This article offers a general description of how SURE handles the Project Area, the ways in which it can be defined, and the benefits of using this functionality.
The Project Area demarcates the region of interest in object space and thus, it must be defined in the same coordinate system as the exterior orientation of input images. Selected products will only be generated within the boundaries of the Project Area (e.g. DSM, True Ortho, Point Clouds, Meshes).
Important: Products generated by SURE can be georeferenced if a Project Coordinate System is provided in WKT format. See more information in the Georeferencing and Tiling page. page.
Specify Project Area
There are three ways to manually define the Project Area:
Define a limiting range along the X, Y, and Z directions. Specify minimum and maximum coordinate values when setting up a project or through the Advance Configuration panel. See Region of Interest
Specify a Shapefile (*.shp) containing a 2D domain which can potentially be defined by multiple 2D polygons. See Shapefiles
Combinations of the above can be used to control the tiling scheme (e.g. shapefile + limiting X/Y/Z range). See Georeferencing and Tiling.
Optionally, an initial terrain height can be inputted in combination with a 2D area (shapefile or max-min limits). See Region of Interest
Note. If no Project Area is manually defined, SURE will automatically compute a 3D bounding box, based on the data collected during the Analysis processing step. This bounding box is the most extended domain in which the user can expect results.
Functionality / Benefits
Selection of Input Images
SURE can automatically select the input images that "see" the Project Area if a bounded volume (2D Area + Z range) or a 2D area coupled with a terrain height is specified. Furthermore, SURE performs an image masking, such that only pixels that cover the Project Area will be matched. This feature ensures only the necessary data is used, minimizing processing time and disk space required. Shapefiles with single or multiple polygon features are supported.
Tiling of Results
Once the Project's processing area is set, its rectangular bounding box will determine the tiling scheme for the results. The tiles for the individual products will be aligned to the upper left corner of this bounding box (North-West). Note that not all tiles may necessarily exist, only those that overlap with the processing area and contain actual data. The user may expect to find results in this region, as long as the input images cover it sufficiently in terms of photogrammetric requirements.
Border quality and consistency
A buffer region (“padding”) is considered along the edges of the Project Area to ensure quality preservation. The additional data generated in this buffer region is used internally to guarantee geometric correctness; however, the final products only contain data falling within the Project Area.
This benefit from padding is also seen in the case of Distributed Processing. The same concept is applied around the area of each sub-project such that there is consistency and smooth transition between them.
It is recommended to define the Project Area whenever possible. Thanks to the automatic image selection and image masking feature, a project’s processing time can be significantly reduced. Common use-cases include:
A manual specification of the Project Area is almost always applicable, as photogrammetric flights usually capture a somewhat extended area around the actual region of interest. This means there will be an overhead of data to be processed that can easily be discarded.
With the use of Shapefiles, it is possible to follow complex political boundaries, specify multiple separate areas of interest, or specify areas with 'holes' to exclude sub-areas within the area of interest.
Because the input images will be automatically selected from the full dataset, tests can be performed rapidly on small areas, on full resolution, to find the best parameters and for prompt Quality Inspection.