The Oblique Viewer widget displays images in a native coordinate system, providing a natural view from the camera location, using the image coordinate system (ICS) in ArcGIS. Oblique images are displayed in a native ICS to avoid distortion caused by projecting them to a geographic coordinate system or projected coordinate system. The widget allows the user to view, zoom, and pan around the oblique image view, or switch angles to view an area of interest from another camera perspective.
Configure the Oblique Viewer widget
This widget can be set to open automatically when an app starts. Hover over the widget and click the Do not open this widget when the app starts button to change the setting to Open this widget automatically when the app starts. (For widgets that you need to add to the app first, you can turn on this option after configuring the widget.)
- Hover over the widget and click the Configure this widget button to open the configuration window.
If you need to add the widget to the app first, click a widget placeholder on the Widget tab. In the Choose Widget window that opens, select the widget and click OK.
- Optionally, click Change widget icon if you want to replace the default icon for this widget. A file explorer window appears, allowing you to choose a local image file to use as the widget icon.
- Click the Select the Layer drop-down list to choose the image service layer (from the input web map) to use with the widget.
The oblique image service must be based on a mosaic dataset, configured using the Frame Camera raster type with orientation metadata about each input image.
The Frame Camera raster type includes two specific fields that must be present: Elevation and Azimuth, referring to the view direction of the camera, expressed as angles measured in degrees. Camera elevation set to 0 means aimed at the horizon, and angles above the horizon are positive and below the horizon are negative, so an angle of -90 means aimed at nadir. Camera azimuth set to 0 means the top of the image is aimed at true north in the specified coordinate system, and angles are measured positive clockwise (for example, 90 = east).
- Click the Elevation Field drop-down list to choose the field that defines the Sensor Elevation from the list of available fields.
- Click the Azimuth Field drop-down list to choose the field that defines the Sensor Azimuth from the list of available fields.
- For Search Radius, set an absolute value to use as a radius around the dropped pin on the main map.
This allows you to increase the area of interest associated with a dropped pin and view the oblique images that contain that area. The default value set is 0 meters.
- In Select the List Info Fields, choose the info fields to be displayed in your raster list.
- Check the Show Thumbnail in Raster List option to enable thumbnails in the raster list in the widget.
- Check the Synchronize Main Map option to automatically synchronize the nadir map with any change in the extent made to the oblique map.
The nadir map may be the basemap, but typically it is a second image service in the input web map, showing a dynamic orthomosaic of the nadir images captured at the same time as the oblique images.
- Check Enable Distance and Area Tools to show distance, angle, area, and perimeter measurement tools in the oblique map window.
- Click OK to save and close the configuration window.
Use the Oblique Viewer widget
When initialized, the Oblique Viewer widget displays the images in Nadir view.
- Click the widget button to open the widget that contains the Oblique map.
- The rotational gauge at the lower right side of the widget panel allows the user to choose the direction of the oblique image to be displayed. The blue squares on the sides of the dial indicate the directions in which images are available. Click the blue squares to switch the view of the image to the corresponding direction.
- Click the circle in the middle of the rotational gauge to switch the images displayed in the widget panel to Nadir mode.
- The toolbar at the top of the widget panel includes the following actions. Choose one of them to explore the image.
- Click Locate area to drop a pin on the main map. This allows you to locate an area and view the oblique images associated with it.
- Click Clear all graphics to clear all the graphics displayed on the main map.
- Click Zoom to extent to zoom to the extent of the raster selected in the Oblique mapwindow.
- Click Synchronize map to manually synchronize the extent of the Nadir map with any changes in location made to the Oblique map. This button is available in the widget panel only when the Synchronize Main Map option is disabled in the configuration window.
Click Show raster list to list all the raster images available for the displayed map extent. The list can be filtered in the rotational gauge of the widget, depending on the angle selected.
- Click the Measure button to select a height measurement operation and unit of measurement from the drop-down list:
- Height: Base to Top—Calculates the height of a structure by measuring from the base of the structure to the top of the structure. Measurements are assumed to be perpendicular to the base. The line being measured along the building must have its end point directly above the start point.
- Height: Top to Top-Shadow—Calculates the height of a structure by measuring from the top of the structure to the top of structure's shadow on the ground. The points on the structure and its shadow must represent the same point.
- Height: Base to Top-Shadow—Calculates the height of a structure by measuring from the base of the structure to the top of the structure’s shadow on the ground. The point in the shadow must represent a point on the structure that is perpendicular to the base.
- Distance and Angle—Calculates the distance and azimuth angle of an interactively drawn line segment.
- Area and Perimeter—Calculates the area and perimeter of an interactively drawn polygon.
- Linear Units—Allows you to configure a preselected unit of measure for linear measurement. The options include the following:
- Nautical Miles