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Archive for the ‘FOSS4G Korea’ Category

Google Maps won’t help you much in Seoul…

Posted by smathermather on August 29, 2015

That could be my whole blog post. Just a PSA. Google Maps in Seoul is like Apple Maps was when they launched — dangerously inaccurate. *I don’t know what is helpful on iOS. I traveled last year with Android only, and my searches so far on iOS are coming up short.*

So what should you use? Anything OSM-based isn’t too bad. I really like OSMAnd. I haven’t done any deep analyses in this space, but OSMAnd has served me well. Also, you can record tracks, so if you see something wrong or out of date, OSMAnd will help you fix it in OpenStreetMap.

Icon for OSMAnd

I adore Seoul’s subway system. It’s considered one of the largest in the world,  ranks among the best, cleanest, etc.. Many stations are like 5 story malls that happen to have trains at the bottom; it’s really surreal. Oh, and for an English speaker it is not hard at all to navigate. Almost everything is in romanized characters / English + Korean, and the trains play nice sounding music as they approach.

It doesn’t hurt to have a good app, however. Subway Korea, though a little strange in interface is absolutely amazing once you use it. I say the interface is weird — it’s just transit graphic at a single static scale (it doesn’t change appearance as you zoom). But that graphic allows you to route between locations calculating train changes as necessary, let’s you optimize for time vs. number of train changes, and allows you to do routes by way of particular stops you may want to take on the way. It is great in large part because it’s designed with a deep understanding of how transit works and the kinds of questions people who don’t know the system need answers to. That’s a tall task. I can recall my first time navigating public transit in Boston, Cleveland, New York, DC, San Francisco, Portland, and Denver. Each of the above (even Portland!) was a little more difficult than Subway Korea and Seoul’s amazing wayfinding.

Icon for Subway Korea

Posted in Conference, Conferences, FOSS4G, FOSS4G Korea, Other | Tagged: , , , , | Leave a Comment »

Public Sector GIS done extraordinarily well

Posted by smathermather on September 28, 2014

Today I’ll highlight the work of Photo of Mr. Yu, B.J. Jang, and Stephen Mather at Smart GeoSpatial Expo 2014Mr. Byeong-Hyeok Yu, one of two GIS people at Korea National Park Service (KNPS). The other GIS person is (if memory serves) in the research branch of that institution.

I’ll highlight a few of Mr. Yu’s projects. To start with, we have the classic natural resource management projects — you remember — those analyses that you did in your college GIS programs that were the promise of what was to come, what you were to do in a career of GIS? Ya. He gets to do those for his real job.endangered_species_mapping

In fairness, based on all he does, I suspect he doesn’t sleep many hours each night.

What else though — that is what you’d hope a parks GIS guy would do. Mr. Yu has piloted KNPS’s drone program, flying a variety of sites which require high resolution aerial imagery with 8 rotor UAS’s.


One of the great gaps in understanding natural resource management is getting both synoptic and detailed spatially explicit information. Drones promise to do both in projects from a few acres to adrones1

few square miles. It’s really refreshing to see KNPS leading the way in this category.


There are just two more projects I want to touch on. The first, like drones, is address the question of how do we, as managers of parks, steward high resolution info, in this case both for operations and park users. To this end, Mr. Yu has a small army of park rangers wandering around with backpack camera units mapping out trail view (like streetview) imagery for Naver Daum, (one of Korea’s Google equivalents). I like projects like this, as they leverage existing work within the organization (a small army of park rangers hiking the trails of KNPS and interacting with and helping visitors), and external partnership, in this case Naver to achieve an exceedingly useful product that has the following benefits: documentation of the state KNPS trail system (these data become historical some day), addresses recreational needs and questions of the public, and likely aids in operational and planning questions that would be difficult to address otherwise. (As a side note, for application in the US, I’d be interested in the licensing of the resultant data — I’m an advocate of such data being as liberally licensed as possible, something difficult to accomplish with some of our native tech giants).

OK.  One last project. My organization has been working for a few years on really great online mapping products to ensure that we engage people on the platforms that they occupy, i.e. the physical world, and that embodied in their phone. It is a project of which I am most proud. Not surprisingly, I’m going to steal some ideas from KNPS equivalent. Many ideas, actually… . Mr. Yu has initiated something similar (and in usual fashion, of highest quality) in rolling KNPS native trails app (shown here on a Samsung phone 🙂


This app serves two purposes.

