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This document describes the options for creating links to JPEG2000 images stored in the Harvard Library Digital Repository. This document is intended for Harvard curators and collection managers who need to add JPEG2000 image links to a catalog or special collection web site.

From a single JPEG2000 image in DRS, the Image Delivery Service can deliver static JPEG images on-the-fly in a variety of resolution sizes. Or, it can deliver a JPEG within an interactive web-based viewer that lets the user zoom, pan and rotate the image.

Note about captions: curators can request that captions be applied the use copies of images delivered from the DRS. Captions are generated on-the-fly and delivered to the web browser as part of the image. See the separate document Image Captions for more information.

If you have a question about delivery of JPEG2000 images, send a message to the IDS support team. If you are reporting a problem, please include in your report a description of the problem, any error message you see, and the image's url.

Which link to use

To use the JPEG2000 link options described in this document, you can append them to the native IDS link or to the URN link. Best practice is to use the persistent identifier (URN) when one is available. 

Native IDS link: http://ids.lib.harvard.edu/ids/view/839567
URN link: http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample

Note about link parameter syntax: When the links to JPEG2000 images are part of an XML document, be sure to encode or "escape" any special characters within the linking URL. XML files will fail validation if they contain unescaped ampersands, apostrophes, quotes, or greater than/less than symbols. For instance: the ampersand symbol "&" in the IDS parameters syntax "width=1257&height=812" should be replaced with "&" so that the parameters read "width=1257&height=812". More about xml special characters escape sequences…

Linking to a static image

A 5025 x 3245 JPEG2000 image is deposited in the digital repository with the persistent identifier (URN) urn-3:HUL.OIS:jp2-sample. This URN, with no additional parameters, will resolve to a medium-sized JPEG:

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample 

By adding width and height parameters to the URN, you can control the dimensions of the static JPEG image. The table below illustrates this method:

Linking to the interactive viewer

To create a link that will deliver a JPEG image within a web-based interactive viewer, add the buttons=y parameter to the end of the persistent identifier.
http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?buttons=y

List of all JPEG2000 parameters

Below is a list of all JPEG2000 URL parameters available with the Image Delivery Service (IDS). Note the value in the View Type column, which indicates when a parameter is available with the interactive view, the static view, or both.

Parameter

Description

View Type

Example Use

buttons

The buttons parameter with any value enables interactive image presentation. A value of buttons=t puts the controls at the top; buttons=l, buttons=y, or any other value puts them at the left. Omitting the parameter displays the image without controls

Interactive

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?buttons=y

viewheight

The maximum height of the image pane in the interactive view. Values less than the implementation minimum (currently 50) will be interpreted as the minimum; values greater than the implementation maximum (currently 2400) are interpreted as the maximum. The default height is 600. This affects only the initial height; the user can change the size of the image pane.

Interactive

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?buttons=y&viewwidth=158&viewheight=102

viewwidth

The maximum width of the image pane in the interactive view. Values less than the implementation minimum (currently 50) will be interpreted as the minimum; values greater than the implementation maximum (currently 2400) are interpreted as the maximum. The default width is 800. This affects only the initial width; the user can change the size of the image pane.

Interactive

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?buttons=y&viewwidth=158&viewheight=102

rotation

This specifies the initial rotation of the image in the interactive view as well as the static view. The value must be 0, 90, 180, or 270.

Interactive and Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?buttons=y&rotation=90&viewwidth=158&viewheight=102

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?rotation=90&width=500&height=500

height

The maximum display height in the non-interactive view. Values less than the implementation minimum (currently 50) will be interpreted as the minimum; values greater than the implementation maximum (currently 2400) are interpreted as the maximum. The minimum is defined to avoid implementation problems with scaling to very small pixel dimensions; the maximum is based on policy. The default height is 768. The image will be displayed at the largest size within the height and width constraints while preserving the aspect ratio.

Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=315&height=203

width

The maximum display width in the static view. Values less than the implementation minimum (currently 50) will be interpreted as the minimum; values greater than the implementation maximum (currently 2400) are interpreted as the maximum. The default width is 1024.

Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=315&height=203

html

This parameter is new with this version of IDS. It applies only to the static view of JPEG2000 images. If this parameter has any non-empty value, such an image is presented as an HTML document containing only the image. If html is empty or absent, then the image is presented as a JPEG document.

Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=500&height=500&html=yes

s

Specifies zoom level. Acceptable values are anywhere between 0.1 and 4 (depending on the maximum image size) with 1=100% zoom level. This parameter works only in static view. The width and height parameters have to be present in conjunction with the s parameter in order for IDS to display the image correctly. The s parameter will also work in conjunction with width, height, x and y parameters. If at the specified zoom level the total size of the image is bigger than specified width and height, a slice of the image will be delivered (starting with top pixel and down to the specified width and height for the image). If x and y are used in conjunction with width and height then the same scenario will be true except that the view will start with a top pixel offset by x and y numbers of pixels.

Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=1000&height=1000&s=1

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=1000&height=1000&x=300&y=300&s=0.125

x

The offset x coordinate of the upper left corner of an image region. The width and height parameters have to be present in conjunction with the x and y parameters in order for IDS to display the image correctly

Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=1000&height=1000&x=300&y=300

y

The offset y coordinate of the upper left corner of an image region. The width and height parameters have to be present in conjunction with the x and y parameters in order for IDS to display the image correctly

Static

http://nrs.harvard.edu/urn-3:HUL.OIS:jp2-sample?width=1000&height=1000&x=300&y=300

sys

Specifies the invoking discovery application. This is a parameter for internal OIS use. It works in conjunction with OIS supported discovery systems.

Interactive (internal LtS use)

 

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