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Discussion: Laser rangefinder

in: Pink Socks

Sep 14, 2016 1:18 AM # 
Once you're recovered from SART, I'd be interested in learning a bit more about your rangefinder.

What model do you use? How often do you use it? Are there any interesting/fun non-mapping uses?

I've been curious about a laser rangefinder for mapping, but just not sure I'd use it.

I took a quick look at the SART maps. They look great. You do a much better job of drafting than I do. I also like some of your non-ISSOM mapping (like the court lines for tennis and bball courts and the thin white lines around individual trees).
Sep 14, 2016 6:21 PM # 
Pink Socks:
What model do you use?

It's this one.

How often do you use it?

For the maps that I've made/updated since I got it, I didn't use it at SPU, Gas Works, or UW. For the urban maps, the aerial photos are too good.

I used it at Carkeek Park, and I used it to finish up the last pocket of Shoreview Park that I never mapped last year. Basically, areas of wooded trail networks on slopes. Aerials aren't really useful. The LIDAR is from 2000 so it doesn't pick up trails. My GPS isn't super accurate due to the tree cover and slope. Also, my pace counting isn't consistent with the mix of slopes and stairs. I had hard time mapping the trails at Shoreview last year, so I figured that something like a rangefinder would help me out in nailing down the exact locations of trail junctions and such.

I mentioned in my other response to you about how it helped me nail down the location of a boulder I stumped upon at Carkeek at the end of an indistinct trail. I had a clear shot of some nearby houses, so I triangulated from them.

Are there any interesting/fun non-mapping uses?

I haven't found any yet, but who knows!

They look great. You do a much better job of drafting than I do.

Thanks! I'm a super-perfectionist when it comes to the urban maps, so my drafting is insanely clean.

I also like some of your non-ISSOM mapping (like the court lines for tennis and bball courts and the thin white lines around individual trees).

I've studied a lot of Vancouver maps and sprint maps in general, and I've cherry-picked a lot of things that I like. I really focus on making my maps legible (which is why I spend so much time on drafting). Legibility leads to things like white outlines around single tree symbols. Last year, when I mapped Woodland Park, I actually varied the size of the white circles underneath with the size of the tree canopy. I didn't do that on any of this year's new SART maps. In fact, I only used the small tree symbol for the three new SART maps. At SPU, this was basically for legibility: the larger tree symbol just took up too much space near other objects. At Gas Works, the map was so tiny and trees so close together that using the smaller symbol was the only one that would fit (I could have mapped more as Open Land with Scattered Trees, but I wanted more mapped point features in areas of the park that lacked them).

I find that tennis, basketball, and soccer field lines are really useful. It makes the map more accurate and accessible.

One thing that I've done on all of my maps is use different colors of pavement for vehicular areas and pedestrian areas. The Whistler Village map does this, and I found it pretty clever, and it's not exactly non-ISSOM (it's pretty vague here). I actually used three colors of pavement for North Seattle College in 2014 (my first professional map) because it really helps differentiate the multiple levels. North Seattle also has the weird not-quite-ISSOM interpretation of the passageway/tunnel symbol, but that's a special case.

Other non-ISSOM things from this year's SART maps: the olive green with black slash. I mapped Carkeek with basically olive green everywhere, so I needed a way to differentiate the off-limits forest with private land. Once I did this, it actually made sense to use this at SPU, to differentiate between landscaped areas and private residences.

The machinery in Gas Works Park. My original plan was to make the map at 1:4000 and include a 1:1000 inset map of the play barn. But I challenged myself to map the play barn at 1:4000, which was actually mostly possible. I mapped the machinery in the barn as buildings, but the building gray fill with black border wasn't working right, but when I switched to just building fill gray, it worked a lot better. The play barn also has a few vertical pipes, which I mapped as dots.. basically one stony ground dot in the building gray color. They are super tiny and not that visible on the map, but I think it's better to have them tiny than not at all. The Gas Works Park map doesn't use one single man-made X or O symbol in the urban area. They just take up too much spade and hinder legibility.
Sep 14, 2016 10:35 PM # 
Would you consider doing an OOM training course for COC? I have several maps started in my local area but have been frustrated at my drafting skills for trying to complete them efficiently. I'm good at other CAD software (primarily 3D) but 2D drafting in OOM has frustrated me. I'd love to get better at it.
Sep 15, 2016 6:25 PM # 
Pink Socks:
I would, Alex. You're not the first to ask this question, either.

At the CascadeOC AGM in September 2014, I did give a quickie presentation about mapping in OOM, but it was pretty quick.

I remember attending an OCAD mapping clinic that Eric led at Magnuson Park way back when (2007-2009-ish), but I didn't find it all that helpful because I wasn't actively mapping at the time and I forgot all of the shortcuts and tricks by the time I started mapping.