The first is that engagement piece I reference above — the app is an exercise in how to use the smart phone as a platform for engaging, educating, and making comfortable park users.

The second purpose is simple. The app becomes a tool for connecting injured hikers with rescue personnel. To this end, it has already been used twice.


So. Is this public sector GIS as you think of it? Bravo Mr. Yu. For the record, Mr. Byeong-Hyeok Yu has been in his position 3 Years.

Posted in FOSS4G Korea | Tagged: | 3 Comments »

FOSS as Folk

Posted by smathermather on September 10, 2014

Let us expand a bit on the theme of Free and Open Source Software as _Folk_ software development, i. e. of the people, for the people, and by the people. When I put together my presentation for FOSS4G Korea 2014, I had elements of this theme in it. I expected I would talk about the relationship between governance and open source software in the context of legitimacy — that one informs the legitimacy of the other, as both operate in that shared space we might call commons and derive their legitimacy from that commons.

As I spoke with Sanghee Shin and other OSGeo folks when I arrived, the concepts really crystalized: Free and Open Source Software is folk software, enabled to be built due to the connectivity available by the medium of the internet, by creators with common purpose and common love. And as _folk_ software, not only will development and support of Free and Open Source Geospatial sofware lend legitimacy to the South Korea’s central government’s initiative in software, but that as commons-based peer production, open source software becomes an open expression of Korean culture, Korean ingenuity, and Korea’s contribution to the broader GeoSpatial world.

From the outset, what I was attempting with the speech was to combine Paul Ramsey’s diagram for commons-based peer production (Love of common interest + inexpensive tools for production + internet = commons-based peer production, i.e. Wikipedia, OpenStreetMap, FOSS software, etc.) with Kate Chapman’s call to action: Geo for All, a call for the widening and deepening of the pool of contributors and users of GeoSpatial data and software. The concept of FOSS as Folk happens to do just this thing, and hints at some of the challenges before us in making FOSS accessible.

But, the question of _folk_ explicitly gives us additional conditions and context for creating an inclusive community. This touches back to Kate Chapman’s call for geo4all — understanding FOSS as Folk explicitly calls us to balance simplicity and elaborateness (석가탑 다보탑), and thus helps us be inclusive, but also gives us traditions and context for implementation.

Let us tie this all together in a sentence or two: FOSS is Folk Software, Folk has legitimacy through inclusive process similar to democratic society, and Folk software can draw on other Folk traditions to achieve the balance of simplicity and elaborativeness that results in software and tools that are inclusive and effective. Finally, looking to Governance and Open Source, the work of South Korea in supporting FOSS for geospatial and initiatives like Code for America, FOSS and democratic processes can draw legitimacy from each other by resourcing the same Commons space.


Posted in Conferences, FOSS4G, FOSS4G 2014, FOSS4G Korea | Tagged: , , | 2 Comments »

Bukhansan National Park, Seoul, Pt Two — on to Dobongsan Mountain

Posted by smathermather on September 5, 2014

Fewer words, more pictures this time. On to Dobongsan Mountain. This time, I went through a different entrance just to the north and east of the previous entrance.

DSC05134 DSC05135 DSC05136 DSC05140 DSC05144 DSC05164 DSC05167 DSC05169 DSC05235 DSC05237 DSC05239 DSC05263 DSC05279 DSC05285

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Bukhansan National Park, Seoul, Pt Two — off to the base of Dobongsan Mountain

Posted by smathermather on September 4, 2014

In my previous post on Bukhansan National Park, I had the blessings of a guide, ilJumun Jingwansa, who is a KNPS ranger. My second time in the National Park, I took a subway train by myself to explore. This was a quick hike to familiarize myself with getting to the mountain, rather than an in depth exploration.

Photo along Teheran-ro in Gangam District, Seoul

Photo along Teheran-ro in Gangam District, Seoul

Photo from train while crossing the Han River.

Photo from train while crossing the Han River.

I took a train from my hotel in the Gangnam district to the Dobong Station, which is the closest subway station to Bukhansan National Park.

Photo near Dobong Station

Photo near Dobong Station

One thing that I noticed most everywhere in Seoul was the use of the small narrow spaces along rivers, under expressways, and other nooks and crannies that serve as linear parks with multi-purpose trails connecting them. Next time I am there, I hope to rent a bike and do some serious exploration of these,

From Dobong Station, I wandered up a stream along a multi-purpose trail, passed a narrow band of agriculture, to the foot of the mountain.

