question for technically minded

How to buy or make a ruling device to show depth of potholes or utility cover-lids, while photographing? Can manage if one person holding a rule, and the other person focusing a camera to take a close-up showing the measurement. But cannot do on my own with current tools.

I carry a tape measure and flat edge (clipboard) to measure some cycling hazards I see while cycling. But there are times when one wants to photograph to persuade the authority to fix, or proof if the hazard is a dangerous work practice.

Examples include work at an SA Water cover-lid where the cover-lid was left more than 20mm below the road surface, surrounded by a much deeper and large hole. This was in a turn right lane which a cyclist might enter, and downhill! I reported it twice but it was months before remedied. An example last week was of gas company workers cutting four holes in a bicycle lane, all outside the Austroads limits, the deepest one 55mm deep.

Might be easier to persuade some authorities to improve their standards or enforcement of them, if photographic evidence.

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Comment by Michael Moses on May 27, 2011 at 23:29: Heather, something like they use in forensic photography, you could use anything that can be used to scale the image you are photographing. If you had something like the 2nd image it would need to stand more upright, otherwise the angle could distort the actual measurements.

Not sure if i can print something like this for you at work, i have to check to see if i have a material suitable.

will keep you informed

cheers

Comment by Brian Jenkins (BJ) on May 28, 2011 at 0:55: Using two items. The first being a small diameter round piece of wood with depth markings - like a water depth marker on road creek crossings. The second, a simple ruler long enough to span the hole, resting next to the marking pole. Where the ruler touches the pole will show the depth.

Comment by heather on May 28, 2011 at 17:43: This is an example photo of a hazard that was left without any warning cones. It does indicate that the hole exceeds the Austroads depth of 19mm to be a cycling hazard. In a bicycle lane, on the corner of Prospect and Alpha Roads.

One person held the tape measure (a 1.5m aluminium ruler in the blue case) while the other person focused the camera. Seeking a tool that is self-standing, so that only one person required for the task.

Michael, I like your inspiration from forensic science. For my task, need only metric and marked in multiples of 5mm in black on a bright yellow background (similar to the tape measure). Could one attach at the bottom and back a small piece of dense metal (eg lead), to encourage the measure to stand upright? Inspired by a plumb bob. Do not want the measure too wide, or the stabilising metal too big, because sometimes the hole area will be small. Austroads recognises that some deep narrow slits in the bitumen surface are cycling hazards.

If the rule were up to 200mm long and the straight edge were 300mm long, then I could easily carry both on my bike where ever I cycled. I would prefer both to be in firm metal and hopefully light and non-rust aluminium. I have found potholes wider than 300mm so that could be a prob if wanting to photograph with one person. Unless the small upright rule could be balanced against the tape measure stretching across the hole. I wondered for a moment about the straight edge having a slot in it to help hold the measure. If a slot in the middle, think this could obscure the digits. Perhaps a tiny bit out of one edge, so the measure rests in the slot. But not a slot so deep that a shadow cast on the digits.

Michael, what so you think?

Comment by heather on May 28, 2011 at 17:46: Perhaps the straight edge could have some measurements, starting from zero in the centre, which would also give an impression of hole width in the one photo.

Comment by D-shackle on May 28, 2011 at 18:22: Here are some devices that archeologists use for scaling photos. Notice that they generally don't have numbers on them, just evenly spaces alternating colours. You could have each coloured section 1, 2 or 5 cm. You could make something similar yourself with a piece of dowel and some paint.

Comment by GlenM on May 30, 2011 at 10:47: You could carry a folding carpenters ruler. They are about 900 mm long but fold up into 1/4 of the length and you can buy plastic versions. Also carry a bulldog clip that you can use the clamp the two rulers together.

Comment by heather on May 30, 2011 at 14:22: Thanks GeorgeB, forgot about the folding carpenters ruler.

Comment by Michael Moses on June 3, 2011 at 10:49: Hi Heather, I havent forgotten this, i have a couple of designs at work, i'll get back to you next week.

Comment by heather on June 3, 2011 at 10:59: Michael, thanks. From the above photo, you can see what I do. Next week I will make a submission for funding for a suitable camera. Relying on another cyclist to bring their camera, while I hold the tape measure, has drawbacks.

Comment by heather on June 4, 2011 at 19:06: Today at Officeworks I bought a wooden ruler for only 81 cents. On one side it shows 5mm and 10mm intervals, with numbers for the latter. On the other side it shows 1mm intervals, with numbers every 10mm. Interestingly the 1mm markers have varying lengths, forming a zigzag pattern. There were 1m wooden rulers, but too long to carry on my bike. I thought wooden rulers were extinct. Not surprisingly no folding carpenter rules at Officeworks.

question for technically minded

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