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 view, zoom, and pan around in the oblique image view, or switch angles to view an area of interest from another camera perspective.
Configuring the Oblique Viewer widget
This widget can be set to open automatically when an app starts. To enable this feature, click the Open this widget automatically when the app starts button on the widget, which turns it dark green.
- Hover over the widget and select Configure this widget button to open the configuration properties dialog box.
- Optionally click Change widget icon if you want to replace the default icon for this widget. A file explorer window opens, 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 = 0 means aimed at the horizon and angles above the horizon are positive, below horizon are negative, so angle = -90 means aimed at nadir Camera Azimuth = 0 means top of the image aimed at true north in the specified coordinate system, and angles measured positive clockwise (e.g. 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.
- Define a Search Radius to set an absolute value as radius around the dropped pin in the main map.
This allows you to increase the area of interest associated with 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 within 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 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 the Enable Distance and Area Tools to show distance, angle, area and perimeter measurement tools within the Oblique map window.
- Click OK to save and close the configuration window.
Using the Oblique Viewer widget
When initialized, the Oblique Viewer widget displays the images in Nadir view.
- Click on the widget icon to open the widget which 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. Clicking on the blue squares will switch the view of the image to the corresponding direction.
- Click on the circle in the middle of the rotational gauge to switch the images displayed within 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 to drop a pin on the main map. This allows you to locate an area and view the oblique images associated with it.
- Click the button to clear all the graphics displayed on the main map.
- Click to zoom to the extent of the raster selected within the Oblique mapwindow.
- Click to manually synchronize the extent of the Nadir map with any changes in location made to the Oblique map. This icon is available in the widget panel only when the Synchronize Main Map option is disabled in the configuration window.
Click to list all the raster images available for the displayed map extent. The list can be filtered within the rotational gauge of the widget, depending on the angle selected.
- The measure icon allows the user to select different height measurement operations. The drop-down list allows the user to select the unit of measurement and the measure operation. The followings are the different measurement options available.
- 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