This adventure ended up being more about the edges of the city, and how they feather into the edges of the National Park and less about the National Park itself. But, it did give me the confidence to navigate to the Bukhansan and to the base of Dobongsan Mountain.


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Bukhansan National Park, Seoul

Posted by smathermather on September 4, 2014

For all the time I spent in the city of Seoul, I was able to make three trips into Bukhansan National Park which is partially inside the boundary of the city. It can be both a remote space, and a space overrun by visitors from the cities around. Seoul contains more the 10 million residents, and the metropolitan region is the third largest in the world with more than 25 million.snapshot of bing map of Bukhansan National Park

The park itself is two mountains, Bukhansan Mountain itself and Dobongsan Mountain, although there are many named peaks along the two ridges. The valley containing the Bukhansanseong fortress divides the two mountains, and is said, due to natural springs, to have had the capacity to hold 50,000 people.

5 Ridges as viewed from the road at the southern end of Bukhansan National Park

Credit: ilJumun Jingwansa

IlJumun Jingwansa was my guide on the south end of Bukhansan Mountain (any history or natural history I get right is due to him — anything wrong is mine). We hiked up onto the side of the Bukhansan of the National Park, between Hyangnobong and Jokduribong peaks. Jingwansa was incredibly knowledgeable about the cultural and natural history, and as we walked and I peppered him with questions which he answered, for biological questions looking up English name equivalents of Latin names where they existed.

Image of side of mountain with Jingwansa

We saw two oaks along the way, Quercus acutissima and Quercus mongolica.

Image of Quercus acutissima acorn

We talked about crows and wildfires, trails, and the difficulty of maintaining the natural resources of a park under the constraints of heavy use and a loving public.

These mountains are made of granite, hard, and warm, and dry on the days I saw them. And they overlook the cities around them. It was here that first understood how mountainous Korea is, and something of the relationship between the Korea people, their mountains and their sea. The Korea National Park Service (KNPS) logo reflects this:



More soon… .

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And then Steve gets all sentimental…

Posted by smathermather on September 2, 2014

for sweetness in `ls *sappy*`;

It is bittersweet as I leave you, Korea. I did not intend to stay this long, so I do miss my family dearly. As my son started kindergarten, I flew to you, and you welcomed me. You astonished me with hospitality, humor, understanding, and the deep beauty of your people, your language, your Seoul, and your mountains. Thank you for the time and conversation with Tongju Dongjoo who offered me grapes and words on Dobong mountain, for ‘Jim’ who fed me rice cakes, shared his spot in the creek for cooling off hot and tired feet in the valley



Thank you for the atmospheric scientist and programmer whose hospitality and grace were unmatched. May her purpose and direction continue to unfold before her.

Thanks for the statistician turned Open Source GIS person who listened, translated, and understood.


And for the centurion who I will see again soon.


It was with these three I ate and drank, talked to at length, and with whom I experienced that elevated hospitality you, Korea, are known for.  These three laughed and cheered as I ate the more difficult seafood (sea worms and urchin shell and all, live squid on ice…) , taught me the fine ceremonies of soju, and so very quickly I came to count as friends.

And so, as I long to be home with my loving family, the parting is bitter and sweet. Is it also sour and salty and umami, or would that strain the metaphor too far?


I hope not. Until next time…


Posted in Conferences, FOSS4G Korea | 1 Comment »

FOSS4G Korea 2014, poor GPS photos, and mapillary (part 2 of n)

Posted by smathermather on September 2, 2014

A classic and age old problem in GPS is collecting potentially wonderful data in the field, getting back the office, and realizing a lot of manual scrubbing, data massaging, and other such careful work will need to be done to make the GPS data useful and meaningful. This assumes we can even meaningfully correct it at all.

This is true too (maybe especially) for GPS enabled cameras in canyons and urban canyons. This is a problem we started to explore in

Let’s return to the problem briefly. Were the GPS readings to be consistent and accurate, we should see a relatively straight line of points as the photos were taken along the length of sidewalk on Teheran-Ro in the Gangnam District of Seoul

Figure of raw data points showing anything other than a straight line

In addition to not looking straight, though it is supposed to follow a road, we previously demonstrated that there are a lot of points duplicated where, presumably, the camera was using cached GPS data rather than the latest available at the time of the photo. We can see this density of overlapping points even more clearly using the heatmap tool in QGIS:

Heatmap showing clumping of data points

The clump of red shows a clear issue of overlapping points. As these points are the GPS positions of photographs, we can match features between photographs (using structure from motion) to map out the relative location of these photos to each other. The points in the below figure show the matched points in 3 or more photos, the blue shapes represent camera positions within the scene.

