Weekly change flags for one named site.
New structures, excavation and hardening on your site, marked on a dated map each week.
Spec
- GSD
- ≤0.5 m VHR
- Cadence
- Weekly
- Platform
- VHR satellite / aerial
- Spectral
- RGB
- Delivery unit
- One named site or perimeter
- Formats
- GeoPackage, KML, PDF map, CSV log
The files, and what is in them
| Deliverable | Format | What's in it | Cadence |
|---|---|---|---|
| Weekly change map | PDF map + GeoPackage layer | The site plan for that week with every flagged change marked and numbered. Each mark carries the date of the pass it was seen in. Lands the same week, ready to drop into your site note or open in ArcGIS Pro or QGIS. | Weekly |
| New structure footprints | GeoPackage polygons | An outline for each new structure, with its area in square metres and the first pass it appeared in. Where a structure is still going up, the outline is redrawn from the next pass, and the earlier one stays in the record. | Weekly |
| Excavation volume estimate | CSV + polygon layer | A cut-area polygon and an imagery-derived volume estimate in cubic metres for each excavation. It is a read from imagery, not a survey figure, and the log says which passes it was worked from. Use it for the question of how much ground has moved. | Weekly |
| Hardening flags | GeoPackage points and polygons | Berms, earth cover and reinforced structures marked where they show at the surface, each with a note on what was seen. A flag cues a closer look. It says nothing about intent. | Weekly |
| Change log | CSV | One line per flagged change: id, type, date first seen, latest pass, area, and a free-text note. Sorted by first-seen date so a tempo reads straight off the column. | Weekly |
How it works
Supply the site
A site name and a perimeter polygon (
shapefile,GeoPackageorKML), or a site plan we can draw the perimeter from. Add your baseline date if you have one.Baseline
We set the reference from the imagery archive for the site, and tell you which date it is before the first weekly run.
Weekly pass
Each week the newest usable VHR collect over the perimeter is compared with the baseline and the previous pass. Change detection and imagery-derived 3D read flag new construction, excavation and hardening.
Delivery
The change map, layers and log go to you, and every flag stays in the record for the next week's comparison.
Limits
| Condition | Effect on the output | In the delivery |
|---|---|---|
| Weekly needs a usable pass | Cloud cover, haze or an off-angle collect can leave a week without a clean image. | A change seen then is flagged in the next cycle, and the log shows the gap. |
| 0.5 m is the floor | A structure a few metres across resolves as a small object. Thin walls, fences and fine surface texture are narrower than a pixel and are not traced. | Hardening is flagged where it shows as a berm, earth cover or a structure with area, not as a thin line feature. |
| Excavation volume is an estimate | Volume comes from imagery-derived 3D and stands or falls with the pass geometry. | It is not a surveyed figure and carries no accuracy claim. |
| Surface only | Optical imagery sees the surface. | Underground work, tunnel portals under cover, and anything under canopy or a roof are not visible until something shows outside. |
| Flags are cues | A flag marks a new roof, cut or berm at a place on the ground. | Whether it matches a declaration, or breaks a treaty, is an analyst's call and a legal one. |
| RGB only | No thermal, radar or multispectral layers. | Activity that only shows in those bands is not in this product. |
Why this exists
Every week you pull the newest collects over the site, line them against your baseline and flip between dates looking for new roofs, spoil piles and berms. Each find gets a marked-up image and a line in the log. It is careful work and it repeats for every site on the list. It also gets done twice in the weeks the archive hands back a cloudy or off-angle pass. Facility Expansion does the first comparison for you and hands you the flagged changes to check, so your time goes to what they mean.
Who it's for
Who it's for
- Imagery analysts and compliance teams who keep a weekly watch on a named strategic site.
- Teams that compare a site against a declared plan and need a dated map of what has changed.
- Analysts who want a first pass done before they decide where to task a closer look.
Who it's not for
- Teams looking for a legal or treaty determination. That stays with the analyst and the legal office.
- Underground, covered or interior activity. Optical imagery cannot see it.
- Wide-area searches for unknown sites. This watches a site you name.
- Live monitoring. Cadence is weekly, and a cloudy week can push a flag back.
Questions from evaluators
Is weekly truly every week?
The target is one usable pass per week. Cloud or a poor collect can push a flag to the next cycle, and the log shows which weeks had a pass.
Does a flag prove non-compliance?
No. It marks change for analyst review. Any determination stays with you.
How is excavation volume estimated?
From imagery-derived 3D over the perimeter. Treat it as an estimate for sizing the work. A survey would give the figure to sign off on.
How do we check it against our own work?
Every flag carries its pass date, so you can open the same image in your own GIS and check the mark. Run it beside your manual comparison for a few weeks before you lean on it.
Can it watch more than one site?
Yes. Each site is tracked and mapped on its own, with its own baseline and log.
What if the site is underground or covered?
Optical imagery only sees the surface. Anything below ground or under cover is out of view.
What do we get, and in which formats?
A map, vector layers and a change log that open in ArcGIS Pro or QGIS. The spec table lists the formats.
Who owns the imagery and the layers?
Terms for the delivered layers are set in the contract before work starts. The imagery sources carry their own licences, which are stated in scope.
How is it priced?
Each site is scoped and quoted on its own. You get a written scope you can take through procurement.
Name the site and the perimeter.
We will tell you which baseline date we would start from.