Although this blog is predominantly focused on my music
and DJ’ing career, I also want to share some information about my other
career: Canadian Reforestation.
The information in this post is part of a training series
from the Replant.ca website. More
information can be found at this link:
I’ll put the text and audio download link from this
training module below, but let’s start with the YouTube video for the module:
Section 07 - “Map Reading”
In this section we'll
learn a few basics about Map Reading.
We'll also talk about how to understand map directions, coordinate
systems, topography, contour lines, scales, and geo-referenced digital maps.
All planters should have a
basic understanding of maps and cartography.
One of the benefits of becoming a tree planter is that you'll learn a
lot about the world around you, including things like being able to tell
directions without a compass.
Let's start with the very
basics. On most maps, all the writing is
oriented the same way, so you can determine a "top" and a
"bottom" to the map. If the
map doesn't indicate otherwise, the top of the map is always north. This is the case in probably 99% of
maps. Occasionally, for some odd reason,
north will face a different direction, but if it does, there should be a little
compass rose symbol or arrow on the map that points to north.
GPS System
Most maps that planters
use in British Columbia will also have coordinates on them. There are literally thousands of different
coordinate systems in place throughout the world. Some of them were created centuries ago by
early explorers and surveyors, and it's safe to say that most are extremely
confusing. Within BC, you'll normally
just encounter one of the most well-known systems used today, a traditional
Latitude and Longitude system. The
Latitude and Longitude coordinates will be in "northings" and
"westings" when you refer to coordinates within British Columbia.
Northings, or the distance
north of the equator, range from about 49 degrees at the bottom of BC to about
60 degrees at the top of the province.
These are also known as the latitude.
Westings range from approximately 114 to 140 degrees, with the lower numbers
on the east side bordering Alberta.
These are known as the longitude.
If you have problems with respect to latitude and longitude in terms of
remembering which is which, think of the word "flatitude" instead of
latitude. Latitude lines are flat lines,
rather than vertical, when you look at a map.
If you're ever using software or a GIS system that doesn't allow you to
type in the letters N or W to represent northing and westing, use positive
numbers for the northings, and use a negative sign for the westings. The number representing the latitude always
comes first, before the number for the longitude.
If you get a block map,
sometimes it will display the coordinates on the sides of the map, in a
scale. As mentioned, the latitude is the
distance above or below the equator, hence the reason why latitudes are always
"north" in British Columbia.
That's why the latitudes run up and down the sides of a map, even though
a line of latitude is flat, running from left to right on a normal map. The longitude is the distance to the east or
west of the Prime Meridian that runs north/south down through England, hence
why longitudes are always "west" in British Columbia. That's why lines of longitude are vertical,
and the longitude numbers always run along the bottom or top of a map.
In addition to the
possibility of seeing latitudes and longitudes listed on the sides of your map,
there may be a single point coordinate (latitude and longitude) listed
somewhere in the map's key. That is
probably for a point in the very center of the map, although occasionally, it
will refer to a random point somewhere on the map where a surveyor decided to
pick what's known as a "tie point" to start plots or something
similar.
The Global Positioning
Satellite system, also known as GPS, is a network of approximately thirty
satellites that are operated by the US government. If you're at any point on Earth with a GPS
device that can "see" three satellites, you'll be able to determine
your exact position in terms of latitude and longitude. Add a fourth satellite, and you should also
be able to get your elevation above sea level.
That's a simplification, but good enough for our purposes.
The GPS system (also known
as NAVSTAR) is the American variety of GNSS, or Global Navigation Satellite
System. Russia has a GNSS called
GLONASS. Other political entities
(Japan, China, India, and the EU) are also in the process of deploying their
own GNSS systems.
GPS coordinates are
typically listed in degrees, minutes, and seconds. These refer to units of arc, or distance on
the surface of the Earth. An arc-degree
covers a very large amount of distance.
