How The Heck Does GPS Work?

Good, albeit a little nerdy: How The Heck Does GPS Work?

A Projection Joke!

GPX to 3D Storymap

This is pretty fun: Creating a 3D Race Report with ArcGIS StoryMaps

Couple of comments:

• No sure why it is not possible to add a GPX file directly to ArcGIS Online - that used to work just fine with the 'classic' Map Viewer.
• Maybe there's a way to do it, but when I import a GPX file into ArcGIS Pro I get the thousands of indiviudal points, not a nice polyline. Sure, I can convert that, but that's another step.
• Seems like you really should edit the GPX points first to remove any weird ones - that's tedious.

Need Contours?

Try Axis Map: https://contours.axismaps.com/#13/42.6111/-72.5949 (here centered around Greenfield, MA). A few comments:

• You need to set an appropriate contour interval for your overall topography.
• I can 'see' the label or roads - not sure what's happening here.
• Export as vector, image, or GeoJSON - great!

What precision do you need?

Great simple table showing the distance represented by decimal degrees - obviously this works anywhere for latitude, but is only correct for longitude at the equator because the line of longitude conerge towards the poles.

Source: https://community.esri.com/t5/education-blog/a-set-of-activities-for-teaching-core-content-from/ba-p/1139408 (Page 30)

Sea Level Rise: It's not that simple

Well, it is at the basic level: global warming = less glaciers & warmer oceans ==> sea level rise. But, there's more to that story.

• Sea level rise is so much more than melting ice (6:08 minutes)
• What is sea level? (3:25 minutes)

Strava Art

Strava Art is nothing new, but fun! 

ArcGIS Field Maps

ArcGIS Field Maps is the new mobile data collection app from Esri - basically replacing the old Collector app. It all seems to work just fine as one would expect, but unfortunately my iPhone is too old to run the app. Here are some resources:

• Try data collection in ArcGIS Field Maps (the full workflow)
• Create a map for data collection in Field Maps (this is a little tedious using feature layers)
• Configure maps for the field (this should be obvious: offline mapping and downloadable map areas)
• Take Your Web Maps Offline with ArcGIS Field Maps (detailed PDF)
• Introducing smart forms in ArcGIS Field Maps (seems cool)

Smartphones Kill Spatial Thinking

This is a great article: Smartphones and the Uncertain Future of 'Spatial Thinking'. Smartphones and the associated navigation apps prevent you from creating a mental map of your environment by giving you the perfect path on a tiny screen. But, perfect for whom? How you get from A to B is of great interest to someone!

So, basically, precisely what we think of generating this renewed interest spatial 'things' may ultimately kill spatial thinking and awareness.

Great quote: "Isn't it ironic: the easier it is for me to get where I'm going, the less I remember how I got there. As a conscious consumer of geographic information, should I be rationing my access to navigation tools—the mental equivalent of taking the stairs instead of taking the elevator?"

Great quote: "With their small screens and egocentric perspectives, mobile navigation systems function like blinders, reducing the landscape to the width of a street. They narrow the world."

Collector for ArcGIS: Capture High-Accuracy Data

Humboldt Glacier (Venezuela): Drone Videos

Here are three incredible drone videos by Helena Carpio of the Humboldt Glacier in late February 2018.

• https://youtu.be/cqHXK3v1WII
• https://youtu.be/t3xCB7k6aR4
• https://youtu.be/KLbO0eNE4aQ

Strava Global Heatmap

Very cool and useful for finding new trails: Strava Global Heatmap

How accurate is your drone survey?

Nice and informative post: How accurate is your drone survey?

UAV Mapping of Greenland Glacier

Here's another great example of a UAV used in glaciological research - all for under $2,000 and the authors provide a detailed description of their methods.

• Ryan et al. (2015): UAV photogrammetry and structure from motion to assess calving dynamics at Store Glacier, a large outlet draining the Greenland Ice Sheet.
• Skywalker X8 UAV airframe
• Ardupilot APM autopilot (open-source)
• Agisoft Photoscan Pro (for the 3D generation)

Jouvet et al. (2017) provided a more recent example using the same system and workflow to generate 10 cm orthoimages of the Bowdoin Glacier in Greenland.

Ryan et al. (2014, their Figure 2)

CalTopo

CalTopo is a great tool to quickly display topographic maps, mark routes, get elevation profiles, and even add your own data (as GPX or KML).

Smartphone GPS Accuracy inside an Urban Jungle

You can read the entire post How accurate is your smartphone’s GPS in an urban jungle? or even the underlying study, but all you really need to know is about 90 feet (on average).

2 May 2000

GPS pre/post 2 May 2000

This seems so long ago...but before 2 May 2000 the US artificially degraded GPS accuracy in what was called Selective Availability. Below are two nice plots before and after (more here):

GPS Radio Occultation

For GPS users the atmosphere introduces errors, but someone's errors are other people's treasure: weather forecasting using GPS radio occultation and CubeSats, in-essence a new way to get massive amounts of atmospheric profiles from all over the world.

Shifted Maps

The Quantified Self movement has been around for a while now, but lately has exploded with the advent of inexpensive 'fitness' trackers that everyone seems to be wearing on their wrists these days. Of course, you can also use your smartphone with the Moves app and then visualize the the collected data using Shifted Maps.