Plan the spatial data collection route for panoramic cameras

This guide aims to standardize the path planning process for Mega Block. By designing a scientific collection route, it ensures that on-site data collection meets principles such as collecting everything that should be collected, closed-loop, and loop closure, thereby improving mapping accuracy, positioning effects, and ensuring the best AR experience.

The final deliverable is a collection route planning video, which is used to guide on-site operations.

Before starting

Before planning, it is necessary to prepare a floor plan and drawing tools.

Obtain a floor plan of the collection area

Acquire a floor plan of the collection area through the following methods:

• Mainstream map platforms

  Use mainstream map platforms to obtain a floor plan or satellite map. Ensure the map is zoomed to the highest level (largest scale) to capture detailed internal road maps and building outline information.

• Provided by property management

  For scenarios such as tourist attractions, indoor shopping malls, or exhibition halls, you can also use floor plans (CAD) provided by the property management.

Save the image: Export and save the obtained floor plan in a high-resolution image format (PNG or JPG) locally. This file serves as the foundation for subsequent path drawing.

Important

The more detailed and accurate the road information in the floor plan, the higher the precision of subsequent path planning and on-site operation efficiency.

Example: Floor plan of Shanghai Changtai Plaza obtained through a map platform.

Prepare drawing route tools

The output of route planning should reflect the dynamic process of drawing the route. It is recommended to use the built-in tools of the operating system for drawing and recording.

• Drawing and annotation tools:

  • Windows: Right-click the image and select Photos to open it, then click the Edit button at the top to enter annotation mode.
  • macOS: Double-click the image to open it in Preview, then click the Markup icon in the toolbar.
  • Mobile (iOS/Android): Use the built-in Edit -> Markup feature in the system gallery.

• Screen recording tools:

  • Windows: Open the built-in Snipping Tool, switch to Video mode (camera icon), and click "New" to select the recording area.
  • macOS: Press the shortcut Cmd + Shift + 5 and select "Record Selected Portion."
  • Mobile: Use the Screen Recording feature in the system control center for real-time recording.

Tip

Regardless of the tool used, ensure the recording captures the complete process from "starting to draw" to "finishing."

Determine the acquisition scope

Before officially planning the route, it is necessary to first determine the acquisition scope. Below is an example demonstrating the process:

1. Locate the area: Search for the target landmark (e.g., xx mall, xx park, xx museum, etc.) on the map platform.

2. Define the boundary: Refer to the physical outline or administrative dotted lines displayed on the map to clearly define the area to be acquired (e.g., within the dotted lines in the figure).

3. Measure the dimensions: Use the built-in measuring tool on the map platform to measure the length and width of the target area.

4. Calculate the area: Estimate the total working area based on the measured data. For example, the area in the figure is approximately 340 meters long and 270 meters wide, with a total working area of about 90,000 square meters.

Collection route principles

To ensure the final mapping effect, the following five principles must be followed when planning routes and conducting on-site collection.

Principle one: Complete collection in a single session

• Single-session completeness: When conditions permit, strive to complete a full collection of the target area in a single session. If separate collections are unavoidable, ensure that the effective operation duration of each session is no less than 80 minutes (no less than 40 minutes when using only the built-in battery).

• Duration limit: The collection duration is limited by device power supply and system processing capacity. Strictly refer to the following table:

  Power supply solution	Duration limit
  External power bank (recommended)	128 minutes
  GoPro Max built-in battery	60 minutes

  Warning

  • Storage space: To collect 128 minutes of video, reserve at least 64 GB of storage space.
  • Overheat protection: When the temperature exceeds 30°C, remove the GoPro Max built-in battery and only use a power bank to prevent the device from overheating and shutting down.
  • Area estimation: The 128-minute maximum duration can cover approximately 90,000 square meters (300m × 300m).

• Additional requirements for outdoor collection:

  • After turning on the GoPro Max, wait 2 minutes for GNSS (Global Navigation Satellite System, such as GPS, BeiDou, etc.) signal initialization before starting collection.
  • The starting point must be chosen outdoors within 3 meters of a landmark building, and the device should face that building.

Principle two: Collect all that should be collected (core principle)

• Definition: All publicly operated areas within the operation boundary must be included in the collection scope.

  Important

  User perspective judgment method

  When planning or making on-site judgments, put yourself in the shoes of the end user.

  • Scenic spot \(\rightarrow\) Tourist
  • Shopping mall \(\rightarrow\) Customer
  • Hospital \(\rightarrow\) Patient/Visitor

  Any area that this identity might reach must be included in the collection scope.

