Your Pin Is Older Than the Field: Check Two Image Dates
Last season's pin is a memory with coordinates, and the ground under it has had a year to change. Two dated images of the same spot can show whether visible objects changed between flights, though neither can show that a deer uses the place. This guide covers how to get a second date, what to look for, where a satellite crop layer fits, and an eight-line worksheet to fill before you hunt an old pin.
ITwo dates
The National Agriculture Imagery Program (NAIP) is the public leaf-on aerial program, and USGS describes a refresh of every three years or less for 2009 to the present. A pin dropped on a 2022 tile and hunted in 2026 can sit on a woodlot that has since been cut, a grass field that has been burned or a pond that has silted in. FDR's leaf-off imagery guide covers how to find out how old your app's imagery is. This guide starts one step later, when you know the date and need a second one.
The change that rewrites a pin may not be on your ground at all. Purdue's guide to assessing land for wildlife says a plan has to weigh habitats and natural features on surrounding properties, and it uses deer as an example of an animal that uses one property for only part of its needs. A cut next door or a new plot across the fence can change what your own acreage is worth as a pin while your trees stay exactly where they were.
IIGetting a second date
USGS says EarthExplorer can search, preview and download NAIP, and it points to the program's customer service office for imagery that has been acquired but is not yet in EarthExplorer. That gives you a way to look at the same ground in more than one year.
NAIP is flown leaf-on, so two NAIP flights compare like with like. A leaf-on flight set beside a winter image compares two seasons, and much of what differs is the season itself: leaves and field cover. When the seasons differ, read only the objects that do not follow the calendar, such as roofs, lanes, cut boundaries and skid trails.
IIIWhat two dates show
Compare the older image with the newest one you can get. You are looking for change in objects, and this table lists the changes worth catching.
| Change you can see | What it might mean | What you still verify | What it does not mean |
|---|---|---|---|
| Canopy holes, skid trails, log decks | Timber harvest or storm damage | How old the cut is; slash or clean floor | That deer left the area |
| A rectangle of different color in timber or grass | New plot, disking or construction | Planted or fallow; who owns it | That the plot gets daylight use |
| Field pattern, pivot tracks or residue | Crop rotation or tillage | This year's crop and harvest state | A travel route |
| A basin that used to look dark, now bare or overgrown | Dry pond or drained wetland | Water this week | That deer no longer drink on the farm |
| New roof, lane or lot | The human edge moved | When people are there | Pressure everywhere |
| Linear cover gone or gapped | Fence row pushed out or ditch sprayed | Whether your travel hypothesis died | That deer have nowhere to go |
If nothing changed between the photos, you have not confirmed use. You have only failed to disprove the old map.
A cut is also a process. Purdue notes that regeneration from a timber harvest may take 15 to 50 years or longer to reach its desired condition, so the second image catches one frame of a change that keeps going.
IVCrop layer
The USDA's National Agricultural Statistics Service (NASS) publishes the Cropland Data Layer (CDL). Its FAQ describes an annual, crop-specific raster built from satellite imagery and agricultural ground reference data, at 30 meters for 2008 through 2023 and 10 meters beginning in 2024. Each year's layer arrives the following winter, and NASS lists the 2025 layer as released February 27, 2026. Open the newest layer in fall 2026 and it describes the 2025 crop.
- NASS states that no farmer-reported data can be derived from the layer, so it is a satellite classification and not a planting record.
- Counting pixels and multiplying by pixel area gives biased area estimates, typically low, and NASS calls those figures raw numbers needing bias correction. Do not turn a pixel count into your acreage.
- NASS handles field edges separately. It buffered its training fields inward by 30 meters for the 2007 to 2018 layers and by 15 meters starting with the 2019 layers, because the buffering "removes spectrally mixed field edge pixels" from the classifier. A fencerow, ditch or grassed waterway sits on exactly that edge.
- A 30-meter pixel is roughly 100 feet across, wider than many ditches and fence rows.
Treat a year-to-year class change as a reason to go look, not as a record of what grew in a field. For anything about crop or harvest timing, stay at the county level. FDR's standing corn guide covers the county harvest read, and this guide sticks to the slower question of whether the object you pinned still exists.
VPin-age worksheet
If a line stays blank, the pin is still a hypothesis.
- Pin date. When you dropped it, and the image year under it if you know it.
- Image dates. The flight year and season of the older and newer images. If you cannot name a year for either, stop and find one.
- Object then. One sentence naming what the pin was about, such as a cedar point on the west ditch.
- Object now. The same sentence written from the newer image. If you cannot write it, you are guessing.
- Crop layer, optional. The class last year and this year, read as a prompt to look.
- Human edge. Any new house, lane, camera or cattle.
- Evidence in hand. What you found on the ground, as opposed to on a map. If the honest answer is that the map looked good, you hold no evidence of deer.
- Walk plan. One edge, one wind, one hour, on ground you own or have permission to enter.
Suppose your pin sits on a weedy corner between beans and a woodlot. The older image shows the corner, and the newer leaf-on flight shows a rectangle of bare dirt and a new lane off the county road. The corner is no longer the corner. Retire the old pin until a walk on owned or permitted ground says otherwise. It may turn into a plot that pays off in October, or it may be a building pad, and the second image is what forced the question.
VINext step
Pick one pin you trust from last season, name the image year under it, and pull a second flight. Fill the worksheet, then walk one edge. If the pin sits on private ground, remember that an owner name in an app is a county record as of a date and a parcel line is not a survey. FDR's landowner name check walks through verifying the owner of record before a permission ask, and a map account never stands in for permission.
To see how one layer states its age, see what Scout maps. Its features page gives a flight year for its leaf-off imagery, flown in winter 2025.
- Aerial imagery, terrain, and parcel layers describe the ground on the date they were captured or recorded. They are not surveys or legal boundaries.
- Nothing here guarantees deer activity or hunting success. Confirm seasons, regulations, and permission before you hunt.
Fully Drawn Research is an independent data analysis desk, not affiliated with the Illinois Department of Natural Resources, the Illinois Department of Transportation, or any mapping or outfitting provider. FDR maps give context from public imagery, terrain, and parcel records; they do not predict deer activity or replace a field check.