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Samoan Armchair Archaeologist
Tutorial - IV: Recognizing Features

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IV. Recognizing Archaeological Features on LiDAR

Archaeological Features from Lalomanu, Upolu

At first glance the mass of archaeological features that can be seen on the Samoan LiDAR is almost overwhelming. We hope, in the following tutorials, to make that experience less traumatic, and if possible, enjoyable or at least educational.

The archaeological features have been grouped into ten (10) basic feature types that with some practice are easily recognizable on LiDAR (Channels, Earth Ovens, Forts, Pits, Platforms, Star Mounds, Stone Piles, Terraces, Walkways, Walls). General “LiDAR” rules will be discussed below, and each feature type will be covered in a separate tutorial section. Some or all of these features types may be located within any given survey square.

You may want to concentrate on a particular type of feature when you do your work, but it is necessary to at least become familiar with all 10 feature types to make sure that your work is accurate and verifiable.

Please review the LiDAR Information - Tutorial section of the CSS LiDAR Map Server Web Page before continuing.

Below is a menu with the general LiDAR rules and the 10 basic feature/site types leading to a tutorial on recognizing each on LiDAR:

Recognizing Features Menu

    a. General Rules
    b. Channel
    c. Earth Oven
    d. Fort
    e. Pit

    f. Platform
    g. Star Mound
    h. Stone Pile
    i. Terrace
    j. Walkway
    k. Wall

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General “Rules” [for SkyView Factor LiDAR images]:

1.  Light = High :
     Normally the lighter/whiter an object is on LiDAR, the taller its profile.
     Roads and large paved/cleared areas are an exception.
     Modern buildings, and trees usually have the lightest/whitest presents on the images. But any object (walls, platforms, terraces) that is not at ground level also appears lighter than its surroundings.
2.  Dark = Low :
     In the reverse, normally deep or depressed spaces (compared to their surroundings) appear dark
     (holes, rivers , ravines, spaces between trees, collapsed lava tubes, craters, etc.).
3.  Light surrounded by Dark = raised structure :
     (platform, terrace, wall, elevated walkway, walled walkway)
4.  Dark surrounded by Light = depressed structure :
     (channel, pit, earth oven, river, modern road, foot path)
5.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
6.  ALL RULES ARE NOT ALWAYS RULES!!
     Mother nature makes her own rules and doesn't always follow "Human Rules".

[Back to Recognizing Features Menu]

Channel:

Channels are more often found in geologically old soils. One finds more channels on the NE, East, and SE coast of Upolu where there is less rock and deeper soil.

1.  Channels and walls are not “usually” found together
     (but this is not always true).
2.  Modern roads may be built over old Channels.
     (demonstrating use, reuse, and modification over time).
     (View aerial photos below for comparison.)
3.  Channels come in all shapes and sizes.
      (straight, zigzagged, curved, undulating)
      (width/narrow, short/long, deep/shallow)
4.  They appear in multiple shades of gray [

;

  ]
     (light gray to darker gray depending on depth (see a2 above))
5.  Alone or in conjunction with other channels/walls they appear to form enclosed/bounded areas
     (but this is not always true; also these "enclosures" may be temporal and not functional)
6.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
7.  Use the Polyline tool

to mark Channels. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored Channels

that can be “seen”

  on the image on the right.
Practice in recognizing Channels:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" Channel ("channelsample1.jpg").
5.  Next select the photo with the blue "vectored" Channels ("channelsample2.jpg")
6.  Pick (visually) a specific Channel (blue vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular Channel's shape and color.
  c.  Repeat this process for various other Channels (blue vectors) in the photo to become familiar with the variation in Channel shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in Channels, close the tabs containing the LiDAR channels and continue the tutorial.

Compare the LiDAR above with what can be seen (or not seen) on these aerial photos.

What you can see without LiDAR:

Try the same steps as above on these two aerial photos to see the differences between what you can see using LiDAR and what appears on Aerial Photos.

[Back to Recognizing Features Menu]

Earth Oven:

1. Earth Ovens, when seen on LiDAR, have a distinctive donut shape (a light ring with a dark center –

)
2.  The difference in the darkness of the center is caused by the depth of the central depression (see a2 above).
3.  The number of earth ovens that can be seen on LiDAR varies greatly from one area to another.
4.  Though earth ovens are relatively easy to see on LiDAR they are much harder to see on aerial photos, but are still recognizable in many instances.
     (View aerial photos below for comparison.)
5.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
6.  Use the Circlemarker tool

to mark Earth Ovens. (Covered in Tutorial VI )

See the examples below:

On the left are some of the vectored earth ovens

that can be “seen” Earth Oven

  on the image on the right.

