Tuesday, March 11, 2014


I love them. I would as soon sit and pore over a map or chart as much as watch TV, probably more. Cartography, both subjectively and literally, is an actual art form. They stir the imagination, and only hint at what could be explored if one could just get out on the water.

But, first things first. You’ll frequently (way too frequently) hear the words map and chart being used interchangeably. They are no more the same thing than a Corvette and a Dodge Ram diesel pickup. They may be similar in some respects, but each, map or chart, has its own distinct function. It has nothing to do with quality, as there are good and bad grades in each. First, a map.

Maps of the Upper Mississippi River
A map is a graphic or symbolic representation of a section of the earth’s surface. Note the distinction between graphic and symbolic. The map is probably the broadest classification, but is a subset of navigational maps, which are a subset of navigational charts. Maps basically function to get one from Points A to B, and to simplify what actually exists for easier viewing. They may or may not be to scale, and may be adapted or slanted for special applications, like hiking maps, biking maps, topographic maps, railroad maps, survey maps, highway maps, military maps, flood zone maps, pipeline maps, fault line maps, geological mineral or mine maps, tax assessor maps, and much more. About the most involved addition to a map will be the addition of contour lines to connect points of equal value, like altitude, temperature, wetness, tree line, etc. Maps are usually not particularly concerned with graphic distortion, mostly because they usually cover relatively smaller areas. Graphic distortion is not as important as relationship, and even some of those are intentionally distorted for ease of use. For example, if true graphic representation was used, small streams, creeks, or even small rivers would be too small to be printed on a map, let alone seen. Therefore, they may be inaccurately enlarged for those interested in waterways so they can be easily found and followed. The distortion may be enlarged even further so things like rapids, falls, dams, and portages may be shown. Another example of deliberate distortion is to remove some things that actually exist so there is more room on the map to emphasize just those things of interest to the user of that particular map. This is called “decluttering.”

When selecting a map, is it important that it be to scale? If it is, then it may be important to properly interpret the scale being used. The greatest confusion comes from scale and geographic area being inverse proportions. Large scale maps cover small areas, and small scale maps cover large areas, and are shown as a ratio. A classroom map of an entire nation may be 1:10,000,000, a highway map may be 1:1,000,000 to as large as 1:250,000, but a hiking map may be only 1:25,000. As a guideline, if you want a lot of detail, one may want a scale of 1:50,000, but you will need a lot of maps to cover the route. If the area is not all that complicated or involved, a 1:250,000 scale map may serve, or serve as a trip guide or study guide until you reach a problem area. The solution then is to use a small scale map, and back it up with a few larger scale maps for areas of particular concern.

Where do you find maps? There are dozens of sources. Some, like U.S. Geological Survey, are the official government maps with no frills, just good, reliable, and most frequently updated topographic maps. The plus here is that they are both to scale, and further, they are oriented to the cardinal points (NORTH, and maybe also East, South, and West) Start by getting familiar with their website at:

Or call 888-275-8747 (888-ASK-USGS). A couple of basic definitions will help guide you along. One mile = 1 minute of latitude. Therefore, just as in time where 60 minutes equals an hour, in arc, 60 minutes is equal to one degree. So, when you find a 7.5 X 15 minute map, you are looking at an area roughly 7 1/2 miles by 15 miles, or a scale of 1:24,000. A 30 X 60 minute map will cover an area 30 by 60 miles, or a scale of 1:100,000.

Canadian maps may be found at:

This gives you an atlas of available maps. Then, obtain a directory of U.S. or Canadian dealers or printers where maps may be obtained. For questions, they may be reached at (800)661-2638 or (819)564-4857.

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