![]() ![]() There is no notation of the actual unit type used on a RF scale. įor example, a RF scale of 1 : 1,200 means that every one unit on the map is equal to 1,200 units on the ground. Like verbal scale, representative fraction (RF) scale is also a text based scale but no units are shown.įor RF, scale is a simple ratio of map to ground measurement with a colon between the two measurements. ![]() Representative Fraction as a Scale on a Map This type of scale is sometimes confused with Representative Fraction scales. The left side of the verbal is the unit of measurement on the map and the right side of the ratio is the unit measurement on the ground.įor example the verbal scale, 1″ = 100′ means that one inch measured the the map represented 100 feet on the ground. Verbal Scale on a MapĪ verbal scale is text based, with the scale shown as a number and type of unit measurement equal to a specified unit measurement on the ground. The top scale shows the comparable ground measurement in kilometers (km) and the bottom bar scale shows the comparable length in miles. Please note if you are following this example on your PC the Map View Zoom requirement may well differ from this example due to different monitor resolutions.Bar scale showing graphically the ratio of map units to ground units. I can now drag the map using the mouse to line up exactly the area of mapping I wish to print. The black outline in the above screenshot is showing the area of mapping that I can print of Ordnance Survey 1:25,000 mapping at scale to my printer. If I then alter my Map View Zoom and zoom out, I now have more mapping on screen, and I can now see the print area. If we count the map grid squares, we can see that on my monitor I can view approximately 5km * 3.5km which is less than the 7.25km*5km we are able to print. It does’t show me what mapping will in fact be printed. If on my computer, I open up OMN, select OS 1:25,000 mapping on screen, and press the print button, then the below screenshot is not very informative. These two zooms are therefore independent of each other.Ī worked example based on the calculation above: This alters the scale at which a map print will be made. Print Zoom – On the Print Map window is a drop down combo box called Zoom. It does not alter the amount or scale of what is being printed. This simply alters the amount of mapping being displayed on your screen. Map View Zoom – This is simply how you normally zoom maps on screen when not printing. The OMN printing interface is very powerful, but involves control of two zooms: How to control printing maps through Outdoor Map Navigator ![]() ![]() So, to fill the paper available with mapping at the correct scale we need an area of mapping 7.25km by 5km. If we are printing Ordnance Survey 1:25,000 mapping, we now know how much mapping we are going to print:Ģ90mm = 29cm. To make the maths easy, let’s say the printer can only print on 290mm by 200mm. Although your printer may have A4 paper loaded in it, it most likely can’t print to the absolute edge of the paper.Ī4 paper is 297mm * 210mm. Printing a map – Because scale is important, one of the first things we have to do is communicate with the printer to find out how much paper we can print on. The amount of information to be printed is already decided. So we just take the photo, the user decides how large they want the image – say 6”*4”, and we send it to the printer. Printing a photo – There is no scale involved. If you can now imagine the squares on the page being smaller which would represent a higher DPI, and you could improve your circle. In simple terms, if you remember trying to draw a circle in your school maths book by shading squares you probably remember it not being very circular. Using more dots can improve the image quality through smoothing of edges. The higher the DPI of the printer, the more dots can be used to create the image. So, if a lake on the map is 2cm long, then in real life it is 2cm*25,000 = 50,000 cm = 500m long.ĭots Per Inch (DPI) – Printers produce images through a series of dots of ink. This simply means that if you measure something on the map, and multiply that answer by 25,000, you will have its length in the real world. Map Scale – Ordnance Survey Explorer maps are 1:25,000 scale. This difference in approach is all due to the scale of the map. It’s not obvious, but printing a photo from your computer is almost the logical opposite process technically of printing a map. Modified on: Wed, 23 Aug, 2017 at 3:17 PM Solution home General Printing Printing - Scale Printing Explained ![]()
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