Image of sparse point cloud and relative camera positions

If we look at just the camera locations on a map, we see something like the following:

Figure of camera center points in relative space

For the astute student however, it should not be surprising that the coordinates of these points are not recognizable as any known coordinate system. For example let’s view the X, Y, and Z of the first three points:

id	X	Y	Z
1	-0.357585	-0.390081	-3.48026
2	-0.326079	-0.367529	-3.24815
3	-0.295885	-0.348935	-2.98469
4	-0.272306	-0.334949	-2.79409

This means we require some equation to convert between our unreferenced (but consistent) data to a known coordinate system. To build this equation, we just need to know four things about our data with some certainty — the start point and end point X and Y positions. We will ignore Z for this exercise.

Point 1:
X-Local: -0.357585
X-KUCS: 958632.326047712
Y-Local: 1.29161
Y-KUCS: 958744.221397964

If we remember our trigonometry (or google our trigonometry…) then we’ll be able to solve for our X and Y values independently. For example for X:

X1 = 67.8485 * X + 958657

With that and our Y equation:

Y1 = 27.2400 * Y + 19444469

Now we can transform our local coordinates into the Korean 2000 Unified Coordinate system, and get a much nicer result:

Figure showing corrected camera position points

If we perform a heat map on this output, we’ll see that we have spread out our duplicate geometries to their correct, non-overlapping spacing:

Figure showing corrected camera position heat map

Whew! Now to write some code which does this for us… .

Oh, wait! We forgot the final test. How do they look together (pre and post transformed — post transformed as stars of course):
Pre and post transformed points compared in single figure

But, as we know Google (or in the case of Korea, Naver) is the all knowing authority on where thing are. How does this bear out against satellite imagery?:

Pre and post transformed points compared in single figure with aerial for comparison

Woah! That works for me. Notice, we can even see where I walked a bit to the left side at intersections to move around people and trees.

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FOSS4G Korea 2014 and the tale of the three Stephens

Posted by smathermather on August 31, 2014

Much is going on in Korea. It is and will be a place to watch for Open Source GeoSpatial, with the likes of Sanghee Shin and all his local chapter OSGeo compadres leading the charge. FOSS4G Korea was part of Smart Geospatial Expo 2014 this year, and during the expo, Sanghee was awarded a prize from the South Korean president for his work in promoting Open Source geospatial technologies. To hear Sanghee explain it, Korea is very much interested in growing its industries through the minds of their people. The great successes of South Korea in the recent past have not been dependent upon the natural resources of Korea, but the intellectual capital of firms such as LG and Samsung. With this in mind, Korea wants to grow it’s software industries from native seed. Sponsorship of Open Source GeoSpatial technologies will be part of this initiative. It seems that they have the talent, the energy, the love of topic, and now the financial resources to start leading. This will be really fun to watch.

But, for this post, I want to focus on the tale of three Stephens, perhaps an echo of narcissism, but an interesting filter for our post today. Not long before I left for this trip, I contacted Sanghee to ask if there were any parks + GIS folks I could connect with while here to talk. Photo of Mr. Yu, B.J. Jang, and Stephen Mather at Smart GeoSpatial Expo 2014 It turns out, Mr. Byeong-hyeok Yu was presenting at FOSS4G Korea on the use of QGIS for remote sensing for the Korean National Park Service. Mr. Yu is one of two GIS people working at KNPS, the other is with their research branch. Mr. Yu was good enough to invite me to headquarters, give me the overview on smartphone apps, QGIS analyses, UAS (drone) flight work, Google StreetView like trail work (in partnership with Naver maps, I believe), and other cutting edge initiatives they are working on. What FOSSGIS has enabled under Mr. Yu’s stewardship is the ability for not just Mr. Yu to do GIS, but also for him to democratize the process and allow a few hundred of KNPS park rangers to use QGIS on their desktops as well as to be the bearers of the equipment for the trail camera project. I like to think of Mr. Yu as a more bright and energetic version of me. After all, he is a FOSS4Geospatial parks guy. So, we’ll call Mr. Yu Stephen Mather number 2 (I did call this narcissism, right).