The exact distance depends on where you're located on Earth, but an
arc-degree can sometimes be as large as 65 kilometers or more. An arc-minute is smaller, maybe around a
kilometer wide depending on your location. An arc-second is a pretty narrow range, only
maybe around twenty to thirty meters wide, although again, this distance
depends on your exact location. There
are sixty arc-seconds in an arc-minute, and sixty arc-minutes in an arc-degree,
just like in time-keeping. There are 360
arc-degrees to cover the entire surface of the Earth, just like there are 360
degrees in a circle. A lot of the time,
people drop the "arc" prefix when they're talking about GPS
coordinates, and just use the terms degrees, minutes, and seconds.
Sometimes, the written
format of a GPS coordinate is written using specific symbols for degrees,
minutes, and seconds. Degrees are
symbolized by a small superscripted circle.
Minutes are symbolized by an apostrophe.
Seconds are symbolized by a quotation mark symbol. So for example, 54 degrees, 36 minutes, and
30 seconds would be listed as 54o 36' 30". At other times, decimal points will be used
for either just the seconds, or sometimes for the minutes and seconds. In this example, if just the seconds were
converted to decimal, the reading would be 54o 36.5'. That's because thirty seconds is 0.5 (or
30/60) of a minute. If the minutes were
also converted to decimal, the reading would be 54.65o. That's because 36 minutes is 0.6 (or 36/60)
of a degree. If you have a GPS device,
you can go into the settings and pick the display format that you want to use.
Other Map Features
Your map may have a lot of
curvy lines drawn all over it. These are
called Contour lines. This means that
the map is a topographic map, or one that identifies the topography of the area
being mapped. The best part about a
contour map or topo map is that it lets you understand the hills and valleys on
a block, because the contour lines indicate the elevations throughout the
block. Each contour line represents a
specific elevation, say perhaps 1380m.
Contour lines are usually spaced 10m or 20m apart on a block map, or
perhaps 20m to 100m apart on a larger regional map. The closer the lines are together, the
steeper the slope.
If your map doesn't have
contour lines, but it has streams or creeks identified, there's a good chance
that you can figure out a rough idea of the hills and valleys on your own. Streams and creeks are usually identified in
blue. Look for a blue line, and follow
that line to where it ends. If the line
just stops suddenly, that's the highest part of the stream. Water flows downhill, so follow the creek
away from the starting point where the stream officially begins, and you'll see
where the block gets lower and lower in elevation. Perhaps the stream or creek will end in a
blue pond, or join another larger stream.
Sometimes you can also
guess approximate elevations on a map just by looking at the roads. The reason for this is because in hilly
country, the odds are slightly higher that the roads on the block will
generally be going uphill rather than downhill.
Of course, it is possible that roads can go downhill upon entering a
block, but that probably happens less than one third of the time, whereas more
than two thirds of the time the roads are either flat or go uphill. The reason for this is simple. Logging companies like to harvest the easiest
wood first, closest to the towns and mills.
The easier wood near the valley bottoms was probably harvested years
ago, and the logging companies are now making their way further and further up
into the steeper ground. Also, it's
easiest to build main roads along the valley bottoms and have then branches
going up into the blocks in the hills.
This method certainly isn't foolproof, but if you have to guess, you can
sometimes increase your odds of guessing correctly to be slightly better than
just 50/50.
Understanding Scales
Most maps have a small
"scale" on them. This will be
a number expressed as a ratio. On a map
showing a small area such as a single block, the ratio is often 1:5,000 or
1:10,000 or, for a very large block, maybe 1:20,000. On a larger "area map" which shows
a larger region of many blocks, the scale might be 1:30,000 or even 1:100,000
or larger.
This scale is a multiplier
to indicate how much real distance is covered by each part of the map. You multiply the distance on the map by the
large number in the ratio, to find the real-world distance. Usually, we think in terms of centimeters on
the map. Therefore, if you were to have
a map with a ratio of 1:5,000 then one centimeter on the map represents 5,000
centimeters in the real world. Ten
centimeters on the map would be ten times that amount, or 50,000 centimeters in
the bush. Now obviously, trying to measure
real-world distances in centimeters is an exercise in futility. So you can convert those numbers to meters
simply by dividing by 100, since there are 100cm in a meter. In other words, in the example where 1cm gave
us 5,000 centimeters, that's equivalent to 50 meters. In the second example of 10 centimeters on
the map, that becomes 50,000 centimeters or 500 meters in the bush.