It might actually make more sense to work with smaller groups or individuals, because some people like you want to learn more about efficiency with drafting, but others want to know more about how to get started (bringing in templates at the right scale, etc), and others the basics of orienteering mapping (the symbols and how they are used, etc). I think it's hard to cover all of those bases adequately at one training course.

I still have trouble with georeferencing and such. I never know what grids and datums I should be using, so when I import LIDAR stuff, I always have to manually scale and rotate it a few degrees to get it to match the photos. I only have to do this once per map, so it's not that painful, but I wish I knew what I was doing a little better in this regard.

Anyway, perhaps we schedule to meet up after one of the WIOL meets this year for a training session?
Sep 15, 2016 10:33 PM # 
Yes I agree that focus on smaller groups probably is more productive. For me I would primarily be interested in:
-Drafting tips/tricks as well as best process (i.e. what do you draw first? what do you draw last? etc.).
-I would also be interested in learning about using LIDAR data since I have not done that before.
Keep in touch about scheduling something. The PNW winter is a perfect season for staying inside and drafting maps (maybe not for field-checking?). Maybe I can actually get a few maps done this winter?
Sep 16, 2016 2:51 AM # 
What to draw first?

Here is my process:
Building outlines based on reality
Then start fitting in all the associated canopies, ramps, stairs etc connected to the building.
I frequently push and shove the walls of the buildings around to make that stuff fit, but you have to pay attention to the relative alignment of the buildings at the same time.
Then I draw all the black outline edges defining pavement edges which breaks everything into chunks.
Then I fill in all the point features in each chunk.
Then I do the veg fills in each chunk.
Then I do the pavement fills.

Its not normally across the whole map in those stages, i.e. there will be bits and pieces that are totally done, and others that have made their way through the process to different stages. And its not a hard set of rules. When working on the building cruft a lot of times it is useful to start sketching in pavement edges for alignment and visual test fitting. So much of that is making it look good and right so you have to be constantly paying attention to path widths relative to other things etc.

I work in OCAD, and the most important tips I can give are to get very good with understanding how the curve tool works (never never never ever use the freehand tool), and getting used to the quirks of edge following when filling in area symbols. If you can conquer those, then you will be a better drafter than most even with no other skills.

I wish you were all in Boston and I would give you some GIS/projection/lidar lessons on how I use QGIS and GDAL/OGR to do my work.
Sep 16, 2016 2:54 AM # 
Also useful would be more teaching on how to do final map production and the process of getting proper files to a printer to achieve the results you want. My process is probably not one lots of people are going to use, involving a lot of illustrator work/skill, but I still think it would be good to at least expose more people to what goes on in this kind of work.
Sep 16, 2016 6:17 AM # 
Pink Socks:
Interesting. Thanks for sharing your process!

For urban maps, I usually always start with pavement edges and the bounds of the map (which are oftentimes on roads). In urban environments, the pavement edges usually lead straight into walls, fences, and building outlines, which are next, and this is where I have to fudge things a little bit if things are too narrow in real life to fit the minimum width required by the mapping standard.

With so much pavement edges mapped, that breaks down the map into chunks in between, so I usually work a chunk until I can't work it anymore. After the linear features are done, then it's point features, and finally area features. Vegetation fill is reliably the last thing I map. (That said, I do pavement fill in chunks as I go, because it's easy work when my brain needs a rest).

In OOM, I predominantly use the straight line tool and then convert to curves. It's a wonky way to do it, I know, but I find that OOM does a pretty good job of getting the curves I want, or maybe it's that I've learned how to draw sections of straight line that will get curves how I want. I've gotten pretty quick at doing it, regardless. Looking at Rex's UW map, he draws straight lines, too, and oftentimes he never converts them to curves. It looks sloppy when zoomed in, but at printing scale, it's barely noticeable.

I use the edge following shortcut a lot. OOM has a paintcan fill tool which fills in an area for you. It has some quirks on sharp corners that aren't perfect, so I use a mix of edge-following and paintcan. When I draw vegetation boundaries, I never use the fill symbols. I actually use one of the linear water features symbol as a "helper" symbol to draw all of the vegetation boundaries, then fill in those later with vegetation fill. (I realize that I have to do this extra step because I don't draw curves. With curves and edge following, you could draw area features in one step.)

Matthew Robbins cedar_creek has helped me out with getting LIDAR stuff into QGIS and how to generate contours, which was super helpful. For small 1:4000 maps, if there's any distortion, it's really small, because my manual method of scaling and rotating ever-so-slightly has always worked. But I understand that this could be a problem when I start mapping bigger areas.

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