But here’s the real reason for the tale of three Stephens. Whoever has studied the history of the National Park Service in the US knows of Stephen Tyng Mather, the borax mining magnate and essential founder of the National Park System, who oversaw the development of 20 National Parks in his short tenure. While visiting the headquarters of KNPS, I was given the privilege of an audience and traditional Korean tea ceremony with tireless servant, Stephen Tyng Mather equivalent, and employee number 1 of Korea NPS, Mr. Young-Deck Park. Mr. Park has seen the KNPS from an idea to 21 parks covering more than 3-percent of Korea’s land area (more than 6% if you include the ocean refuges). In short, I was in the presence of a parks visionary and giant. Stephen Mather number 3. I won’t lie. I had to hold back tears. Oh, and the green tea was the best I have ever had.

To close this post, I’ll show you a view from KNPS’ most beloved, and least remote National Park — Bukhansan, which sits north of the Blue House (Korea’s equivalent of our White House) and partially inside the city of Seoul. At 11 million visitors a year and about 19,000 acres, it is quite popular. I hiked one of the ridges with one of their rangers. More on that in another post.

A view from Bukhansan National Park over Seoul

Posted in Conference, Conferences, FOSS4G Korea | Tagged: , , , , | 1 Comment »

FOSS4G Korea 2014, poor GPS photos, and mapillary

Posted by smathermather on August 31, 2014

As I have been moving around, whether traveling to Seoul or within Seoul, I have taken a lot of pictures. Some have GPS and I’ve processed to sent to Mapillary, like a few hundred I took on a day wandering Seoul:

Screen shot of Mapillary overview of SeoulI’ve taken a lot of strange videos too. I took a couple videos of my feet in the subway train just to get the music that plays to notify passengers of an approaching stop. Walking around Bukhansan National Park, I have taken many sign pictures. As I work for a park district, how signage and wayfinding are handled here is facinating, both from what I can understand, i.e. choice of material, color, frequency, how the letters are carved, to those elements that I cannot yet understand, i.e. exactly how the Korean Language wayfinding portions work.

But mostly I have been cataloging as much as I can in order to give my children a sense and feel for the city. I am realizing this imperative has given me a child-like view of the city. (Of course, my enthusiasm for the mundane does get me the occasional funny look from locals… . But hey! What could feel more like home than people thinking I am a little strange.)

This blog wouldn’t be mine without a technical twist to the narrative, so let’s dive into some geographic problems worth solving: The camera I have has built in GPS and compass, which makes it seemingly ideal for mapillary uploads. Except the GPS isn’t that accurate, doesn’t always update from photo to photo, struggles in urban areas in general, etc. etc.. And so it is that I am working on a little solution for that problem. First let me illustrate the problem better.

A sanity check on the GPS of the data can easily be done in QGIS using the Photo2Shape plugin:

Screen snapshot of photo2shape plugin install screen

Screenshot of distribution of camera GPS points in QGIS

Let’s do two things to improve our map. For old-time sake, we’ll add a little red-dot-fever, and use one of the native tile maps, Naver, via the TMS for Korea plugin.

Naver map with photo locations overlayed as red dots

We can see our points are both unevenly distributed and somewhat clumped. How clumped? Well, according to my fellow GeoHipsters on twitter, hex bin maps so 2013, so instead we’ll just use some feature blending (multiply) plus low saturation on our red (i.e. use pink) to show intensity of overlap:

Capture of map showing overlap of points with saturation of color increasing where overlaps exist.

Ok, that’s a lot of overlaps for pictures that were taken in a straight line series. Also, note the line isn’t so straight. Yes, I was sober. No, not even with soju can I walk though so many buildings.

Like all problems when I’m obsessed with a particular technology: “The solution here is to use <particular technology with which I am currently obsessed>”. In this case, we substitute <particular technology with which I am currently obsessed> with ‘Structure from Motion’ or OpenDroneMap. ODM would give us the correct relative locations of the original photos. Combined with the absolute locations (as bad as they are) perhaps we could get a better estimate. Here’s a start (confession — mocked up in Agisoft Photoscan. Sssh. Don’t tell) showing in blue the correct relative camera positions:

Image of sparse point cloud and relative camera positions

See how evenly spaced the camera positions are? You can also see the sparse point cloud which hints at the tall buildings of Gangnam and the trees in the boulevard.

  • Next step: Do this in OpenDroneMap.
  • Following Step: Find appropriate way to correlate with GPS positions.
  • Then: Correct model to match real world.
  • Finally: Update GPS ephemeris in original photos.

So, Korea has inspired another multi-part series. Stay tuned.

Posted in 3D, Analysis, Conference, Conferences, FOSS4G Korea | Tagged: , , , , | 2 Comments »