Week 5 Assignment - Dalal

Equidistant Projection measurements from Washington, D.C. to Kabul:

• Sinusodial Projection: Geodesic = 6,930.97 mi., Loxodrome = 8,088.14 mi., Great Elliptic = 6,909.31 mi.
• Equidistant Conic Projection: Geodesic = 6,976.59 mi., Loxodrome = 8,112.06 mi., Great Elliptic = 6,915.06 mi.

Equal Projection measurements from Washington, D.C. to Kabul:

• Bonne Projection: Geodesic = 6,918.66 mi., Loxodrome = 8,112.06 mi., Great Elliptic = 6,915.06 mi.
• Cylindrical Equal Area Projection: Geodesic = 6,994.40 mi., Loxodrome = 8,112.06 mi., Great Elliptic = 6,930.98 mi.

 

Conformal Projection measurements from Washington, D.C. to Kabul:

• GCS WGS 1984 Projection: Planar = 10,106 mi.
• Mercator Projection: Planar = 7,110 mi.

In this week's assignment, we produced different map projections based on the data that was given to us as well as the data that we added. We made Washington, D.C. and Kabul stand out with blue markers and then measured the distances between the two with each projection. Measuring was a little difficult than it seemed because every time I measure the same projection, I received different measurements. The measurements weren't drastically different but they were a couple numbers off. This made me realized that it can be difficult to receive precise measurements. I even compared my measurements for the conformal projections with my neighbor and noticed that our measurements were a little different. Having different measurements may raise alarm, unless I wasn't doing it properly. It also made me think of the perils of map projections and their significance since measurements vary.

As mentioned in class lecture, map projections vary and the distance between two points on each projection is rarely the same. Also in order to work with map projections and layering on ArcGIS, we have to make sure that spatial attributes on the layers are all the same for the shapefiles. If the spatial attributes aren't the same, then the layers and measurements will be completely off. For those who are new to ArcGIS, like myself and others, it can easily be brushed over unless we are taught to double check the spatial attributes, such as this assignment. Not double checking the spatial attributes or knowing that you need to match them up can cause problems and is a peril of map projections. In all of my map projections above, I made sure to double check my spatial attributes when working on the maps.

The significance of the various map projections is the different purposes they have and points they want to make. Each map projection has different story to tell as well as point of view. Some projections center their maps according to the country it is produced from while others make their own country look bigger than others when in reality it is the opposite. For example, in the Mercator projection under the conformal projections, Alaska looks bigger than Brazil when that's not the case. Making a country look bigger and in the center of a projection makes that country look more "powerful".

The potentials of map projections are to show the different points of views based on the producers of the projections. Also, the various projections allow for various purposes as well as specific purposes. For example, some map projections show the shortest distances from one location to another if the projection is accurate. Overall, map projections can be helpful to map users, however, the user has to be weary of the projection and fully understand various projections.