Welcome to Part 2! If you didn’t read Part 1, click here. On to drawing a sketch map.
Once you have all of your measurements it’s time to sketch them out on graph paper. One of the most difficult decisions to make is where to put the datum and what scale to use so that the entire site fits on the map. It can be a bit frustrating but you’ll learn over time how to do it with fewer mistakes. You’ll need some special skills for putting the points on the map too. You might also want a clear protractor or a round, 360 degree, translucent scale with a straight ruler attached to the center point. I have an engineering scale to use for distance. Keep in mind that the squares on the graph paper are not going to work for scaling your drawing. The scale will be determined by what ever method you choose and whatever fits best. I find which scale on my 6-sided engineering scale works best for the site and then draw my scale on the page to fit that measurement.
Put the points on the map in the order that you took them. Draw the datum point first. Then measure the number of paces that match your scale to the North and draw a point. Next, find the next bearing and measure the appropriate distance. When all the boundary points are done, draw in your boundary. Next, graphically draw in your features and artifacts. By graphically, I mean draw the center point and then illustrate the feature around it (WARNING: you may need to learn to draw what you see around you!). The last thing I draw on a sketch map are the landforms, prominent vegetation (i.e. trees and other significant natural features), rock outcrops, stream beds, and whatever else makes sense. The last thing, and sometimes the most difficult thing, that I draw are the topographic lines. Some people have a difficult time representing hills, ridges, and drainages topographically. This just takes practice. Look at a topo map while you are out in the field. Understand what you are seeing on the map and apply it to the landscape around you. Sometimes, while out on survey, I try to visualize drainages, mountains, and ridges as though they had topo lines on them. Try it sometime.
The level of detail in the finishing touches on your map will likely be determined by how anxious your crew chief is to get out of there and on to the next site. At a minimum you will need a north arrow, a scale, a data block, and a legend. The north arrow, for some people, is like a signature. I’ve seen all sorts. Some people like to design fancy ones and some use just a generic arrow. Make it your own. The scale is based on the scale of your map. Again, I’ve seen everything from fancy and detailed to generic. Do what you think best fits the site and your company. The data block contains all the site information. At a minimum it usually contains the site number, the date, the company name, the words “site sketch map” or something equivalent, the datum coordinates, your name, and the date. The legend should contain every symbol that’s on the map. If you put it on the map then put it in the legend.
The last thing you need to do is pretty simple. Take your map off your clipboard, fold it up, and put it in your pocket because many companies simply aren’t drawing paper sketch maps anymore and this was all in your head. Go back to sleep.
Still drawing sketch maps on paper? Send me some of your favorite creations (blocking out location data, of course) and I’ll put a collection of them up here. I worked with a person a few years ago that didn’t draw sketch maps: he drew works of art. They were absolutely amazing and had amazing detail. It didn’t take him all day either. Decades of field work had honed his skills and he was quick and efficient.
Send me your thoughts on this topic. I’d like to know if there are large companies that are still taking the time to do a quality sketch map or if it’s just the ones that don’t want to pay thousands of dollars for a good GPS.
Keep sketching...I”ll see you in the field.