Rollmetry Privacy Policy

Effective Date: November 5, 2026
Last Updated: November 5, 2026
Developer / Operator: HEBEI SNDAS SURVEY AND DRAW CO.,LTD.
Chinese Legal Name: 河北圣达斯测绘工具有限公司
Privacy and Support Email: service@sndas.com

Overview

This Privacy Policy applies to Rollmetry (“the App”), provided by HEBEI SNDAS SURVEY AND DRAW CO.,LTD. (“we”, “us”, or “our”). It explains how the App accesses, uses, stores, and otherwise handles information, and how you can manage and delete that information.

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. Available functions and permissions depend on your platform and App version, including supported versions for Android, iOS, and HarmonyOS.

The current version does not require an account and does not provide advertising, analytics, or an App-operated cloud synchronization service. Measurement records, Bluetooth connection records, calibration settings, and background images are processed and stored on your device and are not automatically uploaded to our servers through the App.

Information We Process

The App accesses and processes the following information for the functions you choose to use:

• Measurement and project data: Project names, distances, tracks, areas, markers, calculation results, measurement history, and related display settings. This information is used locally for measurement calculations, track display and editing, saved records, and file exports. Measurement tracks are calculated from measuring-wheel data, motion sensors, and related calculations; they are not geographical tracks generated through GPS positioning.
• Bluetooth device information: Nearby Bluetooth device names, identifiers provided by the operating system, advertisement information, connection status, and measurement and control data exchanged with the measuring wheel. After a successful connection, information such as the device name, identifier, last connection time, and wheel circumference is stored locally for connection history, device management, and measurement configuration. Depending on the platform, an identifier may be a device address or a system-assigned identifier rather than a hardware MAC address.
• Motion sensor information: Accelerometer and gyroscope readings used locally for heading, device orientation, calibration, and measurement calculations. Related calculation results, calibration parameters, and measurement records may be saved locally as needed for these functions.
• User-selected images: Images you actively select as measurement canvas backgrounds. The App reads and processes the selected image and may store a local copy in an App-managed directory. This function does not automatically browse or upload your entire photo library and does not modify the original image in your library.
• Settings and local operational information: Language, display options, measurement configuration, and calibration parameters stored locally to preserve your preferences. The App or operating system may also generate local diagnostic information when errors occur, such as error details, operation status, or file-processing information. The App does not integrate a crash-reporting or analytics service that automatically uploads this information to us.
• Support communications: If you contact us by email, we receive your email address, message, and any screenshots, files, device details, or problem descriptions you choose to provide. We use this information to respond and investigate technical issues. Please provide only information necessary for your request.

We do not use measurement information for advertising or user profiling.

Device Permissions

The App uses permissions and system capabilities according to the platform and feature. Where system authorization is required, access is obtained through the applicable system authorization mechanism.

Android

• Bluetooth / Nearby Devices on Android 12 and later: Used to discover and connect to compatible measuring wheels and exchange measurement and control data. Bluetooth scanning is not used to infer your physical location.
• Location permission on Android 11 and earlier: Used to meet these operating systems’ requirements for Bluetooth Low Energy scanning. The App does not obtain geographical coordinates through location services or use this permission for location tracking.
• Motion sensors: Accelerometer and gyroscope readings support heading, orientation, and measurement calculations. These sensors generally do not require runtime authorization on Android.
• Image selection and file saving: System or platform interfaces provide access to images and export destinations you select.

iOS

• Bluetooth: Used to discover, connect to, and communicate with compatible measuring wheels. Bluetooth scanning does not request location permission.
• Motion sensors: System motion interfaces provide accelerometer and gyroscope readings for heading, orientation, and calibration. Access is subject to system availability and authorization controls.
• Image selection: Used to access background images you choose. Whether a photo-library authorization prompt appears depends on the operating system and selection method.
• File export: The system file-saving interface saves exported files to a destination you choose.

HarmonyOS

• Bluetooth: Used for measuring-wheel discovery, connection, and measurement and control data exchange.
• Accelerometer and gyroscope: Used for heading, orientation, and measurement calculations.
• Approximate location declaration: The current version declares approximate location permission for Bluetooth compatibility. However, the current Bluetooth flow does not actively request this permission or read your geographical location through location services.
• Images and files: Used to process background images and export destinations you select.

You can manage permissions that your operating system allows you to change in device settings. Denying or revoking a permission may prevent the corresponding feature from working.

Data Storage and Security

Measurement records and Bluetooth connection records are stored in a local SQLite database. Settings and calibration parameters are stored in local application preferences. Background images and temporary export files are stored in App-managed local directories.

