Reading, usage and different aspects of map skills

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Steve Fri, Jan 14, 2022 10:07 PM UTC

This book provides knowledge about maps and their uses.

1. Chapter 2 Map Use and Map Reading will you have to go if you are in trouble (police stations,
municipality offices, fire brigade, hospitals, etc.).
Ferjan Ormeling, Netherlands
The kind of map you would have to bring with you, on
Maps can have many functions: they are used for paper or on a display, would depend on your mode of
instance for orientation and navigation, they can be used transportation, whether you would be walking, cycling,
for storing information (inventories) for management or going by car. For walking, a map on the scale 1:25,000
purposes (such as road maintenance), for education, would be deemed suitable (if available), for cycling the
terrain analysis (is a site suitable for specific purposes?) optimal scale would be 1:50 000, for motoring 1:200,000
and decision support (is it wise to build a town extension (and for planning a long trip a map 1:1,000,000).
in a south-westerly direction? Or to build a new
From the topographic map one may for instance derive
supermarket in that low-income area?). This chapter will
information on distances, directions and slopes. The Figure 2.2. The principle of contour lines. (©HLBG).
give some examples of what maps can contribute.
contour lines on these maps (formed by the
A. The map as a predictive tool (for navigation and intersections between parallel planes and the earth The procedure to assess the height of a specific point is
orientation) surface, (see figure 2.2), would allow you to find out the done by interpolation: In this case point A is located on
height of any point on a map. The slope then can be the 490m contour line, so its height is 490m; point B lies
With a topographic map (which describes the nature of deduced from the difference in height and distance halfway two contour lines with the values 510 and 500
the land and the man-made objects on it, see figure 2.7 between two points on the map. First, from the respectively (see figure 2.4). If the scale of the map is
and chapter 5)) of an area you are about to visit, you can orientation of the height figures with which the contour 1:6.000 and the distance AB is measured by a ruler to be
deduce in advance the nature of the terrain you are lines are labelled, one can see whether in a specific 5 cm, the actual distance in the terrain between the two
going to visit. Most important will be what the direction the slope goes up or down (figure 2.3). points would be 6.000x5cm= 30.000cm=300m. If the two
route/road will be like: will it be straight or have many points A and B are 300m apart and their heights are 490
bends, will it be steep, uphill or downhill? What kind of and 505 m, their height difference is 15m.
human settlements will you be passing on your trip? You
can find out their number of inhabitants from the size of
their names on the map!). What will the countryside be
like? What kind of vegetation, parcellation, crops, will
there be? Will you have to cross rivers or pass through
forests? What man-made objects will you sees on the
way – factories, canals, railways (infrastructure), and
what kind of cultural environment or cultural heritage
objects (castles, monuments, religious sites) will you find
on your way? And will you be able to pass everywhere,
or would there be restrictions, such as boundaries, or Figure 2.1 Map functions. (Drawing A.Lurvink). Figure 2.3. The meaning of contour labels. (©HLBG).
roads that are open only part of the year? And where
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2. Figure 2.5. Slope measurement diagram. VD means
vertical distance, HD horizontal distcance.(©Muehrcke,
Map Use)
Figure 2.4. Assessing a point’s height through
interpolation. (©HLBG).
The slope between these two points can be expressed as
a fraction (or ratio) between the horizontal distance
(rise) and the vertical distance (run), here 15/300 or
1:20. Slopes can also be given in percentages, for which
one must assess the number of vertical units for every
100 horizontal units. For 300/3=100m run the rise would
be 15m/3=5%. Finally, the slope can be expressed in
angles, which are given in degrees. In the triangle in Figure 2.7. Topographic map, with information
figure 2-5 formed by the horizontal and vertical categories highlighted. (©www.lgl-bw.de).
distances, the angle is expressed as the trigonometric
tangent of the slope angle. In a goniometric table, this can deduce the slopes of the terrain: if they are close
value can be retrieved and is found to be 3° (degrees). A together it will be steep, if they are further apart the
slope of 100% corresponds to a 45°slope (see also figure slopes will be more gently.
Why are slope values relevant? Because they will decide
whether you will be able to pass that specific road or
track, walking, cycling or motoring. Slopes of 1:40 (or
2,5%) are already almost too steep for trains; slopes of
1:10 (or 10%) are too steep for cycling and one would
have to get off one’s bike; slopes of 1:3 (or 33%) would
be almost too steep for a 4-wheel drive car (see figure
2.6). From the relative location of the contour lines we Figure 2.6. Slope effects. (©NSW Dept. of Lands).
