What is ImageLinker

ImageLinker is a GUI application that is built on OSSIM (Open Source Software Image Map) which allows you to view and process Geographic Information System (GIS) and remote sensing data.

Download and Installation

Windows Version

The Windows version of ImageLinker is a part of the ossimPlanet Download

Mac Version

ImageLinker Download

Linux Version

The Linux version of ImageLinker is a part of the ossimPlanet Download

Basic Navigation

Function	Operation
Pan	Select "Pan" button on top of window then left click on image
Zoom	Select the magnifying glass and then left click on image (zoom in) or hold down shift and left click (zoom out)

View Modes

Fit

The Fit function scales the entire image so that it can be viewed in its entirety, as seen on the left. In this example, the image on the right is the initial view of the Landsat image, while the left has been fitted into the view window.

Full Res

The Full Res function scales the image to full resolution, with the image centered around where the last click on the image was located. Display window on the left shows a full scaled (resolution) of a Landsat imagery. If it is just fitted, it will appear similar to the display window on the right.

Propogate

The Propogate function matches the views of the geographic data sets to the same resolution and scale as the selected window. A command is transmitted to the other windows to display in the same view as the window where the propogate button was selected.

Note: Right window is the active window. The frame on the left follows the resolution of the right window.

Edit Menu

View

In the View window, this allows you to modify the projection of the displayed image. A new projection or datum can be selected by just selecting the desired projection/datum from the drop down menus.

Image Info

The Image Info contains the geometry, projection, and vertex information about the displayed image. Each section can be accessed by clicking the respective tabs. Image geometry contains information about the image's file type, radiometry, pixel sizes, and pixel values. Image Projection contains information about the image's projection and Valid Verticies display the pixel values for the corner of the data within the file.

Position Information

Position information displays the coordinates in which the image covers. It also indicates which UTM zone the image was taken in.

Swipe Menu

This drop down menus is located within the display window. Two images that are of the same geographic area can be overlain and then compared by clicking and dragging the cursor back and forth over the image. The top layer covers and uncovers the bottom layer.

To activate swiping, another layer must be added. This can be done by selecting the "Add Layer" function within the swipe menu.

In the Layer Chooser window, select the image that you want to stack on top of the original image.

Layers can be removed by choosing the "Remove Layer" option in the Swipe Menu

Note: Make sure that both images that you want stacked on top of each other are open in ImageLinker. You cannot open another file from the Layer Chooser window.

Swiping Options:
Horizontal Swiping: Click and drag the cursor to the left and right to cover and uncover layer
Vertical Swiping: Click and drag the cursor up and down to cover and uncover layer
Box Swiping: Click and drag the cursor over the image to cover and uncover layer in a box fashion

Enhancement Menu

Band Selection

Allows you to select which bands are mapped in the output map. Grey scale selects only one band, while true color selects 3 bands for red, green, and blue. N-Band allows you to select as many bands as you want to display. Bands can also be reordered in this box.

Brightness Contrast

Allows you to adjust the brightness and contrast of the image in the display window. If there are two images in one display window, the original image loaded into that window will only be adjusted. The added image will remain the same.

Histogram Operations

By selecting this function, a histogram is computed using the data from the image. Once created, the histogram (*.his file) is placed into the same folder that the image is located at. The file name is identical to the image name.

Hue Saturation Intensity (HSI)

Provides color adjustments via hue, saturation, and intensity sliders. Changes can be made to just one channel or all channels. To enable changes made in the HSI menu, the enable checkbox must be active.

Layer Menu

Contains the contents that are related to the layers of the map

The functions that are found in the Layer Manager can also be found here. However, the mosaic function in this menu mosaics pictures in the order in which they are selected. Images selected first would be on the top, the second under that, and so on.

Merge Bands (located within the Combine submenu): Creates a new image chain that is based off the input bands from the selected image chains together.

The Combine Menu functions currently works with Landsat 7 imagery and will work with Landsat 5 imager if it is first manipulated with. The command line of imag2rr<image_filename> needs to be ran on the images before they can be properly overlain. Images will not properly mosaic together if they are not manipulated with first.

Layer Manager

Displays all of the image chains that are open within the current project. Image chains can be duplicated, deleted, mosaicked, blended, and feathered together within this box.
Note: These functions can also be found in the Combine option within the Layer Menu

Display: Brings the selected image chain display window to the front of the project window
Delete: Deletes the selected image chain and their display windows
Duplicate: Makes a copy of the selected image chain
Mosaic: Creates a mosaic in a new display window of the selected image chain

Blend: Creates a blended mosaic in a new display window of the selected image chains. Blend mosaics the pixel values in which the two images overlap.

Feather: Creates a feathered mosaic in a new display window of the selected image chains. Feather mosaics the selected images transitioning the pixel values from one image to the other where they overlap

Histogram Match

Selecting this option in the Layers menu will bring up the image chain display list.

Select the image chains to be mosaicked together and have their histograms matched. This function will created a new image chain and display the histogram matched mosaic.

Fusion

Fusion holds specialized image functions. All of the function in this submenu need to have one 3 or greater band layer and one single band layer in order to be used.

Correction

Allows you to fix the atmospheric or topographic attributes of the selected image chain.

Elevation

Hillshade: Images need to have elevation normals in order for this function to work
Normals: Creates a RGB image of the X, Y, and Z coordinates from the surface normal

Visual Chain Editor (VCE)

This function currently does not work with the most recent version of ImageLinker. The VCE is part of the ossim_qt module (the original Qt) and will only work with that one model.

Utilities

Datum Converter: This will be selectable when an image that does have datum has been opened within ImageLinker. Here one can convert the datum, with all variables being inputted by hand. There is no set datum that one can just choose from.
Unit Converter: Simply a calculator that has been built into the program to help you to easy convert units.

Window

Cascade: Cascades the image chain windows
Tile: Rearranges the windows so they tile within the project canvas
Minimize All: Minimizes all windows to the bottom of the project canvas
Restore All: Opens back up all the windows that were minimized
Maximize: Selected image chain will be maximized to the same size as the project canvas
Refresh All: Refreshes all image chains
Close All: Closes all image chains

Notes

• If a project is open, make sure to save the project. If you exit the program without saving, everything will be lost. ImageLinker does not prompt you to save prior to exiting the program.
• Even though you may have closed the window to a selected image chain, that chain is still opened within ImageLinker. It can be reopened through the Layer Manager window.