Archaeological Mapping and Coordinate Systems Flashcards

The primary goal for students who have uploaded a non-current map is to understand how to plot archaeological remains using an x-y coordinate system.
Any location on land can be measured precisely using both vertical and horizontal coordinates.
A specific reading consists of coordinates along two axes: the longitudinal (vertical) axis and the horizontal (latitudinal) axis.
Visualizing the grid on a map:
    - Orange lines extending from top to bottom represent longitudes.
    - Orange lines extending east-west represent latitudes.
    - A specific location, such as being in the middle of an "orange box," results in a unique reading for both axes.

Longitudes: Also known as meridians.
Latitudes: Also known as parallels.
The global coordinate system is divided into:
- $360^{\circ}$ of longitude.
- $180^{\circ}$ of latitude.
Subdivisions of a degree to ensure precision:
- Each degree ( $1^{\circ}$ ) is broken into $60$ minutes ( $60'$ ).
- Each minute ( $1'$ ) is broken into $60$ seconds ( $60''$ ).
The speaker uses a temporal analogy to explain the refinement of coordinates:
- A degree-minute-second reading is analogous to a year-month-day designation, narrowing down a general timeframe to a specific moment.

The United States uses 7.5-minute maps (also known as quadrangles).
Calculation for the number of maps required to cover the circumference of the United States:
    - Since there are $60$ minutes in a degree, divide $60$ by $7.5$ to find the number of maps per degree: $\frac{60}{7.5} = 8$ .
    - To find the maps needed for the full circumference ( $360^{\circ}$ ): $360 \times 8 = 2,880$ .
    - Therefore, it takes $2,880$ of these 7.5-minute maps to go around the circumference of the United States.

When moving east or west along the same horizontal line, the latitude remains constant while the longitude changes.
Example of fixed coordinates on a specific map edge:
- Longitude: $118^{\circ} 45' 00''$
- Latitude (top edge): $34^{\circ} 07' 30''$
The map features measurement guides (tick marks) to assist in measuring between the major edges.
On this specific map, markers are provided at $2.5$ minute intervals ( $2' 30''$ ).
Progressive longitude markers on the map (moving left to right/right to left):
    - $118^{\circ} 37' 30''$
    - $118^{\circ} 40' 00''$ (Represented by a tick mark labeled '40')
    - $118^{\circ} 42' 30''$
    - $118^{\circ} 45' 00''$
Progressive latitude markers on the map (moving top to bottom):
    - $34^{\circ} 07' 30''$
    - $34^{\circ} 05' 00''$ (Represented simply as '5' minutes)
    - $34^{\circ} 02' 30''$
    - $34^{\circ} 00' 00''$
Important Caveat: Students are instructed to disregard the UTM (Universal Transverse Mercator) system for this particular exercise. These are the sequences of three numbers found along the map lines. The focus must remain exclusively on the system consistent with degrees, minutes, and seconds.

Intersecting points are locations that fall exactly on the grid lines (the $2.5$ -minute intervals), making them easy to identify.
For locations that do not fall on an intersection, one must calculate the percentage of distance between the known markers.
Mathematical Calculation for Midpoints:
    - The distance between markers is $2' 30''$ .
    - Half of that distance is $1' 15''$ ( $1.15$ representing one minute and fifteen seconds).
    - To find the midpoint between $118^{\circ} 37' 30''$ and $118^{\circ} 40' 00''$ , add $1' 15''$ to the lower number to get $118^{\circ} 38' 45''$ .

Calabasas Peak:
    - Located between longitude $118^{\circ} 37' 30''$ and $118^{\circ} 40' 00''$ .
    - Estimated by visual measurement to be approximately one-quarter of the way from one side, leading to a rough estimation of $118^{\circ} 39' 00''$ or $118^{\circ} 39' 25''$ longitude.
    - Latitude is between $34^{\circ} 07' 00''$ and $34^{\circ} 05' 00''$ , estimated at nearly $34^{\circ} 07' 00''$ .
Brown Ranch:
- Longitude: Very close to the $118^{\circ} 42' 30''$ line. Because the ranch (marked by the letter 'b') is slightly to the left, it would be slightly higher than $30$ seconds, perhaps $118^{\circ} 42' 31''$ or $32''$ .
- Latitude: Between $34^{\circ} 07' 30''$ and $34^{\circ} 05' 00''$ . The midpoint is $34^{\circ} 06' 15''$ . Since the location is slightly below the midpoint, it is estimated at $34^{\circ} 06' 05''$ .
Pepperdine University (The 'X' mark):
    - This location happens to fall exactly on an intersection.
    - Latitude: $34^{\circ} 02' 30''$ .
    - Longitude: $118^{\circ} 42' 30''$ .
Malibu Point (Malibu Lagoon):
- Longitude: Located between $118^{\circ} 40' 00''$ and $118^{\circ} 42' 30''$ . The midpoint is $118^{\circ} 41' 15''$ . It is estimated to be roughly at $118^{\circ} 41' 00''$ .
- Latitude: Located between $34^{\circ} 00' 00''$ and $34^{\circ} 02' 30''$ . Because it is much closer to the northern line, it is estimated at $34^{\circ} 02' 10''$ .

Accuracy in plotting can be refined to within yards (or no more than a football field's length) using tools like spreading calipers.
Coordination with GPS allows researchers to find one another within approximately $50$ yards.
The instructor describes a typical field session near Malibu Canyon Road:
- Notable landmarks include PCH (Pacific Coast Highway), Malibu Beach, Cross Creek, and a local reservoir.
- A tunnel exists along the route heading north.
Crater Camp and Backbone Trail:
    - The Backbone Trail is a $35$ -mile long trail.
    - The parking lot for the Backbone Trail is the staging ground for the "map project."
    - In this project, the instructor hides flags and students must use coordinates to find them.
    - Coordinate estimate for Crater Camp:
        - Latitude: Just south of the $5$ minute line ( $34^{\circ} 05' 00''$ ), estimated at $34^{\circ} 04' 50''$ .
        - Longitude: To the right of $118^{\circ} 42' 30''$ , meaning the number decreases. Roughly estimated at $118^{\circ} 42' 25''$ .

Student Confusion Mentioned: The speaker acknowledges that students might be confused by the process of uploading maps and transitioning to archaeological plotting.
Specific Directives: The speaker explicitly tells the audience to ignore specific numbers on the map that relate to the UTM system, as they are not relevant to the current learning objective focusing on DMS (Degrees, Minutes, Seconds).
Future Assignment: The instructor announces a forthcoming assignment where students will need to locate four specific places on the map using rough x-y coordinates to ensure they do not "succumb to the wilderness."