• Open area coverage: Since the GoPro Max's clear collection range is 3 meters on either side of the path, when encountering open areas, manually increase the paths to ensure the area is fully covered in high definition, with no more than 6 meters between paths.

  

  The open square in the image is covered by a grid-like collection path with 6-meter intervals.

  

  The pedestrian street in the image, which is wider than 6 meters, is collected in a looped form (like a ladder-shaped nine-link) with left and right paths.

Principle three: Loop closure (Very important)

• Core metric for high-quality data: The proportion of paths traversed twice in the total path. The higher the proportion, the stronger the ability to eliminate cumulative errors and the better the mapping quality.

• Planning strategy:

  • Wide roads (≥6m): Perform a loop (draw a circle) approximately every 30 meters, and adjacent "loops" must have one overlapping edge.

    Important

    Slow down when turning and take as wide an arc as possible. Rapid on-the-spot turns may cause the loop to fail!

    The video demonstrates the loop closure method for four consecutive areas. Each path is marked in black when traversed the first time and in green when traversed the second time, indicating high-quality image capture on that path.

    

    In a good collection result, adjacent loops share one overlapping edge, resembling plant cell walls tightly adhered together.

  • Narrow roads (<6m): No need to loop; simply stay in the middle of the road and collect data by traversing back and forth twice.

  • Collect the main framework first, then supplement branches: For larger collection areas, first traverse the complete main route to ensure overall accuracy, then enter branch routes or key points during the second traversal to collect data.

    

    The blue circles in the image mark "small branches" diverging from the main route. The complete main route should be traversed first, and branch routes should be entered during the second collection pass.

Principle four: Loop closure

Warning

Do not end prematurely: After returning to the starting point, walk an additional few dozen meters to ensure loop closure. Unclosed data will cause severe drift in map construction.

• Loop closure standard: Before ending the collection, you must return to the starting point and then walk along the initial path for at least 30 meters.

Example: The red dot is the starting point. After returning to the starting point (dashed line), you must walk along the original path to the green dot (at least 30 meters from the starting point) before ending the collection.

Principle five: On-site verification prevails

• On-site environment discrepancies: Online satellite imagery may have timeliness limitations, leading to deviations from the actual physical environment (e.g., newly added temporary structures, barriers, or vegetation changes). If the planned route is physically impassable, you need to adjust the route flexibly based on the actual situation.

• Detail supplementation: If certain detailed areas are not reflected in the planning during the collection process, to comply with the principle of comprehensive coverage, you need to flexibly adjust the route on-site and incorporate it into the collection route.

• Real-time trajectory assistance: During outdoor collection, it is recommended to simultaneously enable a mobile trajectory tracking tool (e.g., a sports app with GNSS data recording functionality) for subsequent review. By viewing the recorded walking path in real time, you can intuitively assess the currently covered area, promptly identify missed areas, and correct the subsequent route.

  This example demonstrates using the "Huawei Health App" to record the collection route.

Check the acquisition results

After the acquisition is completed, it is necessary to check whether the trajectory data recorded by the tools used during the acquisition violates the aforementioned acquisition principles (especially the core principle of comprehensive coverage). If the deviation is significant, it is recommended to reacquire to avoid affecting the subsequent mapping effect.

Example: The acquisition trajectory recorded by the mobile trajectory tracking tool.

You can also view the trajectory map of the current acquisition route by clicking preview trajectory in the corresponding mapping task under Mega Block > Block mapping > management on the far right of the corresponding project in the cloud services section on the left side of the EasyAR development center.

If there is no GNSS data for indoor acquisition, after completing the Mega Block mapping with the acquisition data, you can also view the trajectory of the acquisition route in the mapping management of the development center.

If outdoor acquisition includes GNSS data, the acquisition route trajectory in the development center can also correspond to the map. (GNSS information may have some offset, which is normal.)

Suggested division of labor

If you are facing a large-scale collection task or need to (simultaneously) go to multiple different areas for image collection, you can refer to the following team division of labor:

• Technical personnel: Design the collection path based on the floor plan and the collection principles described in this document, and record the planning video. After the collection is completed, check the collection quality based on the recorded trajectory during the collection.
• Collection personnel: Perform on-site collection operations according to the planned video, making minor route adjustments based on the actual situation. During the collection process, use a trajectory tracking tool to record the movement path, which helps prevent missed collections and allows for post-collection review.

Tip

The division of labor is not a fixed requirement. You can flexibly adjust it according to your team's actual manpower situation.

Next steps

• Learn how to plan multi-image fusion acquisition.
• Learn acquisition methods.