Queries ======= Gain a deeper understanding of your flight plan by using the functions available in the **Queries** tab of the :doc:`Navigation bar ` . At the top of the Queries sidebar, select one of the buttons to open the corresponding panel that provides further interaction options. .. image:: ../../pics/query/buttons.png Available tools (from left to right): #. Measurement of distances and areas #. Image position queries #. Flight line queries #. Sun elevation angle The following section explains how to effectively apply these tools. Measurement of distances and areas ---------------------------------- Distance measurement ^^^^^^^^^^^^^^^^^^^^ Determine the distance between two points on the map using the built-in measurement function. Utilize this feature not only to precisely measure distances but also to gain insights into height differentials and azimuth values for your planning and analysis needs. .. topic:: Measuring distances: #. Select the |scale| button located at the top of the secondary sidebar. #. Choose **Distance** from the available measurement options. #. In the :doc:`Workspace `, click on the starting point for your measurement. #. Move your mouse cursor across the map to your desired endpoint. #. *Value Display*: As you move the cursor, the values displayed in the secondary sidebar will dynamically update. #. End a measurement by performing a right-click with the mouse. .. hint:: In the secondary sidebar, you will also gain access to other valuable information, such as: * azimuth * coordinates of the start and end point * difference in height * slope .. image:: ../../pics/query/measure_line.png Area measurement ^^^^^^^^^^^^^^^^ |Software name| provides a useful tool to measure the extent of areas. .. topic:: Measuring areas: #. Select the |scale| button located at the top of the secondary sidebar. #. Choose **Area** from the available measurement options. #. Click on the first point of the area. A first vertex for the polygon becomes visible. #. Click all the positions to form your desired polygon. #. *Value display*: Once the polygon comprises more than two vertices, measurement values for the area become visible in the secondary sidebar. Additionally, a histogram depicting the height distribution within the specified area is presented, with a vertical line indicating the average terrain height. #. End a measurement by performing a right-click with the mouse. .. hint:: Move the vertices to make some fine adjustments to the polygon: * Click on the vertex you want to move. The vertex will become red. * Drag the vertex to its new destination. * The polygon with the dashed line and the measurement values are updated. .. image:: ../../pics/query/measure_area_statistics.png .. _image_position_queries: Image position queries ---------------------- The menu for image sequence queries offers different methods for the selection of image positions. At the bottom of the sidebar menu, there are several functions on how to proceed with the selection. .. topic:: General query procedure: #. Specify how the selection should be performed. #. Choose the query method. #. :ref:`Use the selection ` to modify your flight plan. .. list-table:: :widths: 10 30 :header-rows: 1 * - Selection method - Result * - Rectangle - Use the mouse drag to select an area with a rectangle bounding box in the map. * - Click on polygon - Select an already defined area as reference for the spatial query. * - Attribute - Define equations to make a query based on the properties of the shape. * - Image sequence - Check the space between two image trigger points on the same flight line to ensure it adequately aligns with the camera capture rate limitation. Spatial queries ^^^^^^^^^^^^^^^ Spatial queries are made with the selection methods **Rectangle** and **Click on polygon**. .. image:: ../SharedGraphics/query/image_spatial.png Select whether the function should be based on the **Image position** or its **Footprint**. Choose the geographical context from the following options: * **Inside:** All image positions/footprints will be selected if the point or footprint is entirely inside the reference area. The shape will not be selected if it touches the reference area. * **Intersecting:** Image positions/footprints that fall within or touch the reference area will be selected. * **Outside:** Image positions/footprints that fall outside of or do not touch the reference area will be selected. According to the selection method, you can then perform the query by using the mouse drag to select an area (method **Rectangle**) or by using an already defined area (method **Click on polygon**). Properties queries ^^^^^^^^^^^^^^^^^^ The **Attribute** selection method offers different selection criteria to build up a query. .. topic:: Attribute selection: #. In the *Select by* menu choose **Attribute**. #. Choose whether the function should be based on the **Image position** or its **Footprint**. #. Choose a property from the *Attribute* dropdown menu on the left. #. Select the desired