Wednesday, June 12, 2013

Quiz on Modules 1-4 (with answers)


1) What is a data frame?

A map element that defines a geographic extent, a page extent, a coordinate system, and other display properties for one or more layers in ArcMap.

2) Why might you want more than one data frame in a map document?

Map layouts can display more than one data frame. So you might, for instance, use one data frame for your main map and a second data frame for your location map. 

3) One inch on a map equals how many feet on the ground at each different scale?

       1:24000  _2000__ feet                                              1:63360  _5280___ feet

       1:2400    __200__ feet                                              1:200      __216.67_ feet

       1:240      ___20__ feet                                              1:1          ____0.83_ feet


4) What is the difference between labels and annotation?

Labels are dynamic, they move for best display as the map is moved, so they're good for displays and web maps. Annotations are fixed at a location and scale and are best suited for publication mapping.

5) Why might you want to use layerfiles?

Layerfiles allow you to re-use symbology in other map documents. This saves you time and can help promote standards across an organization.


6) What is the best projection to use?

Trick question! There is no single best projection.  You must first define how the map will be used and what is the most important property to preserve - shape, area, distance or direction.  Only then can you decide the best projection to use.


7) Give an example of a vector dataset.

There are three types of vector datasets that define features using x,y and sometimes z coordinates:

  1) points - like wells, cities, fire hydrants

  2) lines   - like streams, roads, contours

  3) areas or polygons - like lakes, oceans, parcels

Sometimes the type of dataset will depend on the scale of the map. On a worldwide map a city might be a point, whereas it will be an area on a state or county map.

8) Give an example of a raster dataset.

Raster datasets represent space as an array of equally spaced cells. They are often used to portray data that is not sharply defined, data that changes continuously over a surface.

Satellite and aerial imagery are commonly used raster datasets where the cell values represent colors on the earth that we see as a picture.

Elevation surfaces, or digital elevation models (DEMs), are another example of raster datasets.

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