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3. Now that we have found the road to be passable, we can GIS´s). Just compare the kind of information that can be
assess what we will encounter or see from the road: the read off different school atlas maps: in order to learn
natural and man-made environment, the infrastructure,
more about a specific area, like the Algarve in Portugal,
cultural objects and restrictions like boundaries, off-
on an general overview map in a school atlas (figure 2-8),
limits roads or areas, railway crossings, ferries or which shows it as a coastal plain with a hilly hinterland
tunnels. In figure 2.7 we can see what kind of individual up to 900m with the town of Faro as the main centre, we
objects can be seen from the road, like power lines,
motorways, agricultural roads, orchards, vineyards,
separate houses, greenhouses, factories or TV towers.
We will be further helped in our navigation by
conspicuous buildings or terrain characteristics on the
map that are easy to recognise in the field, such as a fork
or crossroads, conspicuous buildings like churches,
mansions or towers, rivers or the bridges over them.
The very names on the map provide information as well: Figures 2.8. The Algarve, in the south-western Iberian
different object categories have different letter styles. Peninsula according to the Bos atlas. (47th ed., 1971).
River names may be blue and tilting backwards, names
of small villages black and leaning fore wards, names of Figure 2.9.Inset map of the Bos atlas showing should link it on the basis of its location to other maps
agriculture. (Bosatlas 31sr ed., 1927). that show this area. If we link it to an agricultural map
cities rendered in capitals, the size of the fonts indicative
(figure 2.9) that also shows the Algarve, for instance, we
of the number of inhabitants of the named place.
would see that its coastal areas have Mediterranean
agriculture (cereal growing and vineyards) and the inland
Some countries denote the land use on their hills would have animal husbandry (esp. goats). A map
topographic maps by colours, other by repetitive on the occupational structure would show that the
symbols. Forests usually are rendered green on the map, Algarve has an exceptionally high percentage of
with symbols added to indicate whether they are people working in the services sector, which means,
coniferous, deciduous or mixed. In Eastern European considering its seaside location, in Tourism. From a
topographic map extra information is added by showing climate map (figure 2-10) we would see that the area is
reasonably humid; likewise that the population density is
the average height, circumference and inter distance
till rather low (110), when compared to the European
between the trees for every forest patch. Union (150) average. From a soil map of the region it can
be deduced that there are terra rossa soils. It can all be
B. Maps as links in information systems deduced from various atlas maps, although the process
Figure 2.10. Inset map shopping climate.(Bosatlas 31st to do so is rather laborious and roundabout.
Maps in atlases (see chapter 7) also can be regarded as ed.,1927).
geographic information systems (see chapter 3 for digital
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4. The advantage of the Alexander atlas is that it shows
local links or connections. It doesn’t teach you, however,
to establish links between the various data sets or maps
that is to establish the locations or addresses as links.
But the maps themselves are little wonders of well-
integrated and perfectly legible mapped information.
Figure 2.12. The kind of information different paper atlas
information systems might provide on a region.
So we can oppose the analytical approach in the
Bosatlas, which shows on each map ‘where is that
phenomenon?’, enabled by the fact that phenomena are
shown in isolation (either height layer zones or
Figure 2.11. The Algarve according to the Alexander
agriculture or climate, etc) and the synthesis-approach
Atlas. (©Ernst.Klett Verlag GmbH).
by the Alexander atlas (‘what is there?’). The graphical
land irrigated from the Guadiana reservoirs. The forests
It is conceivable to include more information in the show a blue tree symbol denoting oak trees. Their bark is approach by the latter invites one to make a journey of
overview map. The Alexander Atlas from Klett publishers a resource from which corks are produced. There is a discovery through the area (describe for instance what
would be an example (see figure 2.11). As the map has clear difference between the Portuguese Algarve coast you will see on a biking trip from Faro northwards). But
and the neighbouring Spanish coast, which cannot be one should realise the drawbacks of this method as well:
more detail, it has the advantage that specific terrain
deduced from figure 2.7, with its height layer zone in industrialised areas the overlapping symbols used
forms can directly be associated with specific land use or colouring. The scheme in figure 2.12 shows additional
land cover forms. The map shows that the Algarve mask land use, and nothing is communicated about the
differences in expression and related information
coastal plain has citrus growing and fruit trees, that tertiary (services) sector, which in this tourist area is so
density.
important. For getting to deal with information systems,
the prior approach might be more effective.