operator from the dropdown menu in the middle. #. Depending on you property, enter a value (for numeric fields, e.g. height) or choose from a dropdown list (for enumerated fields, e.g. Line ID) on the right. #. For more than one constraint, add additional rows to the menu by clicking on **Add constraint**. #. To reset the constraints (e.g. to build up another query), click on **Reset constraints**. #. Click on **Make selection** to actually process the query. #. All image positions matching the query are selected and highlighted on the map in the workspace. .. image:: ../SharedGraphics/query/image_attribute.png Image sequence queries ^^^^^^^^^^^^^^^^^^^^^^ This query is used to find locations at which the camera capture rate might be insufficient. .. topic:: Image Sequence selection: #. In the *Select by* menu choose **Image Sequence**. #. Choose whether the function should be based on the **Image position** or its **Footprint**. #. In the *Constraints* menu, enter the flight speed and/or max. frames per second corresponding to the plane and camera options. #. The system automatically calculates and displays the *Max. speed* that can be flown based on the entered maximum fps value. #. Click on **Select problematic positions** to actually process the query. #. All image positions matching the query are selected and highlighted on the map in the workspace. .. image:: ../SharedGraphics/query/image_sequence.png .. _using_point_selection: Making use of the selection ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Point selections can be used for the following purposes: * Deletion of areas with unwanted image points, e.g. where no pictures may be taken. * Shortening of flight lines. * Modification of flight lines in areas where image points do not meet your requirements. Use the buttons on the bottom of the secondary sidebar to: * **Unselect** points * make an **Inverse selection** * **Delete selected items** * or **Export selection to temporary layer**, which will then appear in the layers panel. .. important:: The deletion of data points cannot be undone! Only click on **Delete selected items** if you are completely certain that your selection is accurate. If uncertain, it is advised to use the **Save as** option and save the project under a different name before proceeding to delete items. Automatic :ref:`flight line recalculation` for accidentally deleted image points is possible. Shortened flight lines, however, need to be fixed manually. Flight line queries ------------------- Flight line queries generally are performed analogous to :ref:`image position queries `. Here, a new selection method *Line* as well as the option based on *Flight line* are available. If select by *Attribute* is chosen, a larger variety of attribute options are given in the respective dropdown menu. .. list-table:: :widths: 10 30 :header-rows: 1 * - Selection method - Result * - Rectangle - Use the mouse drag to select an area with a rectangle bounding box in the map. * - Click on polygon - Select an already defined area as reference for the spatial query. * - Attribute - Define equations to make a query based on the properties of the shape. * - Line - Select specific lines by clicking and then dragging the mouse (spatial relation *inside* not available). .. image:: ../SharedGraphics/query/flight_line_query.png Know when to fly ---------------- The sun's elevation angle not only dictates the time window for the flight, spanning from sunrise to sunset, but it is also a crucial determinant for capturing high-quality images. During low sun angle degrees shadows become excessively long and thus reduce the image quality. Large sun angle degrees during mid-day can cause reflections, particularly from water bodies, that become overly intense, leading to potential issues like cross-fade. Therefore, knowing the optimal time window for the flight is essential for obtaining the best outcome. .. topic:: Determining optimal flight times: #. Select the |sun| button located at the top of the secondary sidebar. #. Choose either the button **Map center** or **Mouse click** to automatically fill out the coordinates. It is also possible to manually type the coordinates into the respective windows above the buttons. #. If applicable, adjust the *UTM time zone* by entering the offset. The *Required sun angle* diagram will update accordingly. #. In the *Required sun angle* box, enter your minimum and maximum criteria in degrees. #. The *Required sun angle* diagram, illustrating sunrise, sunset, and the minimum and maximum sun angle criteria throughout the entire year, will be updated automatically. Click on the diagram to obtain a larger image that can be copied to the clipboard. #. Move the mouse over the diagram to show the flight *time window* for individual days of the year at the bottom of the secondary sidebar. If sun angle requirements exclude mid-day times, two *time window* boxes are shown. .. image:: ../SharedGraphics/query/sun_input.png | .. image:: ../SharedGraphics/query/sun_output.png