Practice in recognizing earth ovens:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" earth ovens ("umusample1.jpg").
5.  Next select the photo with the light blue "vectored" earth ovens-dots ("umusample2.jpg")
6.  Pick (visually) a specific earth oven (light blue vector-dot):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular earth oven's shape and color.
  c.  Repeat this process for various other earth ovens (light blue vectors-dots) in the photo to become familiar with the variation in earth oven shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in earth ovens, close the tabs containing the LiDAR earth ovens and continue the tutorial.

Fort:

Forts are one of the more widely dispersed features found in Samoa.
1. When seen on LiDAR many earth Forts have a distinctive linear shape with one "light" and one "darker" side

  [Click picture to enlarge.])
2.  In their simplest form they are a ditch (dark) and bank (light) that stretch across the top of a plateau from ravine to ravine.
3.  They can also be quite intricate and may be made up of several palisades covering entire hillsides.
4.  They are usully found alone, but have also been found in groups in certain areas. (see: "3 Forts" below)
5.  They may be mixed with other features, especially terraces.
6.  Because of their preferred location (stretching across a narrow plateau) many forts have modern roads built across/over them.
7.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
8.  Use the Circlemarker tool

to mark Forts. (Covered in Tutorial VI )

See the LiDAR examples below: (select photo to enlarge)

Fort with road across left & right side.	Series of forts and terraces.	Fort with roads across center.
Fort with road across left side.	Fort with road across left side.
		3 Forts (2 small forts on top with roads on left. 1 large fort on bottom trisected by 3 (or more) roads left, center, and right.
Fort with road across center.	Fort on peninsula surrounded by river.	Fort with road across bottom.

[Back to Recognizing Features Menu]

Pits / Depressions:

Pits differ from earth ovens in that they are usually irregularly shaped, often elongated and lack the distinctive “donut” shaped light ring around the dark center found in earth ovens. (see the LiDAR Info Tutorials on Pits for description and uses).

1.  Pits may be found together with other features (platforms, walls, earth ovens, etc), but are also often found alone.
2.  Pits though usually oblong in shape, come in variety of shapes and sizes.
     (round, oblong, rectangular, square, irregular).
3.  Pits may be found in different types of terrain (hillsides and flat areas).
4.  Pits have a distinctive dark center (deep area/pit) and some display a lighter area of removed fill dirt, usually on one side or end.
     (the darker the central area, the deeper the pit (see a2 above))
5.  Pits have a similar appearance to collapsed lava tubes (dark center) but are much smaller (5-20 meters in size).
6.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
8.  Use the Circlemarker tool

to mark Pits. (Covered in Tutorial VI)

See the LiDAR examples below:

On the left are just some of the vectored Pits Pits

that can be “seen” Pits

  on the image on the right.
Practice in recognizing Pits:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" Pits ("pitsample1.jpg").
5.  Next select the photo with the blue "vectored" Pits ("pitsample2.jpg")
6.  Pick (visually) a specific Pits (blue vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular Pit's shape and color.
  c.  Repeat this process for various other Pits (blue vectors) in the photo to become familiar with the variation in Pit shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in Pits, close the tabs containing the LiDAR Pits and continue the tutorial.

Platform:

Platforms come in all sizes and shapes. They are made of both earth and/or stone. They range in size from 4m across to over 100m in length (for clarity purposes any “pile of rocks” that is less than 4m in diameter is classified as a “stone pile”).

1.  Platforms are “usually” found together with other features (platforms, walls, earth ovens, etc)
     (but this is not always true).
2.  Platforms come in all shapes and sizes..
     (round, oblong, rectangular, square, irregular).
     (4 to 100 meters plus in width/length).
3.  Modern roads and/or houses may be built over platforms or portions of platforms distorting their original shape.
      (demonstrating use, reuse, and modification over time)
     (View aerial photos below for comparison.)
4.  They usually have a light gray or white central area with darker gray around the edges.
     (the darker the area around the edges, the taller the platform)
5.  They may appear to be enclosed (practically or totally) by channels/walls.
     (but this also is not always true)
6.  Zoom in and out to help clarify a platform’s shape
7.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
8.  There is a special “category” of platform of “irregular” shape which is given its own Feature Type (Star Mound – see below) and therefore should not be included in “Platforms”.
9.  Use the Polygon tool   Shape Tool

to mark Platforms. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored platforms Platfprm

that can be “seen” Platform

  on the image on the right.
Practice in recognizing platforms:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" platforms ("platformsample1.jpg").
5.  Next select the photo with the purple "vectored" platforms ("platformsample2.jpg")
6.  Pick (visually) a specific platform (purple vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular platform's shape and color.
  c.  Repeat this process for various other platforms (purple vectors) in the photo to become familiar with the variation in platform shape and color.
7.  Use the aerial photo (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in platforms, close the tabs containing the LiDAR platforms and continue the tutorial.

