Text file

Control points or tie points (if ContextCapture can estimate the 3D position) can be exported to a simple text file with Name and coordinate (X, Y and Z).

Survey points text file sample:

GCP_A	315796.627695945 4869916.09237971 627.8
GCP_B	315332.029686681 4870703.80261219 738.9

ContextCapture Surveys file (XML)

All surveys data (including survey point properties, position on photos and positioning constraints) can be exported to XML format.

Tools

ContextCapture provides various tools to ease the survey points acquisition: filters or sorts, display hints, etcetera.

Photos filter

Use these options to apply filters on the list of photos.

Status filters

This filter allows to select photos according to their status for the selected Survey point.

All

Display all photos

Disables filtering according to status for the selected survey point.

Potential Matches

Display only recommended photos, on which the selected survey point may be placed.

It uses the available positioning data of the block to find the photos.

Note: In some cases, it may be interesting to process a first aerotriangulation with an approximate georeferencing based on GPS tags or on few control points to be able to take advantage of the selection mode based on block orientation, and then acquire the entire control point set more easily.

Note: Potential Matches filter works for photos with known photogroup properties and pose.

Incomplete block photos are not handled when using this selection mode.

ContextCapture takes advantage of the available block data, including the current survey data to improve potential matches estimation: on a calibrated scene, potential matches become more relevant after adding the first survey points (typically from the 4th).

In Use

Display only photos where a position is already registered for the selected survey point.

Sort

Two sorting modes are available:

Alphabetical: photos are sorted by name, alphabetically.
Distance from point: for a control point, closest photos are displayed first (ignoring rotation).

Filter by name

Allow to select photos by name.

Image display options

These options allow to control the content of the image view.

Show/hide all potential positions

Show the potential position of all survey points on the current photo.

For the selected survey point, the potential position is displayed with the placement marker (in yellow).

For other surveys points, the potential positions are displayed with orange markers.

Show/hide potential position of the current point

Enable epipolar lines display to highlight the potential matching region, or to check the survey point quality.

Note: We recommend to process a first aerotriangulation, to be able to take advantage of the selection mode based on block orientation. This will greatly ease the process of defining user tie points.

Note: The display photo filter based on block orientation works for photos with known photogroup properties and pose.