Cartography

Virtual Layers and Bike Data

rjhale · May 14, 2019 · 1 Comment

To badly quote a Queen Song, “I like to ride my bicycle”. I’ve been trying to find new spots to ride. Of course being me I’m always debating things I can map while I’m out doing something.

This weekend I decided to map the Bike Share Program. It was raining so I went with a combination of windshield survey, bike riding, and internet searches to locate the Chattanooga’s Bike Share locations. I have a long standing history of being wrong about everything. When the bike share program started back in 2012 I shrugged and went “this won’t work” and 6 years later we’re got 40ish stations (I counted 40 and the internet tells me 41) and over 400 bikes. All the bike shares have a printed map and Chattanooga’s open data portal has a CSV of old bike locations.

Here are the 40 bike share locations in Chattanooga. I’m hoping to stick this in OSM and on the Open Data Site for Chattanooga.

I had read about Anita Graser’s Flow maps recently. One thing I notice when I’m out is how many places I see these bikes. Where do people come from and where do they go? Digging around on Chattanooga’s Open Data portal I found travel information that was slightly out of date but provided enough information to make this fun. The data gave me two things I needed: bike check-out locations and check-in locations. I know now people leave from Point A and end up at Point B.

Lets create a virtual layer from the table of information and the point layer. Trips being the table and Locations being the points:

SELECT StartStationID, EndStationID,
make_line(a.geometry, b.geometry)
FROM trips
JOIN locations a ON trips.StartStationID = a.id
JOIN locations b ON trips.EndStationID = b.id
WHERE a.id != b.id

I created what I can only describe as “hub lines” of the Bike System:

That doesn’t really tell me anything. It does show me the power of a virtual layer. A virtual layer is an area of QGIS I’ve not touched much – but in short it’s code tossed against a dataset and that code creates a new layer in QGIS. In this case I’m using functions in QGIS with some SQL code to render the lines. The lines act like physical data.

I refined the code a bit to only show one bike share. So where do people go that leave from the “main” spot (1299) at Outdoor Chattanooga?

Now that we’ve got fewer lines, things are more interesting. First off I don’t have data for all the stops – hence the dots with no lines. The second part I notice is some people go as far as they can go on a bike. They go to the farthest station. The Bike Share Program is “transportation” now on the same level as a bus but in just a smaller area.

Lets pick at it some more and do this:

Select EndStationID, count(*) from virtual layer group by EndStationID

That tells me the counts of where are people going from 1299. Not surprisingly from this location the #1 destination is this location (1299). People come back to where they rent the bike. The next two stops are “the scenic” bike share at 1319 and the bike share that connects to the free shuttle program at 1303.

The least used one is unsurprisingly 1329. That one is located not quite near the college campus and not quite near anything useful for day to day living. There’s really no reason to go there unless you’re lost or going to the Walker Theater for a concert. 1329 may be at the highest “spot” in the city or at least close to the highest (i.e. you have to ride uphill to get there from anywhere).

My next big question: Is it all connected with bike lanes? That data doesn’t really exist except within OpenStreetMap…and it’s outdated. It may exist somewhere in the city but I’m not sure where. My next mapping fun is finding a source of bike lanes for the city. I will probably make my own.

So what did we learn?

If you come to Chattanooga use the Bike Share (and wear a Helmet)
Virtual layers are pretty powerful and I really only did one thing – but it was a powerful one thing.
OpenData for your city is your friend. I will most likely hassle someone for an updated CSV for the city bike share program.

Go out and make a map….and ride your bike.

FOSS4GNA 2016 – First Post

rjhale · May 8, 2016 ·

It’s over.

As one friend pointed out there are something like 4 stages of conference attendance:

Go for the Tech
Go for the Friends
Go for Free Beer
You Stop Going

On most everything I’m at 4. It takes a lot to drag me to a conference these days. I think my most attended conference is the Georgia URISA Conference. I’ve made three FOSS4G Conferences. For FOSS4G events I’m still at a 1 and 2.

There’s going to be several blog posts over the next few days on the conference. I can’t cram all my thoughts into one post. Plus my posts have been getting longer and longer and I really want to shorten them up a bit.

I’ve made the conferences in 2013, 2015, and 2016. Each one gets a little bit bigger…..BUT – each one has the same community feel I’ve missed elsewhere and enjoy. It really doesn’t matter who is the super star rolling into this conference – you’re going to have the same good group of people finely arrayed from business casual to “Well Day 3 for these Cargo pants”. You have people who really get don’t enjoy crowds and then you have the people who can command a room full of people. This conference accepts all kinds and it’s nice. It’s refreshing. It’s the way GIS should be.

We were somewhere around 550 strong for FOSS4GNA – which if you noticed there was also the ESRI SERUG or whatever conference running at the same time during this event. Overall – didn’t hurt us a bit. In fact – ESRI – please plan competing ones from here on out. It actually may have helped.

If you haven’t been to a FOSS4G Event you should go. This is coming from a guy who is at a 4 for everything. You will meet friends, you’ll learn something, you will walk away refreshed (and a little tired).

Like I said – more posts coming shortly. This was my get up and “stretch and warm up” post for the rest of this week.

Just in case you’re debating going to something:

Map Competition for Georgia Students

rjhale · Apr 20, 2016 ·

…and from Georgia URISA:

Hello Students!

Announcing our

“Online Map Competition”

This map competition it is an opportunity for Georgia University/College students to share their best maps with others who appreciate quality cartography, innovation and finally get recognition for their talents.

