Field Reports for Raster Data: NOAA Charts
Previously on the blog, we’ve discussed the concept of field reports and groundtruthing on top of raster data (like satellite imagery), and the simplicity of accomplishing this in Fulcrum. Using Fulcrum’s native support for MBTiles-based map tile packs, any raster can be turned into a portable tilecache you can load onto mobile devices in Fulcrum, allowing you to annotate on top of the map using custom-designed forms.
I’m a recreational sailor, and have been working recently with NOAA’s electronic charts, thinking on ways to make the data more useful for mapping on mobile devices. One common issue when using the published navigation charts is that they can be out of date in certain ways — missing depth measurements, missing markers, or having incorrect feature markings. I built out a Fulcrum app for reporting these sorts of issues with the charts while out on the water, so over time while reading the charts, I can tag and report locations where there might be a channel marker missing, or a shallow sandy area that isn’t visible on the chart.
Taking my collected data and offline chart, I built a quick map to show the capability here. These few records I mapped show missing or deficient parts of the chart, giving me a simple and fast way to tag a spot while on the water, for submission later.
There are hundreds of use cases for this capability. You could load offline caches of aerial photos, review CAD site plans in the field, or dozens and dozens of other examples where field annotations are required. And because Fulcrum allows you to build apps to address several mapping requirements at once, my “Chart Errors” app just becomes one of several that I need for mapping different data while in the field.
If you have other ideas on where this might be useful, I’d love to chat. Ping me on Twitter with any questions!