Star Mound:

Star Mounds are a special category of platform (see Platforms above). Although labeled “Star Mounds”, not all Star Mounds are star shaped, and should more appropriately be labeled “cog mounds”. (See the Map Server LiDAR Tutorial for more information.)

1.  As Star Mounds are a specific type of platform, all the criteria listed above for platforms apply.
2.  Despite their name, Star Mounds come in all shapes and sizes. They may have from one (?) to eleven cogs or arms.
3.  Their distinguishing features are their cogs or arms that protrude along the sides. See examples below:

4.  The number of Star Mounds that can be seen on LiDAR varies greatly from one area to another.
5.  Their clarity (the ability to see the cogs) varies greatly depending on local vegetation and many are only discernable by their amorphous shape and distinctive dark irregular border. (The dark border is usually caused by “borrow pits” and/or the elevated sides of the star mound.)
6.  Star Mounds may appear on the edge of ravines but also appear on more even terrain.
7.  They may appear among other features or apparently in isolation.
8.  Their size varies greatly with many between 15-30 meters in diameter.
9.  Not all cogs (arms) are visible for all star mounds and they may only appear with an irregular/jagged outline. In other cases the cogs are quite clear and easily counted.
10.  Star Mounds are relatively easy to see on LiDAR but very hard to see on Aerial Photos. (compare below).
11.  Star Mounds can be found far inland or relatively close to the coast.
12.  Use the Circlemarker tool

to mark Star Mounds. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored Star Mounds

that can be “seen”

  on the image on the right.
Practice in recognizing Star Mounds:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" star mounds ("SMsample1.jpg").
5.  Next select the photo with the red "vectored" star mounds ("SMsample2.jpg")
6.  Pick (visually) a specific star mound (red star):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular star mound's shape and color.
  c.  Repeat this process for various other star mounds (red star) in the photo to become familiar with the variation in star mounds shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in star mounds, close the tabs containing the LiDAR star mounds and continue the tutorial.

Stone Pile:

Stone Piles are a diminutive subset of platforms. As the name implies they are amorphous piles of stone. Any platform (pile of rocks) smaller than 3m in diameter is considered a “stone pile”. (see the LiDAR Info Tutorials on Stone Piles for description and uses).

1.  Stone piles are “usually” found together with other features (platforms, walls, earth ovens, etc)
     (but this is not always true).
2.  Stone piles may be found in clusters or singularly.
     (View aerial photos below for comparison.)
3.  Stone piles thought relatively small, come in all shapes and sizes.(<3m in diameter).
      (straight, zigzagged, curved, undulating)
      (width/narrow, short/long)
4.  They appear in multiple shades of gray
     (light gray to darker gray depending on height (see a2 above))
5.  They may appear to be enclosed (practically or totally) by channels/walls.
     (but this also is not always true)
6.  Zoom in and out to help clarify their size and shape.
7.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
8.  Use the Circlemarker tool   Point Tool

to mark Stone Piles. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored Stone Piles

that can be “seen”

  on the image on the right.
Practice in recognizing Stone Piles:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" Stone Piles ("spsample1.jpg").
5.  Next select the photo with the dark blue "vectored" Stone Piles ("spsample2.jpg")
6.  Pick (visually) a specific Stone Piles (dark blue vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular Stone Piles's shape and color.
  c.  Repeat this process for various other Stone Piles (dark blue vectors) in the photo to become familiar with the variation in Stone Pile shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in Stone Piles, close the tabs containing the LiDAR Stone Piles and continue the tutorial.

Terrace:

Terraces differ from platforms in that they are not built by carrying in new material (rock or earth) but by the relocation of material (usually earth) cut out of the side of a slope forming a flat area by leveling the slope (see the LiDAR Info Tutorials on Terraces for description and uses).

1.  Terraces are “usually” found together with other features (platforms, walls, earth ovens, etc)
     (but this is not always true).
2.  Modern roads may be built over or cut through Terraces.
     (demonstrating use, reuse, and modification over time).
     (View aerial photos below for comparison.)
3.  Terraces may be found in clusters blanketing entire hill sides or singularly.
4.  Terraces though usually oblong in shape, come in all shapes and sizes.
     (round, oblong, rectangular, square, irregular).
5.  Terraces have a distinctive light center with a darker “up hill” side and a lighter “down hill”.
     (light gray to darker gray depending on height (see a2 above))
5.  Terraces are found in hilly or mountainous terrain.
6.  The number of terraces seen on LiDAR varies greatly from one area to another.
7.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
8.  Use the Polygon tool   Shape Tool

to mark Terraces. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored Terraces Terrace

that can be “seen” Terrace

  on the image on the right.
Practice in recognizing Terraces:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" Terraces ("terrsample1.jpg").
5.  Next select the photo with the purple "vectored" Terraces ("terrsample2.jpg")
6.  Pick (visually) a specific Terrace (purple vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular Terrace's shape and color.
  c.  Repeat this process for various other Terraces (purple vectors) in the photo to become familiar with the variation in Terrace shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in Terraces, close the tabs containing the LiDAR Terraces and continue the tutorial.

