OK, rather than trying to genericize my question, let me just jump to the chase. I’m organizing a Bike to School Day at my school. I want to create a map, centered on the school, with colored zones on it: So, for instance, if you live in the green zone, it’ll take approximately 10 minutes or less to bike to school; if you live in the blue zone, 20 minutes, and so on. The data exists in Google Maps, as it can tell you biking directions from one point to another, with estimated times, but it’s not in the format I want. Ideally, is there a way to get Google (or something like it) to just directly create the map I want?
And if I can’t do it directly, then what’s the easiest way to do it by hand? I don’t want to assume that the zones will just be circles, because the routes only follow roads, which don’t usually run in the ideal directions. In particular, the school is right next to a canyon, that only has a few bridges over it, so they won’t even be approximately circles: A student who lives a half-mile due west of the school would need a total route of over two miles, for instance, to get over the nearest bridge. I’m thinking of just trial-and-erroring a bunch of points along likely routes and drawing a polygon around those points, but is there a better way?
And even once I’ve decided on my zones, is there an easy way to do the drawing itself? The zone colorings must, of course, be translucent, so the map can be seen through them. I know that’d be easy to do via layers in a program like Photoshop, but I don’t have access to any such programs.
I don’t know how to automate what you want to do, but I’ll mention that Google’s My Maps allows you to draw lines and shapes on top of a map, if you don’t find a better way.
Hm, thanks, @Stranger_On_A_Train , that looks like exactly what I’m looking for! It looks like I’d need an account, but there’s a free trial available, and I’ll only need the one map (and I’ll just have to make sure to save it for next year).
Unless you find a better method, you can use PowerPoint. When you have your Google map on your monitor, do a screen capture, then paste into a PowerPoint slide. You can crop the image to get rid of the window edges and browser title bars. Now you can draw anything you want on top of your map. Anything you draw in PowerPoint and any image you import into PowerPoint can be rendered anywhere from 0% to 100% transparent. So leave your map as fully opaque, and draw your travel time boundaries using transparent lines, and/or polygons.
Note also that if you import graphics into PowerPoint that have just a few colors, for example a black and white line drawing, you can tell the PowerPoint to choose one of the colors in that graphic to be rendered as fully transparent. This is really useful when you want to import a line drawing, and have items behind it in your PowerPoint slide show through.
The kind of map you want is called an isochrone map. Openrouteservice has a tool for building such maps. It’s free and no registration is required. Visit OpenRouteService route planner - directions, isochrones and places and make your selections. From the top down in the left-hand pane, you want to choose profile: bike. Then make sure Reach is selected and not “find and go”. Then under Find a place, enter the address of the school. Then under Parameters, choose isochrone method: time. Then under Range choose 30 minutes (which seems to be the maximum). Then under interval, choose 10 minutes or whatever other period is convenient. You should see a message in the upper right corner saying Isochrones ready. Unfortunately, it does not always recenter the map for you, so you may have to zoom and pan to get where you want to be.
And thank you, too, @bibliophage , that looks a lot easier than signing up for ArcGIS. I would ideally have liked contours out to 40 or 50 minutes, but it looks like I can approximate that asking it for 8-minute contours on an e-bike rather than 10-minute contours on a regular bike.
This website also creates isochrone maps, and is pretty intuitive. I don’t know what extra features you get if you pay for it, but the free demo seems to allow for an unlimited number of maps from a fixed location.