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5. Should the animation run too quickly, then it is also
possible to look at the individual maps produced for
each month, like the one in figure 2.14.
Figure 2.14. FAO world rainfall map for the month of
April.
Figure 2.13. Sugar production atlas spread from Canet’s
Atlas de Cuba (1949). C. Maps as inventories or switch boards
A third approach is to combine all information that is In order to speed up urban renewal, many cities have
relevant to a specific topic, like sugar in Cuba (figure information services for their citizens on which these can
2.13). Here on this atlas spread (a double page related to indicate where something is amiss. After entering the
one specific theme) both the actual sugar factories, the website of Rotterdam municipality I asked for the Figure 2.15. Map for reporting damaged ‘street
transportation network to get the sugar to the ports, and Utrechtsestraat, which then came up, large scale, furniture’. (©Rotterdam municipality).
the counrties where it is exported to are shown, with allowing me to pinpoint the location of a malfunctioning
diagrams illustrating which part of the arable land and of Another example would be the cadastral map: if I would
lamp post. For easier reference the house numbers are
the workforce is used for sugar production. like to know the current value considered appropriate
also given. In figure 2.15 this is shown. On the basis of
for my house, I would consult the municipal website
such reports the municipal maintenance services can
Climate data where I can log in and find out for what amount my
better plan their operations.
house is assessed by the municipality. It would also show
If you would like to know what is the best month to visit the assessments of similar houses in my neighbourhood.
a country, based on the likelihood of rain occurring Figure 2.16 is an example of such a cadastral map. The
during your trip, try the following FAO website: black numbers in the parcels refer to a list, the ledger or
http://www.fao.org/WAICENT/FAOINFO/sustdev/EIdirec land register in which are indicated the names of my
t/climate/EIsp0022.htm. It is an animated map which wife and me as the owners of the house, any
shows for every month the amount of rainfall expected, outstanding mortgages and the amount for which we
based on thirty years averages. In order to answer the bought it, and the date of the purchase.
question one would have to identify the country first,
and then look at the rainfall patterns changing over time.
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6. answer regarding this suitability, but when you address Figure 17a - Soil map; all soil units have codes that show
the characteristics of each soil unit (these would be its characteristics for a number of parameters. In 17b,
stored in the codes applied to the soil units on the map those soil units are suitable for the crop we want to raise,
or in the dataset on which the map is based) and tick off that are from the R soil family (so their code starts with a
the requirements for the crop you want to raise, then R) and have drainage characteristic d (see second
the system will highlight those areas that would be position of the codes).
suitable (figure 2.17b).
D. Map use steps
In all these map use cases, the first step was to find the
proper map for the assignment: a topographic map (see
chapter 5) or thematic map (see chapter 6), a large-or
small scale one, etc. The next step would be to find out
how the information was visualised (what symbols are
used for which information categories or objects), and
only then would one be able to find out relationships
between relevant objects, to recognise locations and see
what their characteristics are. All these steps are a part
of map reading.
Figure 2.16. Extract of a cadastral map. Black numbers A step further would be map analysis. That would entail
are cadastral numbers of parcels; red numbers refer to doing measurements (of slopes, distances, directions,
street addresses.(©Kadaster Nederland). surface areas, etc.) or counting objects. Finally, when I
would try to explain the situation (why are these objects
Soil maps2- are another form of inventories in which concentrated there? or Why are the southern slopes of
geospatial knowledge has been stored. Soil maps display that mountain range forested and the northern slopes
soil units, that is areas that have the same soil not?) my actions would be part of map interpretation,
characteristics, such as depth of the various soil layers, trying to find the reasons for a specific geographical
percentage of humus in the soil, chemical composition, distribution of objects or phenomena. In the case of the
permeability, ground water level, etc. The suitability for southern forested slopes, this might be because of
specific crops such as barley or sunflowers of a given prevailing southern winds that would bring rains to the
area would depend on these soil characrteristics, southern slopes, a higher temperature, or measures
combined with climate data such as the amount of against tree-eating animals, etc.
rainfall and the length of the growing season (number of
consecutive days with a temperature above 5° C). The
soil map (see figure 2.17a) won’t give an immediate
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7. In all these cases the map tells you something about the Figure 18 Maps as a window opening up reality (drawing
mapped area without the necessity of actually going A.Lurvink).
there yourself.
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