Walkway:

Walkways are of two types (see the LiDAR Info Tutorials on Walled Walkways and Elevated Walkways.

1.   Walled Walkways and Elevated Walkways may be found together (sometimes forming a continual walkway with one type leading into another.)
2.  Ancient walkways are often repurposed, widened and reused with modern roads rebuilt over the old walkways.
     (demonstrating use, reuse, and modification over time).
     (View aerial photos below for comparison.)
3.   Walkways usually form straight or gently curving forms.
4.   Walled walklways vary in construction from well formed walkways several stones thick to collapsed stones walls or simple “lengthener alignments” of rock (presumidly caused by reuse of their stone in other "more recent" features).
5.  Walled walkways form a destinctive parallel row of walls with a dark center.[   walkway

;

  ]
     (Walkways are rarely as clear as the samples above.)
6.  Elevated walkways on LiDAR are often difficult to discern from large walls and many times they can only be destinguished from one another by surface observation.   walkway

7.  Ancient walkways may be linked and appear to form an interconnected system.
     (but it is difficult to know for sure from LiDAR alone.)
8.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
9.  Use the Polyline tool   Line Tool

to mark Walkways. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored walkways walkway

that can be “seen” walkway

  on the image on the right.
Practice in recognizing walkways:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" walkways ("walkwaysample1.jpg").
5.  Next select the photo with the red "vectored" walkways ("walkwaysample2.jpg")
6.  Pick (visually) a specific walkway (red vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular walkway's shape and color.
  c.  Repeat this process for various other walkways (red vectors) in the photo to become familiar with the variation in walkway shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in walkways, close the tabs containing the LiDAR walkways and continue the tutorial.

Wall:

Walls are more often found in geologically newer soils which contain an abundance of rock. One finds more walls on the West coast of Upolu and on Savaii where there is more rock.

1.   Walls and channels are not “usually” found together
     (but this is not always true).
2.  Ancient walls are often repurposed or reused and modern walls may be rebuilt over old walls.
     (demonstrating use, reuse, and modification over time).
     (View aerial photos below for comparison.)
3.   Walls come in all shapes and sizes.
      (straight, zigzagged, curved, undulating)
4.   They vary in construction from well formed walls several stones thick and one or more meters in height to flimsy stacks of single stones or simple “lengthener alignments” of rock.
5.  They appear in multiple shades of gray [   Wall

;

  ]
     (light gray to darker gray depending on height (see 2a above))
6.  Alone or in conjunction with other walls/channels they appear to form enclosed/bounded areas
     (but this is not always true; also these "enclosures" may be temporal and not functional)
7.  Use the aerial photos on the map page (slider) to view and compare (eliminate) modern structures.
9.  Use the Polyline tool   Line Tool

to mark Walls. (Covered in Tutorial VI )

See the LiDAR examples below:

On the left are just some of the vectored walls Wall

that can be “seen” Wall

  on the image on the right.
Practice in recognizing Walls:

Read ALL of the steps below before trying them.
1.  Click on each of the photos above to enlarge each in a new tab.
2.  You will need to return to the "Recognizing Features" tab to access both photos.
3.  Now that both photos are open in separate tabs you can easily move back and forth between photos (and the directions - "Recognizing Features") by selecting a tab.
4.  Start by viewing the "unmarked" walls ("wallsample1.jpg").
5.  Next select the photo with the purple "vectored" walls ("wallsample2.jpg")
6.  Pick (visually) a specific wall (purple vector):
  a.  Switch photos and compare what you see.
  b.  Click back and forth between the photos (steps 4 and 5) until you become familiar with that particular wall's shape and color.
  c.  Repeat this process for various other walls (purple vectors) in the photo to become familiar with the variation in wall shape and color.
7.  Use the aerial photos (below) to view and compare (eliminate) modern structures.
8.  When you are confident that you can recognize the variations in walls, close the tabs containing the LiDAR walls and continue the tutorial.

Centre for Samoan StudiesSamoan Armchair ArchaeologistTutorial - IV: Recognizing Features

IV. Recognizing Archaeological Features on LiDAR

Centre for Samoan Studies
Samoan Armchair Archaeologist
Tutorial - IV: Recognizing Features