Let's say you want to create a large Google Maps poster of the Charles River in Boston/Cambridge, the Tideway on the Thames, or the San Francisco Bay and display the many different rowing routes and relevant information (distances, docks, bridges, boat houses, buoys, obstacles, pubs, etc). These instructions might help you.
Caveats: Google may change their applications/limitations at any time to render these instructions moot, useless or something else completely. These instructions may also depend on a particular web browser version. This is a kludge and subject to all the problems of that kind of solution.
Google is Great...
Google Maps and some of the subsequent mashups like Gmaps Pedometer and MapMyRide are extremely useful in creating and sharing map information. You can do some amazing things with these map tools. Throw in Google Earth and you have incredible resources at your disposal.
The more complex your Google map gets, the more likely you are to run into some of Google Maps limitations for display and printing. You may create a map with many routes and other information on it, or one long route comprised of many points and other information, but not all of it is displayed on one screen. A typical manifestation of this problem, especially if you import information (e.g., KML files), is the "paging problem."
Map is Split into Several Pages
Last year, I compiled GPS data from a variety of sources into a comprehensive map of the trails in the Ashland (Oregon) watershed. The number of pieces of information exceeded some Google maps limit (apparently the 1000 "features" limit, but possibly another). The result was a map that displayed over several pages. Any one page displayed some information (trails, in this case) of the map, but not all. You had to page through (see bottom of graphic below) to get a sense of the whole map. It's as if the map had several layers, but you could never display all of them at once. And, any screen print would display only what was on the screen at that moment. This kind of behavior is unacceptable if the goal is to create a printable map displaying all the relevant information.
Before you get started...
- These instructions assume you have already created and/or imported your routes, trails, etc into a Google Map. This post doesn't address how to create Google maps themselves, but Google provides simple instructions for creating one here. Alternatively, you can use Google Earth to create routes and export them as KML files. Or you can use your GPS and export KML files and then import these into Google Maps. There are many ways...
- If you intend to print your results using these instructions, you will first need to download Firefox (that's a US link) if you don't have it already and install the add-on ScreenGrab (look for at addons.mozilla.com).
1. Open your Google map. All trails/routes and other information must be in a single map. This may cause paging (e.g., different trails/routes appear on different pages of this map and therefore can’t all be viewed at the same time). The first few steps will address a way around the paging problem. If you don't have the paging problem, you can jump to step 4 to learn how to create a large format map file suitable for printing.
2. View the last page of the map file by advancing to the last page. It doesn’t matter that all the trails are not depicted in this view. Then right-click on the "View in Google Earth Link" and select "Copy Link Address". NOTE: you're not actually going to do anything with Google Earth here.
3. Paste the copied link into the Search Maps field in FireFox and click Search Maps.
This may result in some ugly data showing up in the attribute fields (ignore!), but not in the map itself. You should notice that all of your map data is now displayed in one page. It may not look particularly pretty, but you've gotten rid of the paging problem! Now, on to preparing your map for printing.
4. Now, choose the view: generally Satellite or Terrain are best. Terrain has some advantages (shows contour lines), but will only allow just so much zoom (which is relevant to the next step).
5. View the map with all the trails in the most zoomed in Terrain view OR whatever zoom level you want for the Satellite map.
6. Click on the Link link and in the resulting window, select the Customize and preview embedded map.
7. In the resulting window, select Custom and then enter the size of your desired image (see below). In my case, I entered 3400 by 4200 (presumably pixels). This can take a long while to load (depending on the size of your map and your internet connection). You will need to adjust the visible map for your output needs. Here are some tips:
- Use the plus and minus buttons to zoom in and out, respectively. I recommend zooming in to the maximum, particularly if you are using Terrain View. The results will be 72 dpi whatever you do (this will be a screen snap shot, so that is the resolution you get).
- The information you display appears to be the upper-left corner of your eventual map, so you may have to experiment to see if you are capturing what you want. In reality, this probably means completing steps 8 and 9 and then iterating from step 6 on.
8. Click on the ScreenGrab icon in the lower-right section of your FireFox browser screen. (If you don’t see the icon, make sure you have “View->Status Bar” on.) Then select Save->Complete Page/Frame.
This simple step captures all your map data (assuming you entered the dimensions correctly in step 7). It's as if your screen extended to the dimensions you gave in step 7 and then ScreenGrab took a snapshot of that. Pretty nifty!
9. Save the resulting file (as map.jpg or similar) and open in Photoshop or equivalent. Make sure you captured what you wanted or repeat steps 6 through 9 until you do.
10. Transfer (e.g., with a thumb drive) or email the file to a printer with the requisite sized printer. I have had good luck with Kinko's, but I am sure there are many printers who can print your file.
NOTE: The spirit of these instructions is to enable you to create a personal use map, not a commercial product; Google has some specific use restrictions if this is your intention.
NOTE: The Ashland trails map information I gathered and entered laboriously, tediously, ad seemingly freakin' infinitum, I subsequently sent to a GIS specialist. She took my data, enhanced it, used LIDAR to reroute some proposed trails and produced--in significantly less time--a superior map now available for the Ashland Trails Master Plan. In other words, if you have professional needs, you may want to seek out a professional!