HiRISE Operations Center

Department of Planetary Sciences
University of Arizona
Tucson, Arizona

HiView User's Guide


HiView is a software application designed for displaying and exploring the details of image data.

This User's Guide for HiView is intended to help those new to HiView get started using the software, and to provide a Reference to the components, controls and functioning of the application. Many users will already know how to install the software and will be eager to start right in. HiView was designed with this spirit of exploration in mind, so users are encouraged to explore HiView's capabilities while exploring the image data it presents. HiView was also designed with the power user in mind, so the Reference provides details on how to use the shortcut controls. Along the way an explanation of some of the many concepts involved in scientific image data manipulation is included to help understand the purpose of the tools and how they might be used to gain an insight into what the image data can reveal.

Image Files

HiView was developed to provide a convenient means to explore the large observation image data sets returned from Mars by the HiRISE camera on board the Mars Reconnaissance Orbiter spacecraft. But HiView is not limited to exploring HiRISE image data products. It may be used to examine image data stored in a wide variety of standard image file formats.

The Technical Details Addendum provides information on HiView support for image file formats.


HiView is able to read many conventional image file formats such as PNG, TIFF, JPEG, etc. These formats are generally intended to contain image data in a form that can be efficiently displayed on a computer screen with good viewing quality.

Computer displays (with very rare exceptions) work with three bands, or channels, per image pixel of data - usually red, green and blue (plus a possible alpha band for controlling overlay or transparency effects) - that are combined on the screen to produce the visible color spectrum. Each image band has an 8-bit data precision which is quite adequate to produce a sufficient range of specific colors so that when the three bands are combined what appears to be a continuous color spectrum is visually produced.

In many cases the image data has been compressed to provide faster network transmission. The compression may be "lossy" - some image data information is lost - to increase the effectiveness of the technique, but usually not to the point of significantly degrading the viewing quality when the data is decompressed to restore the intended image data value.


For scientific image data, using file formats that enable high precision values to be stored with no information loss is important. However, data compression is also important when the size of the image is quite large. To meet these needs the HiRISE Project chose to use the JPEG2000 technology to store image data in standard JP2 format.

A JP2 file contains metadata describing the image data which is stored as compressed - either lossy or lossless - codestreams. A JPEG2000 codestream is based on a Discreet Wavelet Transformation (DWT) of the original image pixel values. This codestream has characteristics that enable it to be selectively decoded for all or part of the full image area, at less than the original image resolution, and at less than the full quality level of the original image while still maintaining high quality viewing fidelity.

HiView takes particular advantage of the JPEG2000 codestream characteristics by only rendering that area of the image needed for the display (and any look-ahead rendered areas) at the resolution needed for the current image scaling factor; the entire image does not need to be loaded into the computer's memory. This enables very large images to be explored which would otherwise be too big to fit into the computer's memory or take a very long time to transmit over the network for remote access.

and Remote

Image data loaded into HiView may be obtained from local files accessible by the host computer's filesystem, or from remote files accessible over the network from a server system.

HiView is able to load and render local files very quickly. Even very large JP2 files will be rendered from a local file to the display quickly by taking advantage of the JPEG2000 technology and using all the processing power of the host system; on multi-processor systems all of the processors are used in parallel to render the codestream.

HiView is able to access source files that use conventional image formats remotely from standard HTTP web servers. Because HTTP servers are stateless - a request from a client produces a single response with no information being retained about the client - the entire image will be copied over the network into memory where HiView will render the data for display and manipulation.

For JP2 files HiView is capable of employing the JPEG2000 Internet Protocol (JPIP; Part 9 of the JPEG2000 standard) for interacting with a JPIP server to obtain metadata and codestream segments as needed. HiView acts as a client to the JPIP server by establishing a persistent session connection in which the server retains information about the state of the client during a session. This enables the JPIP server to help optimize the data transmission requirements to only what is required by the HiView client to render the image area at the resolution of interest to the user.

