Some time ago I posted some instructions on how to create on-line topo maps of hikes / excursions, starting from GPX files. Joseph Elfelt of Gmap4 has recently written to me, announcing the availability of new, and much improved maps. I checked the new maps out, and the quality and detail is simply stunning!
To get a map, you must first upload the GPX file somewhere (Google Sites works well). Once you have an URL for your GPX file, such as
then you can generate a high-resolution topographical map of the GPX trail by creating the URL as follows:
The “t=t4” parameter above selects new very high-definition topographical maps that are simply stunning to look at — better than any other ones I have seen.
If you use and appreciate the service, Joseph tells me that he would appreciate donations, to help with the cost of hosting and serving map quads (I should add that I have no relation to him, except of being a very happy user of his maps).
This is what Joseph wrote about how these new maps were created (reproduced with permission):
The person behind CalTopo.com is Matt Jacobs and his site is running the ‘civilian’ version of a map tool that he originally wrote to support wilderness search and rescue (SAR) activity. Matt’s desire for the highest quality topographic maps coincided with a massive project by the U.S. Geological Survey to make very high quality scans (660 pixels per inch) of all the topographic maps they had previously published. These scans are online as ordinary PDF files, they are not the new GeoPDF file format.
A vast amount of work was done by Matt to invent a system that would process those new very high quality USGS scans into map ‘tiles’ suitable for display by software (like Gmap4) which uses the Google Maps API (Application Program Interface). These newly created map tiles are hosted on the Amazon servers. There are some blog posts on Matt’s website that provide some insight into the processing steps needed in order to convert the USGS scans into high quality map tiles.
In late 2011 Matt contacted me and inquired if I would like to display his tiles with Gmap4. Since the scan quality of these map tiles is significantly better than anything else available and the tiles do not have any watermarks or ads, I quickly agreed. You can compare these map tiles (t4 Topo High) and the user-selected amount of hill shading (Menu ==> Hill shading) to any other online topographic maps and decide for yourself which maps look best.
Ultimately whether or not Gmap4 can continue to display these watermark-free state-of-the-art adjustable-hill-shading topographic maps will be up to you along with the other Gmap4 users. If you enjoy using Gmap4 and Matt’s best-of-their-kind maps, please consider making a donation that I can share with Matt.
Kudos to Matt and Joseph for making such great maps available to us all!