign, specify buildings inside the service territory that qualify for an equipment survey. State the minimum visible configuration and the building types your crew serves.
2. Mark the territory boundary and exceptions. Separate a first industrial corridor from a later county expansion. Supply known sites as test cases, including examples that should be excluded.
3. Request an Asset Search pilot through the asset search form. Give the target, territory and edge cases. Ask for dated aerial and satellite evidence cross-referenced with records, human review and every disposition, delivered in the team’s chosen format.
4. Check the evidence requirements. Compare target dimensions with source GSD, confirm capture dates and examine alternate angles where needed. Decide which observations must be current before approving a site.
5. Review fits and rejected examples with the person who knows the equipment. Resolve disagreements in the definition. Give every unresolved record one next check and assign responsibility for doing it.
6. Test the handoff. Load the pilot into the CRM, dealer system or GIS workflow you intend to use. Confirm that site IDs, ownership and evidence remain connected and that the sales manager can assign the next action.
7. Work the first outreach batch and record its funnel. Count conversations and authorized surveys, then signed accounts and gross profit. Use those results to compare the research spend with account value.
8. Expand and set the refresh schedule. Request the next territory only after the pilot meets the agreed acceptance rules. Choose quarterly planning editions or a faster installation watch according to the decision and available coverage.

Keep one person responsible for acceptance. Have the estimator check equipment interpretation and the sales manager check whether the record supports an introduction. Settle both questions during the pilot, then use the agreed rules for the larger order.

Building a reviewed territory with Asset Search

Asset Search combines imagery, records and human review to return an asset inventory your team can qualify, assign and refresh across the contiguous United States.

Start with the asset and the decision it feeds. Our team sets the search rules with your experts before investigating candidates. The evidence comes back with each disposition. For this rooftop-equipment campaign, the order should specify these six deliverables:

• A defined search area and equipment acceptance rules, including the edge cases that matter to the service department.
• Locations and parcels connected to the observed rooftop configurations, with dated views supporting each finding.
• Owner information and decision-maker contact where applicable, attached to the same site record used by sales.
• Fits, rejects with reasons and unresolved sites with the one field check that settles the question. Every disposition is returned.
• CSV, Excel, GIS-ready files or an import for the CRM or dealer system that will receive the territory.
• An agreed refresh arrangement for new imagery, revised service rules and territory changes, with before-and-after dates for monitored changes.

Per-investigation terms fit the initial audit because every candidate needs a disposition. Per-accepted-result terms fit a campaign buying qualifying finds. A subscription fits continuing monitoring. Begin with a small paid pilot credited toward the full order, then expand from the reviewed result.

Tell us what to find and where in the two-minute form. Asset Search returns the investigated territory so your next selling hour goes to a building your crew has a reason to pursue.