![]() If possible, it is best to avoid these formats, instead using. These document types are often also the most difficult to remediate, as they need to include a logical reading order, alternative texts for any images or figures, and appropriate tagging of document elements and tables. PDFs and Word documents are the most common data release documents to be flagged for being non-compliant with Section 508. Examples include EXIF Tool ( ) and XnView MP ( ). There are several free tools available for helping users edit EXIF metadata, including some batch editing capabilities. In EXIF, for example, ImageDescription would be an appropriate field in which to place alternative text. 3).ĭetails tab in the properties of a jpg image, focusing on the title and subject fieldsįor Mac users, a control-click and navigating to ‘Get Info’ (or pressing command-I) should lead to a similar screen.įor adding alternative text to a large batch of image files where the alternative text may only need to differ in small ways (e.g., site name), the SBDR team can share Python scripts, created by the Geology, Geophysics, and Geochemistry Science Center’s data managers, with you to help you get started.įinally, imagery headers (e.g., EXIF, or exchangeable image file format) can be an option for embedding metadata into an image. Here, you can add a title and descriptive text in the ‘title’ and ‘subject’ fields (fig. For PC users, this means right-clicking on the image within the file explorer, going to ‘Properties’, and then ‘Details’. If data authors only need to add alternative text for a few images, it can be easiest to edit the file directly. Whenever possible, images released through a data release should be in an open format (PNG, TIFF, JPG, etc.), with alternative text for each image embedded within the image’s metadata. For example, avoid merged cells, as it can be difficult to understand how these cells fit into the data structure without visual cues.Įmbed alternative text in open image formats Verify that the data structure and any data tables are in a logical reading order and do not require visual aids to understand. Use descriptive file names that convey what is within the document (e.g., avoid non-descriptive names like “Table 1” or “Bird Data”) Below are a few considerations for making sure your machine-readable formats are fully accessible:Įnsure that spreadsheets do not rely on colors or other visual elements to convey meaning that the text does not convey, Machine-readable formats are generally able to be accessed by screen readers, and thus fulfill accessibility requirements. Using open, machine-readable formats, (CSV, TXT, ASCII, XML, JSON, etc.) often means automatic compliance with section 508. Whenever possible, use open, machine-readable formats A few quick tips are outlined below. Note that ScienceBase will flag non-compliant documents as best we can, but ultimately, it is up to data authors and the internal review process to ensure that data and related documents are compliant. The ScienceBase Data Release (SBDR) team has compiled some resources and answers for data authors, in coordination with the Science Publishing Network (SPN), and helpful USGS data managers and center staff. ![]() While Section 508 compliance has been a major topic of discussion for USGS staff who manage websites and prepare reports for publication, it can often be unclear to data authors what exactly they need to do to make their data release compliant with Section 508. JPEG Lossless question.Section 508 is federal policy under the Rehabilitation Act, and requires the USGS “to ensure any information and communication technology (ICT) it develops, procures, uses, or maintains is accessible to both Federal employees and members of the public with disabilities” ( USGS Survey Manual 600.6).With the majority of internet users on high-speed connections today, Progressive JPEG is rarely used. ![]() It doesn't make the image download any faster, but it can give the illusion of speed since the blocky image loads right away on a slow connection. ![]() ![]() It's your best choice for JPEG files today.Ĭreates a JPEG file that displays as it downloads, starting blocky, and getting progressively clearer as it downloads. All modern browsers support it, but earlier ones didn't. This JPEG format option provides an optimized color and slightly better compression. Wrote:The three types of JPEG are Baseline, Baseline Optimized, and Progressive.Īll web browsers recognize this JPEG format. ![]()
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