.. index:: single: Drone Survey single: DRONESURVEY (command) Drone Survey ============= Drone Survey turns a GeoTIFF DEM and an orthophoto into survey points, breaklines, boundaries, a grid and a TIN, then sends that work into the current drawing. It belongs to the Drone module. Open it from **Drone › Drone Survey**, the **Drone Survey** button on the Drone ribbon, or the command :command:`DRONESURVEY` (alias ``DSV``). The window stays open while you work in the drawing. .. index:: single: Drone Survey DEM DEM and orthophoto ------------------ **Load DEM** reads a GeoTIFF elevation grid, or builds one from a LAS or LAZ point cloud. The grid stays in this window. It is not inserted into the drawing as a DEM. For a point cloud, set the cell size and which returns to keep. Ground uses LAS class 2. All points uses every class. Class keeps one classification from 0 to 255. Lowest stores the lowest Z in each cell, which is the bare-earth value when the cloud is classified. Average stores the mean Z of the points that landed in the cell. The suggested cell is about twice the mean point spacing. A cell that would build more than 16 million cells is refused. The LAS or LAZ file stays external, and the cell size, the class and the lowest-or-average choice are stored with the session. A progress bar tracks the read, the terrain mesh, and the orthophoto. The window is shown before a saved session starts that load, so you can see the work coming in. **Load orthophoto** drapes a JPEG, PNG, BMP or TIFF across the DEM extent. The image is stretched to that extent. It is not reprojected. Loading a new DEM clears the photo, and you load it again afterwards. The view exaggerates height so flat sites still read as terrain. Elevations you pick and send are the DEM values, not the exaggerated display height. The picture on screen is a lighter mesh (the long side is capped at 400 cells). The full grid is still used for every elevation. .. index:: single: Drone Survey navigation Moving around ------------- Right-drag orbits, middle-drag pans, the wheel zooms, and left-drag pans. **Walk / Fly** (the move icon after Zoom extents) stands you on the surface where you were looking. - **W A S D** walk on the terrain. **Shift** runs. - Right-drag or left-drag looks around. The wheel steps forward. Middle-drag slides. - **F**, **Space** or **E** starts fly. **W A S D** then follow the view, **Q** descends, and **E** or **Space** climbs. Fly is faster than walk, and **Shift** is faster still. - **F** returns to a walk. Flying into the surface lands you. - **Esc** leaves Walk / Fly. Zoom extents, a new DEM, or the Point, Breakline or Boundary tool also leaves it. Orbit, pan and zoom are there again when the button is up. .. index:: single: Drone Survey points Points, breaklines and boundaries --------------------------------- Pick a tool, then click the terrain. A short drag still pans. A click stores a sample. - **Point** (``P``) stores a survey point. The number, the code from the **Code** box, and the DEM elevation are kept. - **Breakline** (``L``) draws a line the TIN must follow. Double-click or Enter finishes it. Esc drops the open line. A breakline is a forced edge. It does not clip the surface. - **Boundary** (``B``) draws a closed limit. Click near the first vertex (about two DEM cells, and never under 5 cm), double-click, or press Enter to close it. You need three vertices. Esc drops the open boundary. The side list shows how many points, breaklines, boundaries and surfaces the window holds. .. index:: single: Drone Survey grid Grid and low-pass ----------------- **Grid** (``G``) samples the DEM on the **Spacing** in the toolbar. A dot or a comma is accepted. The spacing is at least 0.001 in the DEM units. Nodes land on multiples of that spacing. Finished boundaries clip the grid. With no finished boundary, an open boundary must be closed first. With no boundary at all, the grid covers the DEM. More than 25 000 cells is refused. NoData cells are skipped, and a node within 1 mm of a point you already kept is skipped. Running the grid again replaces the grid points that have not been sent. **Low-pass** (``Shift+G``) uses the same spacing and keeps the lowest DEM sample in each cell, so vegetation on a DSM is less likely to win. A cell with no sample falls back to the elevation at the node. Regular and low-pass points share one pool, so either run replaces the other. Both are ordinary survey points and use the **Code** box. .. index:: single: Drone Survey surface Surface and contours -------------------- **Surface** (``S``) builds one TIN from the survey points, including grid points, and from the finished breaklines. You need three points, or the vertices of a breakline. One finished boundary clips the TIN to that ring. Several finished boundaries keep triangles whose centres fall inside any ring. An open boundary, and no finished one, must be closed first. Open lines are not part of the surface. The first surface is named ``Drone Surface``. Building again before you send replaces that surface and clears contours. Building again after a send creates ``Drone Surface 2`` and leaves the sent surface in the drawing. The TIN is drawn on the terrain as a light-blue wireframe. **Contour** (``C``) draws that TIN at the **Interval**. Major lines are five times the interval. More than 400 levels is refused. Contours are a picture in this window. They are not sent as their own objects, and a new surface or a new DEM clears them. .. index:: single: Drone Survey send Send to the drawing ------------------- **Send to Drawing** writes what has not been sent yet: - Survey points as civil points on layer ``DRONE-POINTS``. - Breaklines as 3D polylines on ``DRONE-BREAKLINES``. - Boundaries as closed 3D polylines on ``DRONE-BOUNDARIES``. - The TIN as a civil surface on ``DRONE-SURFACE``. The points go into a survey point group named for the surface, or ``Drone Survey`` when there is no surface yet. That group is listed on the surface definition, so the surface can be rebuilt from it later. Points you sent earlier in this window are added to the same group. The sent objects are one undo step. Anything already sent is skipped until you open Drone Survey on another drawing. .. index:: single: Drone Survey sessions Sessions -------- A session is the survey on screen: the DEM and orthophoto paths, the points, the lines, the boundaries, and the spacing, interval and code. The TIN itself is not stored. A saved surface is rebuilt from the points and lines when you open the session. Type a name in **Session** and press **Save**. Several names can sit in one drawing. **Open** loads the name in the box. **New** asks whether to save the survey on screen, then starts blank. **Delete** removes the named session after you confirm, and clears the screen. Saving the drawing writes the sessions into the IQZ. The DEM and the orthophoto stay external files. Each path is stored relative to the drawing, and the absolute path is kept as well. Opening tries the relative path first. A missing file is reported, and the surface is not rebuilt when the DEM is missing. The live window is also written when you save the drawing and when you close the form. An empty window does not wipe a session already in the drawing. Save the drawing itself to keep the sessions in the file. .. index:: single: Drone Survey keys Keys ---- These keys work while the code, spacing, interval and session boxes are not focused. Ctrl and Alt are left to the system. .. list-table:: :header-rows: 1 :widths: 18 82 * - Key - Action * - ``P`` / ``L`` / ``B`` - Point, breakline, boundary. Press again to leave the tool. * - ``G`` / ``Shift+G`` - Regular grid, or low-pass grid. * - ``S`` / ``C`` - Build the surface, or draw contours. * - Enter - Finish the open breakline or boundary. * - Esc - Leave Walk / Fly. Otherwise cancel the open chain, then leave the tool. * - ``W A S D`` - Move, while Walk / Fly is on. ``S`` does not build the surface in that mode. * - ``F`` / ``E`` / Space / ``Q`` - Fly, climb, or descend. See *Moving around*. .. note:: A point-cloud DEM is a grid in this window. :command:`PCSURFACE` still builds a TIN in the drawing from a point cloud that is already loaded.