Mastering GPS Accuracy for Your Photos

While modern GPS technology is remarkably accurate, recording a precise location on your device isn't always straightforward. Your phone or tablet doesn't rely on satellites alone. Most devices combine information from GPS satellites, mobile networks, nearby Wi-Fi signals, and onboard sensors to estimate your position as accurately as possible.

The Secret to Better Photo Locations

If you pull your phone out of your pocket and snap a picture immediately, the GPS location saved in the image file may not be as accurate as it could be. This happens because your device hasn't had enough time to communicate with satellites and other positioning systems to determine its exact coordinates.

Environmental factors such as heavy cloud cover, dense tree canopies, steep valleys, and poor visibility of the sky can also reduce accuracy. Clear skies generally provide the best GPS performance and often the best photographic conditions too.

Pro Tip

Instead of rushing to take a photo, open your camera app and pause for a few moments before taking your first shot. This allows your device time to improve its position estimate.

For best results:

• Enable Precise Location permissions for your camera app.
• Leave Wi-Fi enabled, even if you are not connected to a network. Your device can use nearby Wi-Fi signals as an additional positioning aid.
• Ensure Location Services are switched on.
• If possible, allow your device a clear view of the sky.

A Simple Workflow for Better Accuracy

Try this sequence when recording a plant:

1. The Wide Shot

Capture the entire plant from a distance, including its surroundings.

2. The Mid Shot

Move closer and take a second image, then perhaps another from a different angle.

3. The Detail Shot

Finally, move in for close-up photographs of flowers, leaves, bark, fruit, or other identifying features. (If the plant has a label, then take a shot of that for reference. You can delete it later.)

By the time you are taking the detail shots, your device will usually have had more time to refine its location. You'll also have a useful photographic record showing exactly where the plant sits within the landscape, making it easier to relocate in the future.

Understanding GPS, Mobile Networks and Wi-Fi

Many people assume GPS alone determines their location, but modern devices use a combination of technologies.

• GPS/GNSS satellites provide the primary location data.
• Mobile networks can help estimate position and speed up location fixes.
• Wi-Fi positioning uses databases of known Wi-Fi access points to help determine location.
• Device sensors such as compasses and motion sensors help improve positioning.

It is worth noting that a portable Wi-Fi hotspot does not normally improve GPS accuracy. Wi-Fi positioning only works when a device can recognise nearby Wi-Fi networks that already exist in location databases. Carrying a personal hotspot around a garden will not usually provide any additional location benefit.

iPads and Tablets: An Important Difference

Not all tablets contain a true GPS receiver.

Wi-Fi-Only iPads

Wi-Fi-only iPads do not include dedicated GPS hardware. Instead, they estimate their location using nearby Wi-Fi networks and internet-based positioning services. In large gardens, parks, arboreta, or rural locations, this can sometimes result in poor accuracy or no reliable location at all.

Cellular iPads

iPads with cellular capability include a dedicated GPS receiver. Importantly, GPS works even if no SIM card is installed. Many users purchase Wi-Fi-only models without realising this difference.

If accurate outdoor mapping is important, a cellular-capable iPad will usually provide much better location information than a Wi-Fi-only model.

External GPS Receivers

For users with older phones, Wi-Fi-only tablets, or devices that struggle to obtain accurate fixes, an external Bluetooth GPS receiver can be a useful upgrade.

Devices such as the Garmin GLO 2 connect wirelessly to phones and tablets and provide their own satellite positioning data. These receivers often feature larger antennas and better satellite reception than older mobile devices.

External GPS receivers can be particularly useful for:

• Wi-Fi-only iPads
• Older smartphones
• Large gardens and estates
• Users working in remote locations with limited connectivity

How BotanicalMapper Uses Your Data

When you upload images to BotanicalMapper, every photo retains its own unique GPS coordinates.

When you select an item's marker on the map and zoom beyond level 19, grey numbered dots appear around the main marker. These dots show the exact location where each individual photograph was taken. Click any dot to view the corresponding image.

When you create a new Plant or Landmark from a group of photos, BotanicalMapper automatically analyses the locations of those images and calculates the most appropriate position for the main map marker.

Understanding Map Limitations and Overlays

When working with digital maps, there are a few built-in inconsistencies to keep in mind.

The 2D Projection Effect

Because the Earth is being displayed on a flat screen using a map projection, geometry can become distorted. Measurements near the equator differ slightly from those taken at higher latitudes. This can affect scale readings and calculated areas. All digital measurements should be treated as approximations.

Base Map and Imagery Shifts

You may occasionally notice background features move slightly when changing map styles, enabling 3D terrain, or viewing historical imagery. This is a normal consequence of different imagery sources, viewing angles, and alignment processes.

Looking Ahead

Location technology continues to improve rapidly. Many modern smartphones now support multiple satellite systems and advanced dual-frequency GPS, allowing them to achieve impressive accuracy under open skies.

For most BotanicalMapper users, a modern smartphone will provide excellent positioning. For those using older devices or Wi-Fi-only tablets, an external Bluetooth GPS receiver remains an affordable way to improve mapping accuracy and create more reliable plant records.

While BotanicalMapper has been designed to make the best possible use of your location data, we always recommend using your own judgment when determining the final placement of important markers.