Support & Contact

Version 3.0.2 supports Washington, California, Oregon, Texas, and Utah. Each state uses its DOT's official Linear Referencing System for milepost data. Additional states are planned for future releases.

Milepost data comes directly from each state DOT's official Linear Referencing System (LRS), providing sub-foot accuracy for milepost location.

Elevation profiles use USGS 3DEP LiDAR data (1-meter resolution) via the National Map. This is suitable for planning and reconnaissance purposes but is not survey-grade. Cross-sections and profile exports include a disclaimer noting this limitation.

Pin Mode allows you to drop a pin anywhere on Google Maps to retrieve milepost data. Click the green pin button to activate it, then right-click on the map and select "Drop pin here" or click directly to place a pin.

Some highway segments have "equation points" where the milepost numbering resets or overlaps due to historical realignments. "Back" indicates the segment before the equation point, while "Ahead" indicates after.

The Street View HUD displays when you enter Street View on Google Maps within any supported state. It shows real-time Route, Milepost, Direction, and Station as you navigate.

Composite Sheets are engineering-style 11×17 PDF exports that combine profile views, cross-sections, plan views with aerial imagery, feature annotations, and roadway data tables into a single sheet. These are designed for planning and reconnaissance use.

You can export elevation data as CSV (spreadsheet-compatible) or generate engineering-style PDF sheets for profiles, cross-sections, plan views, and composite sheets.

SnagMP Extension is currently in open beta — all features are available at no cost. Core milepost lookup and search will remain free permanently. State government employees receive complimentary Basic access through a verified email process.

The Extension is designed for desktop versions of Google Chrome and Microsoft Edge. Mobile browsers do not support Chrome extensions. For mobile use, see SnagMP Field below.

SnagMP connects to public government APIs (Census Bureau, WSDOT, Caltrans, ODOT, TxDOT, UDOT, USGS) to retrieve geographic data. These permissions allow the extension to make those requests directly. No personal data is collected or transmitted.

SnagMP Field is a GPS-based milepost locator built for highway fieldwork. It runs as a Progressive Web App (PWA) on your phone and works completely offline after a one-time data download.

SnagMP Field supports Washington, California, Oregon, Texas, and Utah — the same states as the Chrome Extension.

Visit the Field app URL in Chrome or Safari on your phone and tap "Add to Home Screen." It installs like a regular app — no app store needed. Then open Settings within the app and download your state's route data.

Yes. After downloading the route data for your state (a one-time download of ~15–25 MB), SnagMP Field works entirely offline using your phone's GPS. It's designed for remote highway locations with no connectivity.

Station Mode lets you set a reference point at your current milepost and then tracks your station value in real time as you walk or drive. This is useful for tying project stationing to mileposts in the field.

Supplemental datasets (such as Fish Passage Culverts) can be downloaded within the app. When active, you see a proximity-sorted list of nearby features with distance, stream name, and barrier status. Features also appear on the map view.

SnagMP Field is currently available at no cost.