since the historic voyage of columbus the science of mapmaking has played a leading role in the birth and development of america through the intervening centuries map information concerning this great country has grown with ever increasing rapid an mapmaking in the olden days was like painting a masterpiece a slow laborious and highly specialized task requiring the utmost skilled and patient mapmaking today has the speed of all modern streamlined methods but it is still a highly specialized occupation today the finest men formerly the prior possessions of the privileged few can be had for the asking presto and right at their fingertips modern motorists can have an information girl on any road they may wish to take but how many of us ever stop to think what a tremendous task it is to keep constant check on the millions of miles of roads in the united states the biggest catch in making road maps is keeping them up to date modern math makers of solve this by developing a trick method of printing revised maps can be put out every two weeks by this method maps can have their faces lifted without fuss or feathers here's how it's done every time a road is to be built or repaired symbols showing its progress are over printed on the latest edition of the regular road map the map companies all their time checking road reports and drawing in symbols indicating the latest road conditions these symbols are first gone on transparent sheets laid over the original master map from which all road maps of that district  this particular symbol for instance shows that certain roads are under construction but that the tours are provided this symbol will be drawn over every road that fits this classification at the time the map goes to press but wait a minute how does the draftsman know all this it's a cinch he can't walk every mile of every road the united states well somebody has to who is this fellow with the seven league boots this work is done by field men  travel the equivalent of many round trips to the moon as a rule these map detectives work in players one man driving the car at the other plots road changes on a special chart book notations are carefully checked against special instruments to ensure complete accuracy growing a straight line in a moving automobile on a bumpy road is one job it calls for a steady hand and a car that smoothly cooperates these road changes when carefully drawn to scale in the  are now ready for the big leagues the master detour maps in the drafting rooms here is another type of symbol often found on up today detour maps this one indicates road under construction but open to traffic in other words drive with care automobile club sculls like these also run down valuable road clues these men often do two jobs at once besides gathering data for the latest detour maps they also check new findings against old united states geological survey topic graphical sheets on the is they not only indicate the top august they have the land growing in all mountains canyons and rivers but they also check official mileage figures from point to point comparing them with those already listed on the survey sheets since many of these were drawn up from surveys made over thirty years ago some roads are found to be longer or shorter than their birth certificate shows being a rhodes scholar is no soft snap driving around death valley in the summer isn't found in the pink t section of the book but it's all in a day's work as far as these boys are concerned years spent in the wide open spaces of toughened them to take the worst old man weather off supply looks pretty slim one of the many things these auto club scouts keep tab on is the rise and fall of elevation at certain points since the earth's surface is constantly changing like the cost of a baking pie they often discover that what was lowdown on earlier surveys is now on the up and up elevations are recorded with an android a special alpha meter like those used on airplanes this android is so sensitive to atmospheric pressure  registers changes the elevation in inches this reading is then checked against the altitude figure on the geological survey benchmark these benchmarks found all over the united states list elevations for each locality if the road scouts elevation is at outs with a benchmark reading he makes a notation of the difference and send it to the geological survey headquarters in washington in the meantime there are many more roads to be covered so the boys better step on it or they will never make their deadline state highway departments and road construction companies also do their stuff and giving much valuable information for keeping maps up to date this particular simple road closed to traffic means just what it says when you come up to bad news like that there's only two things left to do get a tractor or turn back well here comes someone now is he going to be sore when he finds he has to go around by pumpkin highway official who in gathering data for their own use contribute much helpful information to the makers of road maps this grade ometer for example registers the pitch of the grade the car is resting on when recorded on the highway department survey map this data will be sent to map company draftsman along with blueprints of the road being built years it's well teamwork on the part of everyone that gets speedy accurate information from modern road maps daily these men sail into their jobs on mindful of grueling road in weather conditions scenes like these multiplied thousands of times are continually taking place throughout the length and breadth of america each man adds his piece to the ever growing an ever changing jigsaw puzzle that makes up a road map speed is essential for taking early in the case of detour maps speed in getting the news on a map while it's still news speed in revising it when the roads are again open to traffic when all this last minute road information has been transposed to the overlay sheet the sheet is removed and placed in a special vacuum frame a huge camera then photograph the overlay onto a glass negative this negative is photographically transfer on to a sensitized zinc plate which after having its face boxed in an acid solution is ready to be inked unlocked on the press this  standard road map these in turn are automatically cut been pulled into the proper size ready to give folks a good steer yes mapmaking has changed has kept pace with the changing america modern maps guide us over the modern road to the left over great super highways such as the famous new pennsylvania turn modern maps taken today's motorists where they want to go when they want to go quickly comfortably