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I bike to school every morning. I have 3 different routes to choose from each morning and
afternoon, all of which cross this one drainage ditch at some point. I did some research and I
found out it was called the Permanente Diversion Canal. It’s hard to describe what the area
looks like with words, so here is a map.
(Justin Kong 12.22.19)
The blue on the left is Permanente Creek, and the blue on the right is Stevens Creek. The
yellow in between is the diversion canal, and the black lines are the three crossings I use.
I learned that when Permanente Creek starts going through neighborhoods, it’s just a tiny dirt
ditch without flood protection. The diversion canal is surrounded by cement, and it looks like it
can take a huge amount of water. Here are some photos of the canal I took over the duration of
last year.
(Justin Kong 2.1.19-6.8.19)
One thing that really fascinated me was the start and end of the canal. I knew the end was at
Stevens Creek just East of highway 85, but I did not know where the start was. I wanted to see
this place, but I could not because it’s purposefully blocked off from the public. I found a picture
of the end on Wikipedia, and based on the graffiti, it might not be the safest place to go to
because of the people who spend time there.
I did find out I could get to the start of the canal, sort of. It’s not exactly by a road, but it’s visible
if you peer through a fence.
(Justin Kong 6.8.19)
Back in June, I biked to the road right by the start and I looked through the fence. There’s this
really weird door mechanism that controls which way the water goes, and it has been closed
(directing water to the canal) every time I’ve passed by.
In Heritage Oaks Park, there’s a place where you can walk right up to the creek. This park is
less than half a mile to the start of the canal. I went there last month with a couple friends, but
we couldn’t go into the creek bed because it had just rained and the current seemed pretty
strong. I thought that park (it’s the green one on the above map that says “Coach Ken Soccer
Academy”) was fascinating since it was right before a natural river entered a man made canal
that controls its flow and path.
(Justin Kong 12.22.19)
One other place where you can cross the canal is at the back of Blach Intermediate School. The
entirety of the southern boundary of the school is the canal, which makes it one of the few
places you can walk along it. There’s also one footbridge that connects it to Altamead Drive and
Carmel Terrace, which was pretty cool to walk across. I wonder if any of the students at that
school have ever been fascinated by this canal. I always thought my neighborhood and city
were kinda boring, but there are little details like the canal that just need to be discovered.


I did not see this until now, but my project got featured on GIS Lounge on Twitter, and I thought that was pretty cool. Even though I didn't make the animations myself, the red is data that I created.



Today was GISDay at Stanford, and I'm proud to say I got the opportunity to present my project on digitizing OSS maps!


Here are my slides and their accompanying notes.


The Office of Strategic Services (OSS) was an American intelligence agency founded in 1942 with the purpose of gaining and processing intelligence from the Axis Powers. Along with collecting intelligence, they often supported anti German and anti-Japanese resistance forces. They did a very good job of explaining the German war effort to the public, and one way they did was through making this collection of maps. Before its end in 1945, the agency collected lots of data, including maps of Axis owned land. 


The maps

In WWII, the OSS made these maps weekly with an intent to inform the American public of the war fronts in Europe. There are two scales, one to 38 thousand and one to 69 thousand. Those numbers basically mean one inch on the map is equivalent to 69,000 inches on the ground. In 1944 when the fronts were further out (in Russia and northwestern France), one to 69 thousand was used because it covered everything at the time. The map on the right shows this in the Balkans, where we can see pockets of land taken by the allies. In the one 38 thousand maps, all the action is centered on Germany, which is why the OSS zoomed it in.


Digitization Process

Some of you know how to digitize by entering edit mode, and then drawing polygons over the scanned map.  This video shows how I digitized polygons, one at a time, until they were all complete. The process included entering edit mode and clicking and dragging to make shapes on the map. Once I finished drawing each polygon, I added a couple attributes to them so each polygon is identifiable. Their type (current, advance) was entered. The purple advances represent the new acquired land each week while the green shows land that the allies already owned. Each polygon was given a week so they would be sorted together by date. 


A challenge I encountered was making sure the advance polygons matched exactly with the current polygons. Manually each vertex would take forever, and I still wouldn’t be done digitizing if I did it that way. Instead, I used the trace feature of the editor mode which let me move the mouse along the edge of a current polygon, and it would use it as one of the edges of the advance polygon. This process not only saves time and work, it also ensures precision and accuracy.


The Advantages of Digitized Data

So what makes all those hours of digitizing worthwhile? 

  • More efficient: it’s a lot more easy and convenient to access a digitized copy of map (or any document) because it requires much less manual searching
  • Duplicatable: multiple copies can be made and shared whereas a physical piece of paper can only be in one place at once
  • Preservable: a scanned map will last forever, where as a paper map degrades each time someone touches it
  • Easy to work with: you can easily pull a digitized polygon from a data set and use it for your projects. While scanned maps retain the valuable information, there isn’t much to be done with them from a data analysis standpoint. You can also zoom it in and out easily. 
  • Detailed: a paper map will never be as high quality as a digitized map where you can zoom in to infinitely large amounts.
  • Machine learning: putting digitized points from OpenStreetMap into a machine learning algorithm can make data creation a lot faster and decrease the amount of manual labor needed






I'm in my high school's marching band, and I've been keeping track my dots since my first year. (Dots are coordinates on a field, they tell you where to be and how long it takes to get there). Putting my path onto a map is pretty easy, it's just drawing lines on a map. I've been using Google My Maps to accomplish this, and here it is.


As part of a presentation that I'm gonna give next month, I needed to do a tutorial on using Esri Story Maps. In the tutorial, my task was to take a couple images along with their metadata and put them onto a map. Considering I had already been given the latitude and longitude, this was not too challenging. I used ArcGIS Online to place all of them on a map and customize each pop up. One thing I see being a problem is coming up with stuff to write about. This time was fine because the things to say came in the tutorial package, but it will be pretty challenging when I make the digitized OSS maps into a story map because I'll need to write stuff up from scratch.

As for the story map builder interface, I found it kind of confusing. I couldn't find a way to put different templates together on the same story map. For example, I wanted to have one map journal (which worked fine), but I could not find a way to add a cascade box after the map journal. I saw this on another story map I was reading, so I know it is possible, just that I can't find out how. Another thing is importing images. The platform has a 20 MB limit, and even then, you can't get the image to zoom in as you scroll down. There's gotta be a way to do this.