CAD Drawing / GIS Map

Who Is Affected

Blind users who rely on screen readers, users with severe low vision who cannot interpret complex visual diagrams, and users with cognitive disabilities who need text-based information to understand spatial relationships.

What This Means

CAD drawings, GIS maps, survey plats, and similar technical diagrams contain critical information that is completely inaccessible to screen readers. When a blind resident encounters a zoning map or utility diagram, their assistive technology reads nothing — creating a barrier to accessing government services and information.

These documents require either detailed alternative text descriptions or structured data tables that convey the same information in a text format. The complexity of the remediation depends on the document's purpose and the level of detail citizens need to understand.

Fix: Document

The remediation approach depends on the document's intended use and complexity:

For Simple Reference Maps (2-3 hours)

If the map shows basic zones, districts, or service areas:

1. Add comprehensive alt text describing the map's purpose, key features, and boundaries.
   • Example: "Zoning map of downtown Springfield showing Commercial (pink), Residential (yellow), and Industrial (blue) districts. Main Street forms the northern boundary between Commercial and Residential zones."
2. Include a text legend listing all symbols, colors, and their meanings.
3. Add contact information for users who need specific details about their property or location.

For Complex Technical Drawings (4-8 hours)

If the document contains detailed measurements, coordinates, or multiple data layers:

1. Create a structured data table with columns for:
   • Location/Address
   • Zone/Classification
   • Relevant measurements or coordinates
   • Any restrictions or special conditions
2. Add section headings to organize different types of information (e.g., "Parcel Information," "Utility Lines," "Elevation Data").
3. Provide both summary alt text and detailed table — the alt text gives the overview, the table provides specifics.
4. Include a "How to Read This Document" section explaining the technical terms and abbreviations used.

For Interactive Web Maps

1. Provide a text-based search interface allowing users to enter addresses or parcel numbers.
2. Create summary pages for each zone or district with key information in HTML format.
3. Offer alternative contact methods (phone, email) for users who need personal assistance interpreting the map.

Quality Check Steps

1. Use a screen reader (NVDA is free) to test the document from start to finish.
2. Verify that all critical information from the visual map is available in text form.
3. Test with the document zoomed to 200% to ensure text remains readable.
4. Confirm that color is not the only way information is conveyed.

Standard Reference

WCAG 2.1 Success Criterion 1.1.1 — Non-text Content, Level A

All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except when the non-text content is a test or exercise that would be invalid if presented in text, or is primarily intended to create a specific sensory experience.

• W3C Understanding SC 1.1.1
• WCAG Technique G92 — Providing long description for non-text content
• WCAG Technique G73 — Providing long description in another location
• WCAG Technique G74 — Providing long description in text near non-text content
• WCAG Failure F65 — Missing alt text for images
• WCAG Failure F38 — Not marking up decorative images