These scales are really
useful because they can help a planter or a foreman plan for how many trees
need to go into an area. Let's say that
you're looking at a map with your foreman, and you've identified exactly where
your cache is located on the road on the map.
Let's also say that you're looking at filling a big pocket. You can get a ruler out and measure from your
cache to the back of the pocket. Let's
assume in this case that it's 4 centimeters on the map from your cache to the
back of your pocket, and let's assume that the scale on the map is
1:10,000. This means that the 4
centimeters on the map represents 400m in real-world distance. Let's also assume that your average spacing
on this block needs to be 2.5m between trees.
To go 400m to the back of your pocket, you need to bag up with 160
trees. You get this number by taking the
distance (400m) and dividing your average spacing between trees (2.5m). But you'll also want to be able to plant back
to your cache, instead of dead-walking, so you should take a minimum of about
320 trees in order to plant into the back, and then work back to your
cache. If you can carry even more than
320 trees in your bags, that's even better, because you can plant the extras at
the back before you turn around and plant back to your cache.
Geo-Referenced Digital
Maps
One of the biggest
revolutions in the planting industry since the introduction of LFH planting in
the mid-1990's has been the introduction of digital maps, and in particular,
geo-referencing.
When a digital map is
geo-referenced, this means that it has actual GPS location metadata embedded
within the file. Certain apps can load
these maps into your mobile device and correlate the map with the actual
current location of your mobile device, based on the GPS receiver in the
device. If the app determines that
you're actually "on" the map, it will display your exact location on
the map with a little marker indicating where you're located, perhaps a blue
dot or something similar. As you move
around the block with your mobile device, your location indicator moves around
on the map. It's just like using Google
Maps or other similar services, except that these geo-referenced PDF's are
generated by your silviculture forester and can show your planting blocks in
great detail. Naturally, Google Maps
focuses on towns and cities and government-maintained roads, so it usually
isn't any good on remote planting blocks.
At the moment, an app called Avenza PDF Maps seems to be the most
popular way to work with geo-referenced maps.
Another bonus of apps that
use geo-referenced maps is that you can do the same sort of distance
calculations as what I explained in the example with the ruler a few minutes
ago. You just tap two spots on the map
(presumably your cache and the back of your piece) and the app tells you the
exact distance between the two points.
You can also outline an area, such as your entire piece, and the app
will do an area calculation for you.
Let's say that your area calculation shows that your piece is
approximately 1.2Ha in size. If you're
aiming for 2000 stems/Ha and you do a good job with your density, you can assume
that your 1.2Ha piece should hold approximately 2400 trees. Being able to make calculations like this
really helps with planning.
Always Know Where You
Are
Understanding maps and
coordinate systems can be far more confusing than what I've explained here,
because the topic can be incredibly complex.
However, if you master the basics that I've explained here, you'll
understand all that you need to know to be comfortable with looking at a map
and trying to figure out where you are.
It's important that your foreman should always leave a map on the
dashboard of the truck, so if there's an emergency and the foreman is
incapacitated, the crew will be able to figure out exactly where they are and
relay that information to outside help.
If there isn’t such a map on the dash, ask your foreman to leave one
there for emergencies, with appropriate contact information to reach outside
help. If the foreman is the person who’s
seriously hurt, he or she will be really glad that they left this information
for the planters. Most companies require
that each crew have a written Emergency Response Plan with all of this
information, and with instructions on what to do in an emergency.
As a planter, you should
always know the number of the block that you're working on. A great idea is for the foreman to use a
dry-erase marker to write the block number on the rear-view mirror of each
truck every morning. You should also be
able to find the block number on the map on the dashboard.
-----
Here’s an Audio version of this material, in case you
want to listen while you’re driving, running, at work, or otherwise unable to
read or watch video:
Click on the down-arrow icon in the upper right corner of
the SoundCloud widget to download the mp3.
Once again, for further information about this series of
tree planter training information, visit:
I encourage you to share this information with anyone
else who might be interested. Thanks for
your interest and support!
-
Jonathan “Scooter” Clark
