GIS Quiz 1

Where do you package a project?

“Start Packaging” tab and then save .ppkx to Box

difference between .aprx and .gdb

.aprx: project file

• project management for maps, layout, and data references

• specific to one project, and references data but does not store data in file

• has geodatabases within it!

.gdb: Geodatabase

• container used to hold a collection of datasets

• contains raw data that can be used across multiple projects

• stored within project folder

Where do you save a project?

“Project” tab, then save to Box

What is in the map tab?

layers of data

How do you add data to a project?

“Map” tab, then “Add Data”

How to switch map aesthetics?

choose from “Basemaps”

What is the “Contents” pane?

contains layered map contents (layered data)

How to get an Excel sheet from contents layer?

click “Attribute Table” and then “Tools” and Excel button

What is “Fields Views”?

can alter attributes of data from “Attribute Data” tab

How to change Symbology of feature class?

“Contents” pane, then “Symbology”

example of Map-Scale ratio

1:24,000 (1 in. on the map is 24,000 in. on the ground (or 2,000ft.))

Spherical coordinates

Latitude and longitude

Latitude (Parallels)

+/-90 degrees of latitude = north and south poles (respectively)

Longitude (meridians)

180 degrees of longitude east and west (east positive and west negative)

prime meridian

0 degrees of longitude

Degrees, minutes, seconds

• 1 degree = 60 minutes

• 1 minute = 60 seconds

Ex. Pittsburgh, PA

• 40°26’2” N latitude

  • 40°26’2” = 

  • → 40 + 26/60 +2/3600 =

  • → 40 + .43333 + .0005 = 

→ 40.43385° latitude

• 80°0’58” W longitude

  • 80°0’58” = 

  • → 80 + 0/60 + 58/3600 = 

→ 80.016° longitude

State Plane Coordinates

• Used by US local governments

• 125 zones 

UTM (Universal Transverse Mercator)

covers whole world (60 zones)

Map projections

Way to represent the curved surface of Earth on the flat surface of a map

• No distortion where surface touches Earth 

• “Secant” projection if surface pierces Earth

• “Transverse” projections if rotated 90° 

Conformal Projection

• Typically a cylindrical projection

• Flattens globe

• Direction preserved

  • Parallels and meridians at right angles

• Leads to major distortion!!!

  • size/shape/area of large objects is distorted as scale approaches infinity at poles

  • So bad for global maps, but good for direction

Equivalent Projection

• Conic projection

• Preserves accurate area

• Uses 2 standard parallels 

• Shape (and scale) not preserved, but minimal distortion between the standard parallels

• Best suited for east-west landscapes

Compromise Projections

• Neither equivalent nor conformal

• Meridians curve gently, avoiding extremes

•  Doesn’t preserve properties, but “looks right”

• Ex. Robinson Projection

How to change projections?

In “Contents” pane, right-click and press “World Projections”

Cartograms

• Distorted maps depending on another data source

• Ex. dependent on social aspects, like median household income by region

TIFF (.tif) (tagged image file format):

common image format for high quality images

GIF (.gif) (graphic interchange format):

ideal for drawings w/ relatively large areas and few color variations

JPEG (.jpg) (Joint Photographic Experts Group):

most widely used format for photos/ images that have a lot of color variation

“Feature attribute table” of a feature class

Every feature has a record w/ attribute values

How to see XY Data?

• Go to table of attribute by right-clicking on it →

→ hit “Display XY Data”

Data Table Format

• Rectangular table w/ one value per cell

  • Columns (fields) are attributes 

  • Rows (records) are observations

ANSI Codes (geocode)

Basically, add new groups of numbers to refine location down

Shapefile: ESRI Legacy Format

Multiple files, all having the same name but different file extensions

Reading: What is map thinking?

“the process through which elements of experience are abstracted, identified, joined, and then transformed into a common narrative.”

thinking of broad aspects of what could go into map and the reasons behind making a map, thus resulting in mapmaking

Reading: How do maps represent scientific thinking?

“It is the scientific thinking embodied in the map that makes discoveries available to us all.”

basically, maps —> scientific thinking (ex., in mapping disease)