Maps/Mileages/Elevation Gains and Losses
How I Calculated Them Over the Decades
Back in the early 1980’s I purchased a Silva Map Measuring tool. It had a very small gear wheel that you would roll along the trail on a map. As the wheel turned it was geared to another wheel that was calibrated to different map scales, which would tell the distance between two points. Using this I would get the data for the trail distance and note the elevation at “nodes” at the ends of the measured legs.
To get a measure of the distance travelled as well as the elevation gain, I wrote a simple basic program that computed the difference in elevation and the distance between the ends of each measured leg along with the the cumulative distance and elevation gain and loss from the start. This was a tedious process but gave useful results.
In the 1990’s you could buy Topo Maps on CD and the associated software allowed you to draw tracks and routes and make a printable map. These also provided means to transfer the data to GPS handsets which could be used in the field. I modified my program to use these data files to give me similar but more accurate results compared to those of my earlier manual measurements on physical topographic maps. In order to account for the variable up and downs you encounter along a trail, I came up with a factor of 20 feet or up/down per mile
I had purchased topo maps on CD’s from several different publishers, but eventually settled MapTech Terrain Navigator software. After several updates the software provided a tie in to Google Earth so that any track or route you made on the topo map could then be displayed simultaneously on Maptech and Google Earth. This worked well for many years until the current versions of Google Earth could no longer be recognized by the MapTech program.
I tried many online versions of mapping programs with varying degrees of success. These included Acme Mapper 2.0, Hillmap.com, and Caltopo. Each had their advantages but several years ago Google changed their conditions for using their satellite maps and the free online mappers could not provide high resolution satellite images on a free basis. Eventually I suscribed to Caltopo, which includes the use of Google Satellite Maps as well as several different types of topographic maps. I am well pleased with the service.
The links I provide to Caltopo for the maps in my albums will show a Forest Service topographic map. If you are a Caltopo suscriber, you can quickly switch from the topo map to a satellite map with the click of a mouse. For hiking in the high country, satellite maps are very useful because you can often see the trail clearly and can draw your route directly on the satellite map and then switch it to a topo view.
One thing rapidly becomes apparent when you follow a trail on the satellite map – it bears little resemblance to the trail that is shown on the topo maps. On the other hand, the satellite maps are not useful when the trail goes through heavilly forested terrain. In that case you have to rely on the trail locations as given on the topo maps.
Today (2023) I use Caltopo to create a track or route following the trail as closely as possible, using satellite maps whenever possible. I then export that track/route from Caltopo as either a gpx or Google kml format file. Using the freeware POIConverter program I can convert the Caltopo gpx/kml file to the MapTech “RXF” file format that Terrain Navigator uses. I use these “RXF” files with my BASIC program to get distances and elevation gains/losses.
When I provide a Map in my photo albums, if I have used Caltopo, I will provide a link to the Caltopo map. Unfortunately, if you do not have a subscription, you will not be able to render the route using Satellite map but are limited a less precise alternative, Global Imagery. If you want to make the effort, you can, however, export the Caltopo route to a Google “kml” file which can then be displayed in Google Earth.
-Cascade Bill Mooseker
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