Monday, July 8, 2013

Non-Photo Method

Non-Photo Method

Example of Method 1


Tape Measures

Yellow Rope

Markers/tape (something that we could use to mark on the yellow rope across the stream to be able to measure it on land)




Yard Sticks

String (just in case we run out of yellow tape)

Graph Paper

Colored Pencils


Regular Pencils

Calculator (if needed for on-site conversions?)

Paper- to be used as a back drop so the laser can be seen clearly & to record distances


Materials in Question

-Control points (to place at the locations that we measure, then a picture can be taken from the bridge to be used as a reference when determining the outline of the bank between measured points)

-graph paper/colored pencils/ruler may only be necessary back in the lab to make the detailed graph unless someone is good at drawing and wants to make a rough sketch at the Duck Creek Site



-determine an appropriate unit conversion and print graph paper that would work best

-determine what we will define as the “outline” (sandy part vs bank)

-set up stakes/poles on both sides of the bank (place them where a straight line could be formed along the bank without any of them being in the water as in picture above…aka near the outermost bank edge)

                -use a laser to ensure they are in a straight line and use a protractor at each one to confirm the angle between the laser and the stakes are consistent (This step needs some more thinking…)

-use yellow rope to connect the lines

-measure cross sectional distances of stream as follows

                -First measure the distance from water’s edge to water’s edge

                -at the same point next measure the distance from stream to rope on both sides

-measure as many points along the stream as time and access will allow

-use unit conversion to graph outline on graph paper

-if we decide cameras would be a good idea, the control points should have been placed as measurements were taken then, once finished, take a picture from the bridge of the outline (I’m thinking a top-down view would be the most beneficial) and use this picture to get an idea of the stream outline in the areas between the measured points on the bank

-another method to fill in the “in-between” data if enough points cannot be found would be to compare it with David’s Photosynth images or Kyle’s Hugin work that stitched images together



Potential Problems

-the water level being too high and not allowing for an accurate distance measurement between the yellow rope and the stream

-the bank not being wide enough to be able to place stakes in a parallel line

-difficulty accessing the edge of stream due to bank steepness

-time consuming


Potential Solutions

-only use this method as a means of checking the accuracy of distances or general outline rather than an actual method to map the entire stream outline

                -the cross sectional distances could be used in combination with the photo method to determine accuracy of perspective correction

-could move stakes into the edge of the water on the interior line

                -pack some rain boots or old shoes because we’d be getting right in the stream

                -the methods for this would be very similar to the previous (and maybe even more ideal due to the water level that may not go down enough to reach the banks)

                - rather than placing the straight yellow string on the outside of the stream we could place it directly inside the innermost bank on each side and measure from the inside out as seen in the picture below

                                -this method may also be more accurate because the distance between the yellow string and the stream could be measured at the same level


Example of Method 2

If anyone sees anything missing or any other potential problems please let everyone know so we can think of a solution or revise the methods!


  1. Just wanted to jot down my thoughts on the Continuous Triangulation Method that we discussed briefly at the end of today. Uses two poles in the stream, two tape measures coming from those poles (at water level), and calling pairs of measurement numbers for each measured point along the stream outline. :-)

  2. Might not hurt to try one or both of these on the indoor stream. They may both be easy inside, but if they are hard in here, they'll be even harder out there....

  3. I'm going to need a further explanation of the triangulation method tomorrow if possible, I'm not sure I understand it completely. Either way I think the biggest challenge for each method is the height of the bank if no bank is available at stream level.

    Maybe it wouldn't hurt to take a quick run to the stream to check out the level/check how deep it is so we can revise/rule out certain methods??

    In regards to the "this step needs more thinking part" i really like susa's idea of the two lasers or just one laser once we mark the original line to make the 90 degree angles.