Cartographic Projections

Dear bloggers, I' m going to upload our work of this week about Cartographic projections.

1. Cartographic Projections

- ROBINSON.

1.       Purpose:

Its primary purpose is to create visually appealing maps of the entire world. It is a compromise projection; it does not eliminate any type of distortion, but it keeps the levels of all types of distortion relatively low over most of the map. 

2.       Distortion – Types?

There are different types of distorsion. We can found:

·         Shearing and Conformality.

Robinson projection is not conformal; shapes are distorted more than they would be in a truly conformal projection. However, shapes are not distorted very badly within about 45° north or south of the equator or within about 45° of the map's central meridian. Beyond these limits, shape distortion can be quite severe.

·         Tearing

Robinson maps show lines of latitude as parallel straight lines and lines of longitude as nonparallel lines that become increasingly curved as you move farther away from the map's central meridian. The poles are shown as straight lines and the east and west edges of the map are curved lines 180° from the map's central meridian.

·         Compression:

Robinson projections are not equivalent; they do suffer from compression. However, the amount of area distortion is generally low within about 45° of the equator.

·         Equidistance:

The Robinson projection is not equidistant; there is no point or points from which all distances are shown accurate

·         Azimuthality:

The Robinson projection is not azimuthal; there is no point or points from which all directions are shown accurately.

3.       Distortion – Areas that are most distorted?

The greatest distortion occurs near the north and south poles. The range of acceptable distortion in these maps is usually 45 degrees north to south.

4.       There is more than one version?

No, is unique.

5.       Problems?

This kind of projection isn’t equivalent so it avoids these properties.

Distortion close to the poles is severe, but quickly declines to moderate levels moving away from them. The straight parallels imply severe angular distortion at the high latitudes toward the outer edges of the map, a fault inherent in any pseudocylindrical projection.

    6. Socio-Cultural Implications of using it as a learning resource?

This type of projection usually uses because makes the world “look right”. Better balance of size and shape of high-latitude lands than other projections.

- MERCATOR

1. Purpose:

The Mercator projection was developed in 1569 by Gerardus Mercator as a navigation tool. Like the Peters map, the grid is rectangular and lines of latitude and logitude are all parallel. The Mercator map was designed as an aid to navigators since straight lines on the Mercator projection are loxodromes or rhumb lines -- representing lines of constant compass bearing -- perfect for "true" direction. If a navigator wishes to sail from Spain to the West Indies, all they have to do is draw a line between the two points and the navigator knows which compass direction to continually sail to reach their destination.
 2. Distortion – Types?

The Mercator Projection always has the Equator as its Standard Parrallel.  Its construction is such that the lines of longitude and latitude are at right angles to each other – this means that a world map is always a rectangle.

Also, the lines of longitude are evenly spaced apart.  But the distance between the lines of latitude increase away from the Equator.  This relationship is what allows the direction between any two points on the map to be constant true direction.

While this relationship between lines of lines of latitude and longitude correctly maintains direction, it allows for distortion to occur to areas, shapes and distances.  Nearest the Equator there is little distortion.  Distances along the Equator are always correct, but nowhere else on the map.  Between about 15° north and south the areas and shapes are well preserved.  Further out (to about 50° north and south) the areas and shapes are reasonably well preserved.  This is why, for uses other than marine navigation, the Mercator projection is recommended for use in the Equatorial region only.

Despite these distortions the Mercator projection is generally regarded as being a conformal projection.  This is because within small areas shapes are essentially this.

3. Distortion – Areas that are most distorted?

·         Europe (9,7 millions of Km2) appears bigger than South America (17,8 millions of km2).

·         The URSS (22,4 millions of km2) appears bigger than Africa (30 millions of km2).

·         The Ecuador doesn´t appear in the center of the map. Two thirds of the map represent the North hemisphere, a third to the South hemisphere.

·         Scandinavia (1,1 millions of km2) is represented bigger than India (3,3 millions of km2).

·         Greenland (2,1 millions of km2) appears bigger than China (9,5 millions of km2).

·         The eurocentral distortion is kept if we compare concrete countries: Italy has equal size that Somalia (the latter is twice major); Sweden turns out to be twice major that Egypt, when it is the other way around.
    
4. There is more than one version?

 No. There is only one versio

 5.  Problems?

The problem is that Mercator does not respect the real size of the continents, making Europe and North America bigger than others.

6.  Socio-Cultural Implications of using it as a learning resource?

It is one of the most used in books and when teaching children because of its rectangular shape. This way children can see all the countries properly. But there are massive distortions. Europe for example appears bigger than other continents when it is not really like this. This is due to the importance Europe has always had. It is considered the most important continent in the world that´s why Mercator did this.

- AZIMUTHAL

1.       Purpose

It is the best one for projecting small scale maps.

          

2.       Distortion – Types?

It has radial symmetry in the scales and hence in the distortions: map distances from the central point are computed by a function r(d) of the true distance d, independent of the angle; correspondingly, circles with the central point as center are mapped into circles which have as center the central point on the map.

3.       Distortion – Areas that are most distorted?

It depends on where the center is fixed. As you go to the edges it is more distorted.

4.       There is more than one version?

               Yes.

5.       Problems?

You cannot see the whole world at once; it is only useful for one hemisphere.

6.       Socio-Cultural Implications of using it as a learning resource?

These maps are useful for navigation.

2.       COMPARISON BETWEEN MAPS.

First, is important that you know that we have chosen Egypt and Sweden to do the comparison between the different projections, and in the reality, Egypt is bigger than Sweden.

In the Robinson projection we saw that both countries look quite similar in size. In this projection as in the azimuthal projection, Egypt is on the northern hemisphere.

In Mercator projection, Sweden is bigger than Egypt although Egypt has got more km2 than Sweden in the reality.

Egypt is closer to the Equator line in this projection.

More importance is given to Sweden than Egypt because this projection was made for sailing giving more importance to colonist countries.

In the Azimuthal Projection the difference in size between these two countries is the clearest of the 3 types of projection.

Egypt is on the northern hemisphere as in Robinson projection.

1 3. WHAT COULD BE THE BEST PROJECTION FOR BEING USED IN A CLASSROOM?

In our case, there wasn’t any type of discussion with this theme because we were agree with the best cartographic was Robinson projection because at school we only focus in countries, not in pols and this projection only has got a distortion in pols and his shape is adequate to have a learn easily.

4. SEARCH ANOTHER EXAMPLE OF ONE SPECIFIC MEDIA:

We have chosen an example of media, the shape of heart.

Everybody know that the real form of heart isn´t this <3 but we usually use it to draw o to represent the love. In some games, the heart appears in the center of the body instead of the left part. This can produce a distortion in the vision of the little students.

A way to finish with it, maybe will be teacher teach children since they were very little to draw the heart with its real shape and represent the different feelings with it.

5. TREASURE HUNT

A treasure hunt is one of many different types of games which can have one or more players who try to find hidden articles, locations or places by using a series of clues.

In our animals treasure hunt you should follow next directions:

• -          You should change the message next to the pig if necessary.
• -           Print and cut along the horizontal lines.
• -           Fold each clue in half so only the animal is showing.  
• -          Put tape or sticky tack on the clue side and place clues all around the house so the animals are showing. 
• -          Give this first clue to the team.  Children read each clue and search to find the matching animal.    

We have all of this work in our presentation.

Cartographic projections from Almuudena1

I’m going to include the complete treasure hunt to play with our futures students.

I’m sure that it will be so funny! (:

Animal Scavenger Hunt from Almuudena1