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Project Point Method

The Project Point method (also known as Distance & Bearing) is a surveying technique that allows you to place features on the map by specifying a horizontal distance and true bearing from a known source location. Instead of relying solely on GPS to position a point, you establish a reference point and then calculate target locations using trigonometric projection - the same principle used in traditional surveying with a total station or laser rangefinder.

Mapit GIS Professional - Project Point Method

This method is particularly useful when:

  • Surveying features that are not directly accessible (e.g. trees across a river)
  • Using a laser rangefinder for accurate distance measurements
  • Building geometry from a fixed base station using traditional surveying techniques
  • GPS accuracy is insufficient for the required precision

Enabling the Feature​

The Project Point method must be enabled before use.

  1. Open Settings > Survey Settings
  2. Scroll to the Distance & Bearing Method section
  3. Toggle Distance & Bearing Method to On

Once enabled, tapping the Add button on the map screen will open the Project New Point dialog instead of placing a point directly at the map cursor or GPS location.

tip

When you disable the Distance & Bearing Method, the rangefinder setting is also turned off automatically.

Project New Point Dialog​

When you tap the Add button with the Distance & Bearing method enabled, the Project New Point dialog appears. It has three sections: source selection, measurement input, and a base point option.

Selecting the Source Location​

Choose where to project the new point from:

SourceDescription
Current GPS / Map CursorUses your current GPS position (if GPS is active) or the map cursor location
Last PointUses the coordinates of the last point you added (only shown if a point was previously added)
Base LocationUses a named base point stored in the project (only shown if base points exist)

When Base Location is selected, a dropdown appears allowing you to choose from the available base points in the current project.

Entering Measurements​

Provide the following values:

  • Distance to new point (meters) - the horizontal distance from the source to the target. Must be greater than zero.
  • True Bearing (degrees) - the azimuth from the source to the target. Must be between 0 and 360.
caution

The distance must be entered in meters and the bearing in degrees (true north). If your rangefinder reports values in other units, convert them before entering.

Setting as Base Location​

Check Set as Base Location to save the projected point as a named base point. This allows you to use it as the source for future projected points, enabling you to chain measurements from one base to the next.

Working with Base Points​

Base points are named reference locations stored within the project. They allow you to establish a fixed origin and project multiple points from it.

Creating a Base Point​

  1. Tap Add to open the Project New Point dialog
  2. Check Set as Base Location
  3. To create a base at your current position, set both distance and bearing to 0
  4. Tap Save

The base point is automatically named (e.g. BASE 1, BASE 2) and stored in a dedicated base points table within the GeoPackage.

Using a Base Point​

  1. Tap Add to open the Project New Point dialog
  2. Select Base Location as the source
  3. Choose your base point from the dropdown
  4. Enter the distance and bearing to the target
  5. Tap Save
tip

The app remembers the last used base point, so it is pre-selected the next time you open the dialog.

Base Point Visibility​

You can control whether base points are visible on the map and in layer management:

SettingLocationEffect
Show Base Points on MapSettings > Survey SettingsDisplays base point markers as a map overlay
Show Base Points in LayersSettings > Survey SettingsIncludes the base points table in the layer management screen

Laser Rangefinder Integration​

Mapit GIS supports Bluetooth laser rangefinders that can automatically populate the distance and bearing fields in the Project New Point dialog.

Supported Devices​

DeviceMeasurements Provided
Laser Technology TruPulse 360BDistance, azimuth, inclination, slope distance
Trimble LaserAce 1000Distance, azimuth, inclination
CEM iLDM-150Distance, slope angle
NMEA-compatible devicesDistance, bearing (via standard NMEA sentences)

Pairing a Rangefinder​

  1. Pair the rangefinder with your Android device via Bluetooth Settings on your device
  2. In Mapit, go to Settings > Survey Settings
  3. Ensure Distance & Bearing Method is enabled
  4. Toggle Bluetooth Rangefinder to On
  5. Select your paired device from the list
caution

On Android 12 and later, the app requires the Nearby Devices (Bluetooth) permission. If you deny the permission, the rangefinder toggle is automatically turned off.

Using the Rangefinder​

Once paired, take a measurement with the rangefinder. The distance and bearing fields in the Project New Point dialog are automatically populated with the received values. If the rangefinder provides inclination data, the app also calculates:

  • Slope distance from the horizontal distance and vertical angle
  • Altitude of the projected point based on the base elevation and vertical angle

Inclination and Height Calculation​

When a rangefinder provides an inclination (vertical angle), the app performs additional calculations:

  • Height difference = horizontal distance x tan(inclination angle)
  • Target altitude = base elevation + height difference
  • Slope distance = horizontal distance / cos(inclination angle)

These values are stored with the point and can be included in exports.

Exporting Rangefinder Data​

By default, exported features only include the projected coordinates. To include the full measurement details, enable the export option:

  1. Go to Settings > Survey Settings
  2. Toggle Export range finder measurement details to On

When enabled, the following additional fields are added to exported point features:

Export FieldDescription
baseLatLatitude of the source (base) location
baseLonLongitude of the source (base) location
baseElevElevation of the source (base) location
tgtHorizontalDistanceHorizontal distance to the target (meters)
tgtBearingTrue bearing to the target (degrees)
tgtSlopeDistanceSlope distance to the target (meters)
tgtVertAngleVertical angle / inclination (degrees)
tip

These fields are only included for point geometry features. They are available in all export formats (GeoJSON, KML, GPX, CSV, Shapefile).

Step-by-Step Example​

Here is a typical workflow for surveying features using the Project Point method:

  1. Enable the feature in Settings > Survey Settings > Distance & Bearing Method
  2. Create or select a layer to collect data into
  3. Establish a base point - tap Add, check "Set as Base Location", set distance and bearing to 0, and save
  4. Survey the first target - tap Add, select "Base Location", enter the measured distance and bearing, and save
  5. Continue surveying - repeat step 4 for each target, always referencing the same base point
  6. Move the base - if needed, create a new base point at a different location and continue from there
  7. Export with measurement data - enable "Export range finder measurement details" in Survey Settings before exporting

Survey Settings Reference​

All settings related to the Project Point method are located in Settings > Survey Settings under the Distance & Bearing Method section:

SettingDefaultDescription
Distance & Bearing MethodOffMaster switch - enables the Project New Point dialog
Bluetooth RangefinderOffConnect to a paired laser rangefinder via Bluetooth
Show Base Points on MapOffDisplay base point markers on the map
Show Base Points in LayersOffInclude base points in layer management
Export range finder measurement detailsOffAdd measurement fields to exported point features