For example, when the entire image is to be rendered at a small scale (low resolution) to view a large image in the relatively small area of the HiView display viewport, only those segments of the codestream needed to render the image up to the resolution specified by the HiView client will be transmitted by the JPIP server. Also, when increasing the image scaling (zooming in) the JPIP server will know if the client already has some of the codestream segments required for rendering the image region at a higher resolution - from having already obtained the codestream segments to render the region at a lower resolution - and so will only transmit the additional codestream segments that are needed. Similarly, when only a relatively small area of the image is to be rendered by HiView, the JPIP server will only transmit the codestream segments relevant for the requested image area, and only those that the client does not already have.


In addition to displaying image data HiView provides tools to facilitate image data exploration in detail, including navigating through the image data, examining its statistical distributions, and manipulating the relationships between the source data and the image that is displayed. These capabilities are intended to be easily accessible for those using HiView for scientific purposes, but unobtrusive when HiView is used for solely for the purpose of image viewing.

HiView does not provide complex analytical capabilities; there are many image data analysis packages intended for use in various analytical contexts. HiView is intended to provide a means to explore the details of image data, especially as a quick and convenient means to explore very large, high precision, image data sources accessed remotely.

Quick Start

This is a quick guided tour through HiView. Do what is described in each step, below, in the order presented for an introduction to the basic HiView operations and capabilities. Follow the links to the Guide's Reference sections to find complete descriptions of the various other ways of doing the operations and to learn more about the capabilities of the tools. After completing the tour further explore what HiView has to offer, with the help of the Reference, to explore image data.

It is assumed that the system on which HiView is run has a connection to the internet.

Install the application from its distribution file.

Run HiView by clicking (or double-clicking) on the HiView desktop icon, or entering the "HiView" command in a terminal window on a Linux system. The HiView Main Window should appear after a short wait.

Open a HiRISE image by first selecting an image of interest on the HiRISE web site; such as the example image used in the Guide. Scroll down the web page to the Image Products section. Under the JP2 Quicklook Download heading, next to the RGB color label, click and drag the underlined link onto the HiView Display Viewport. Wait for the image to be opened and rendered (this may take a little while, depending on the available network bandwidth, to fetch the image data). The Source Location field should now contain the JPIP URL for the source image data.

Display the Image Info by selecting the Image Info entry in the View menu. The source data location and image values will be reported as the Reticule Cursor moves over the image.

Display the Navigator tool by selecting the Navigator entry in the View menu. Enlarge the main window vertically by dragging its bottom edge (or the lower-right corner on Mac systems).

Change the image Scale by dragging the thumb on the scale slider to the right of the Display Viewport. Set the scaling factor to 0.5 by entering this value into the Image Scale field of the Navigator Image Details panel Geometry section. Wait for the Activity Indicator to disappear which indicates that fetching the remote data and rendering it is done.

Scroll the Display Viewport to a new location by dragging the thumb on the horizontal scroll bar below the viewport and the vertical scroll bar to the right of the viewport. Set the Navigator Image Details panel Geometry section Region Origin field values to 940 X and 16715 Y.

Display the Statistics tool by selecting the Statistics entry in the View menu. Dismiss the Navigator Tool Dock by clicking the X button in the upper right corner of the tool's panel.

Apply the default Contrast Stretch by selecting the Default Contrast Stretch entry in the Data Map menu.

Display the Data Mapper tool by selecting Data Mapper in the View menu. Drag the thumb of the slider in the Saturation Bounds Histogram Percents Lower section up a little (Settings field values of about 10 should be fine) to significantly increase the image contrast. Dismiss the Data Mapper and Statistics tools by selecting their checked entries in the View menu.

Save a copy of the image region in the Display Viewport by selecting the Save... entry in the File menu. Enter 1.0 into the Image Size Scale field to save the image region at full resolution. Select the image file format from the Files of type drop-down list. Enter a name for the output file in the File name field and click the Save (orbutton. A Saving Image window will appear and remain active until the output image has been rendered and written.

Select the Quit entry from the File menu, or the HiView menu on a Mac system, to quit the HiView application. The next time HiView is run on the same system it will restore its last window position and size, and open the last image being viewed unless the settings for these features are changed in the Preferences General Layout section.