The App relies on operating-system application storage isolation and permission controls to help protect local information. Once a file is exported outside the App, its protection depends on the destination, device settings, and any application or service you choose.

Local storage is not a guarantee of absolute security. Please protect access to your device and manage permissions and exported files carefully.

Android Backups and Device Transfers

The current version disables Android application backup and uses backup and data-extraction rules to exclude App data from system cloud backups and system device transfers.

The App cannot delete backups created previously or guarantee that every manufacturer’s independent backup or device-transfer tool behaves in the same way. Existing backups must be managed through the relevant system or service.

iOS and Other Platform Backups

Whether local App data is included in system backups, cloud device backups, or device transfers depends on the operating system, platform rules, and your settings. The App does not provide its own cloud backup or synchronization service.

Files exported to other locations may be backed up or synchronized separately by the system or service responsible for those locations.

File Export and Sharing

The App supports user-initiated exports in formats including PNG, PDF, XLSX, and DXF. Exported files may contain the project names, measurement results, tracks, markers, and background images you choose to include.

Files are generated locally. Temporary copies may be created during export. The App normally attempts to remove temporary files after the operation. If an operation or cleanup fails, some temporary files may remain until later cleanup, system cleanup, or removal of App data.

On supported platforms, a system saving interface lets you choose the destination. If system saving is unavailable, the file may be saved in an available local App export directory.

If you choose a cloud drive or another external storage provider, that service may upload or synchronize the file. If you later share an exported file through another application, the recipient can access its contents. These actions depend on your choices and the relevant services. The App cannot recall exported files or delete copies held by third parties.

External Webpages and Clipboard

When you open a privacy policy, support page, or company website, the App invokes the system browser or an external application. Visiting a website creates a network connection, and the website, browser, or service may process request information under its own privacy practices. The App does not automatically attach local measurement records to these webpage requests.

The App writes relevant text to the system clipboard only when you choose an action such as copying a link.

Third-Party Components and Data Sharing

The App uses software components and system interfaces for local functions, including:

• flutter_blue_plus: Bluetooth discovery, connection, and communication.
• Native motion sensor interfaces and sensors_plus: Platform-specific accelerometer and gyroscope access for local measurement calculations.
• permission_handler: System permission checks and requests.
• sqflite: Local database storage.
• shared_preferences: Local settings and calibration storage.
• image_picker: Processing images you select.
• File-generation components and system saving interfaces: Local generation and saving of measurement exports.
• url_launcher: Opening webpages and related links through external browsers or applications.

Using these components does not itself mean that information is sent to their authors. The current version does not integrate advertising, analytics, user-tracking, or automatic crash-reporting SDKs. It does not automatically upload measurement records, Bluetooth connection records, sensor readings, or background images to us or to such services through the App.

We do not sell your personal information or measurement data or use it for targeted advertising or user profiling.

When you send support emails, choose an external saving destination, or share exported files, the relevant email provider, storage service, or recipient processes that information. If we introduce services that change these practices, we will update this policy and provide additional notice or obtain consent where required.

Data Retention, Deletion, and Your Choices

• Measurement records: Generally retained until you delete them in the App, clear App data, or uninstall the App.
• Bluetooth connection records, settings, and calibration parameters: Stored locally and managed through available App functions or operating-system App-data controls.
• Background image copies: May remain with saved measurement records. When records are deleted, the App attempts to remove App-managed background images no longer referenced by other records. Files may remain if still referenced, if references cannot be confirmed, or if cleanup fails.
• Local App data: Can be removed using available operating-system controls or by uninstalling the App, subject to platform rules.
• Exported files and backup copies: Are not necessarily removed when you delete records in the App. Manage them separately at their storage destinations, backup services, or recipients.
• Support emails: Retained only for as long as needed to address your request, maintain necessary records, and meet applicable legal obligations.

The App has no user accounts, so there is no account-deletion process. We generally cannot remotely access or delete data stored only on your device. Please use the available App or system controls.

To request access to, correction of, or deletion of information you provided to us through support communications, contact service@sndas.com. We will handle requests according to their circumstances and applicable law.

Children’s Privacy

Rollmetry is a measurement utility and is not specifically designed for children. The current version does not require a personal account or profile.

If you are a parent or guardian and believe a child has provided personal information to us through support communications or similar contact, please email service@sndas.com.

Changes to This Privacy Policy

We may update this policy when App functionality, information-handling practices, or applicable requirements change. Updates will be published on this page with a revised date.

Where applicable law or platform rules require additional notice or consent, we will take the corresponding steps.

Contact Us

For questions about this policy, information handling, or privacy requests, contact:

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

Privacy and Support Email:
service@sndas.com