Rollmetry App Support

App: Rollmetry
Developer: HEBEI SNDAS SURVEY AND DRAW CO.,LTD.
Last Updated: November 5, 2026
Support Email: service@sndas.com

Before You Start

Rollmetry is a companion application for compatible Bluetooth measuring wheels. Its functions include device connection, distance and area measurement, track calculations, calibration, measurement record management, background images, and file export.

The supplied measuring wheel uses the Bluetooth device name Rollmetry-BLE. Live measurement requires a compatible measuring wheel and a working Bluetooth connection. A matching device name or Bluetooth capability alone does not guarantee compatibility with Rollmetry. If you are unsure whether your wheel is supported, email support with its model and relevant product details.

Available functions, permission prompts, and screens may differ by App version, operating system, and device. The current version does not require an account.

Bluetooth Connection and Troubleshooting

Turn on your measuring wheel and check that it has sufficient battery power.
Enable Bluetooth on your phone or tablet and place it near the wheel.
Open the Bluetooth device page in Rollmetry, grant the requested permissions, and scan for devices.
In the scan results, select the measuring wheel named Rollmetry-BLE and wait for the connection to complete. If multiple devices have the same name, turn off the other measuring wheels before scanning again and connecting to the intended device.

If the wheel is not found or the connection fails, check the following:

Device status: Ensure the wheel is powered on and available for connection. If another phone or application is using it, disconnect that connection first.
Device name: The supplied wheel should appear as Rollmetry-BLE. If multiple devices have this name, turn off the others to avoid connecting to the wrong wheel.
Range and interference: Move closer to the wheel and reduce obstructions and interference from nearby wireless devices.
Android 12 and later: Check that Rollmetry has Bluetooth or Nearby Devices permission.
Android 11 and earlier: Check that the location permission required for Bluetooth Low Energy scanning has been granted. Some devices also require system Location services to be enabled. This operating-system requirement does not mean that Rollmetry records your geographical location through location services.
iOS: Check that Bluetooth access is enabled for Rollmetry in system settings. Bluetooth scanning does not require location permission for the App.
HarmonyOS: Check Bluetooth availability and authorization. The current App Bluetooth flow does not actively request approximate location permission.

After checking these items, stop the current scan and use the App controls to scan or connect again. If the problem persists, record the error message and contact support.

Calibration and Measurement Preparation

Different calibration functions require different actions. Follow the instructions on the relevant App screen and distinguish stationary motion-sensor calibration from wheel-circumference calibration.

Stationary motion-sensor calibration: When stationary sampling is requested, keep the phone or tablet running the App stable. Avoid movement, rotation, or vibration until the App indicates completion.
Wheel circumference and distance calibration: If the workflow asks you to roll the wheel, move it along the known reference distance and enter or confirm that distance as instructed. This calibration cannot be completed by keeping the wheel stationary throughout.
Configuration: Before measuring, check the units, wheel circumference, connection status, and relevant measurement settings.

If results appear inaccurate, check calibration, wheel circumference, surface conditions, wheel slippage or loss of contact, phone orientation, and operating technique.

Measurements and Records

Rollmetry calculates distance, tracks, area, and related results using measuring-wheel data, mobile-device motion sensors, App settings, and user input. Measurement tracks are not geographical tracks generated through GPS positioning.

Complete the measurement and saving steps shown in the App, and check that any results you need to retain appear in your saved history. Records are stored locally and can be viewed, edited, or deleted through the available App functions.

Rollmetry is a measurement assistance tool. Verify results before using them for important decisions or professional work. Where certified or legally recognized measurements are required, use equipment and procedures that meet the applicable requirements.

Background Images

You can use the image-selection function to choose a measurement canvas background. The App may store a local copy for background display and does not modify the original image in your photo library.

If an image cannot be imported, check that the selected file is accessible and opens normally, and review any system messages or authorization requests. Selecting a lower-resolution image may reduce decoding and memory requirements.

File Export

Rollmetry supports measurement exports in formats including PNG, PDF, XLSX, and DXF. Available options depend on the screen and App version.

Open a measurement result or saved record that provides an export function.
Select export, the required format, and any relevant options.
Use the system saving interface to choose the filename and destination.
Check the destination after saving and open the file with an application that supports its format.

If system saving is unavailable, the App may save the file in an available local export directory. Check the saving result or path displayed by the App.

If saving fails, check available storage space, destination availability, and any sign-in or network requirements of the destination service. When you select a cloud drive, subsequent upload and synchronization are handled by that service.

Exporting does not automatically send records to support. You may share saved files through other applications. Before sharing, check whether the file contains project names, background images, or other information you do not wish to disclose.

Local Data, Backups, and Deletion

The current version has no accounts or App-operated cloud synchronization service. We generally cannot remotely recover measurement records stored only on your device.

Important records: Export them and keep copies in a location you manage.
Android: The current version disables system application backup and uses rules to exclude App data from system cloud backups and system device transfers. Independent manufacturer transfer tools and existing backups are managed by the relevant systems or services.
iOS and other platforms: Inclusion in system backups or device transfers depends on the operating system, platform rules, and your settings.
Deleting records: Use the available in-App deletion functions. Clearing App data or uninstalling may remove local records and settings, so export important information first.
Exported files: Deleting records or uninstalling the App does not necessarily remove files saved elsewhere. Manage those files at their destinations.

Do not use clearing App data or uninstalling as the first troubleshooting step, as this may remove records you have not exported.

Contact Support

If these instructions do not resolve your issue, email service@sndas.com.

To help us investigate, please include:

Your measuring-wheel model and firmware version, if known.
Your phone or tablet model, operating-system version, and Rollmetry version.
Whether Rollmetry-BLE appears in scan results, and the connection status or error message.
The action being performed and steps that reproduce the problem.
The complete error message and any relevant screenshots you choose to provide.
Whether the problem is consistent or intermittent, and what you have already tried.

Send only information needed for troubleshooting. Remove or obscure unrelated personal or confidential information from screenshots and exported files. We will not ask for your device passcode, account password, or verification codes.

Developer / Operator:
HEBEI SNDAS SURVEY AND DRAW CO.,LTD.
河北圣达斯测绘工具有限公司