This is an online competition. All maps/poster and links need to be submitted by midnight of May 10^thto urisaonlinemapcompetition@gmail.com with a minimum half a page statement that provides context of the submission, i.e. its purpose, how it may be used, how it was created etc…, and a cover page that will include:

Student information, including name, address, phone number, email address.
Degree program (e.g., M.A.), cartography/GIS instructor’s name.
Graduation Date
Institutional affiliation

Maps will be judged based on the following:

Standard Map Elements: Title, legend, scale etc: 15 points
Balance and Layout: Does map appear well-balanced to the eye? Are some areas of the map blank while other areas are crowded: 10 points
Drafting Technical Quality: Technical involvement; difficulties: 20 points
Detail Thoroughness: Is there too little detail? Is there too much detail? Does it extend into every passage? Is it consistent throughout the entire map? Is the detail easy to understand or is it confusing? Does the detail match the legend or the list of symbols? What would be the use of the map? Does the map show the purpose: 15 points
Visual Impact: Does the cartography make the subject interesting or boring? Overall, does the map look good: 20 points
Innovations, new methods which enhance the understanding of the map: 20 points

100 points is a maximum that student can acquire based on above requirements.

First, second and third place will receive a prize. Prizes to be announced soon! The rest of the participants will get recognition in the URISA newsletter and “swag.”

Maps need to be submitted by Midnight of May 10^th to urisaonlinemapcompetition@gmail.com, confirmation email will be an indication of the submission.

QGIS: The Label toolbar

rjhale · Apr 4, 2016 ·

You’re sitting in a class…..back up – You’re teaching a class and and someone goes “Hey – there’s this QGIS Label Toolbar. How do it work?”.

I’m probably better at making a map than I believe. I really don’t enjoy it because with every map Green was always a problem. “Can you make this green ‘greener’?”. I would get upset and go “OK” and immediately make it too green. Way back in my career I was working on a Spill Plan Prevention Control and Countermeasures map (I think that’s SPCC). This map was all manual back in the day. We had a plan to make it “digital”. So we scanned a photo (and didn’t georeference it) and started laying out ArcINFO Annotation on it. At some point we scanned another map and had to move everything (not georeferenced) again. Then at some point we decided georeferencing the map was a good idea so I had to move all the annotation. Again. Anytime you say “label this feature” I break out in a sweat to this day.

So I sat this weekend with the whole goal of making the QGIS Label Toolbar Active. The best I could do was this:

I finally “Read the Manual” and found that the label toolbar is Attribute based. So if I add some Attributes to my data layer:

x – decimal number – Length 12 Precision 3
y – decimal number – Length 12 Precision 3
rotation – decimal number – Length 12 Precision 3
visibility – integer – Length 1

…..and then I assign those attributes to the label properties:

…..and then I edit my layer:

I can now move my labeling all over the place to make a better map. I can turn labels off. I can rotate the labels. Of course I’m not even discussing the Rule based labeling and all the joy you can have there.

Anyway – I left a tutorial I need to clean up a bit over HERE that should at least get you started.

FOSS4GNA 2016 Program

rjhale · Feb 29, 2016 ·

Emails are flying so I wanted to throw something up here

Confession: I’m on the conference committee. The final count came down to these numbers: 93 full talks, 36 half talks, 10 workshops, and 3 keynotes. You may look at this and go “OMG they are going to be talking about how to github a geojson raster into the cloud using geojava.node.whatmacallit and this is going to be nothing but confusing”

To randomly pick 5 talks:

Hiroshima Archive: The goal of the “Hiroshima Archive” is to ensure that future generations will be able to learn the true cost of atomic warfare. Using Cesium, the archive is able to provide a personalized experience. A user could be viewing a 1945 map while browsing survivors’ accounts and photos. They could then choose to switch to modern aerial photography to see how the location has changed since.

Processing Raster Data for Online Use: Have you seen georeferenced historical maps online that just look…fuzzy? That’s what we started with at the Emory Center for Digital Scholarship, and we would like to share the steps we’ve found to get clear, legible, zoomable map overlays.

Cartography with InkScape: Sometimes your map needs a little extra polish. In this talk, I will outline my workflow for bringing maps from QGIS into Inkscape and exporting to commonly used formats to produces a finished professional-quality map. It will include “do’s” and “don’ts” to help you develop your own workflow and avoid common pitfalls, as well as some features unique to Inkscape such as filters.

PostGIS Spatial Tricks: This talk will showcase spatial feats you can do with PostGIS Special focus will be given to features new in PostGIS 2.2 and upcoming PostGIS 2.3.

Precision Ag and Open Spatial Technologies: Autonomous Vehicles, Drones and Data Driven decisions happening on a sub inch level. A city of the future? No, a farm today. Come find out the current Precision Agricultural techniques for data collection, analysis and dissimulation and where FOSS4G tech plays a key role. From harvesting millions of data points generated from every vehicle on the farm, to the corporate dashboard and reports, FOSS4G plays a role.

State of QGIS: State of QGIS reviews new and noteworthy features for the QGIS project. This talk will cover both Desktop and Server components from version 2.14 just released by the community.

So if you’ve never been to one of these things – that’s some of the crazy good talks you’ll see. Even if you’re all ESRI all Day this is good information. I know we are going up against the old ESRI SERUG conference – but I think as far as pushing the envelope of technical talks have everyone else beat.

Good People Come to Raleigh!

Cartography

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