Long = X, Lat = Y – Free Illustration Included


Feel free to use this everywhere. Print it out and hang it on your wall.

My biggest geospatial pet peeve is when people confuse the relationship between x/y and lat/long. I believe this is a fundamental concept in geography and I am here to reintroduce you to math you probably learned in elementary school (middle school maybe?).  If you already know the proper x/y-long/lat relationship then you can skip the rest.

First, let’s review the Cartesian coordinate system.  The X axis is the horizontal plane and the Y axis is the vertical plane. Two dimensional.  Pretty simple.

Now, let’s look at latitude and longitude. Latitude measures angular distance from the equator to a point north or south of the equator. While longitude is an angular measure of east/west from the Prime Meridian.

Now this is the important part.

  • Latitude values increase or decrease along the vertical axis, the Y axis.
  • Longitude changes value along the horizontal access, the X axis.

Easy.  X = Longitude, Y = Latitude.  Now you will no longer be confused when calculating centroids or setting webmap coordinates.

Happy mapping!


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I’m Back!

It has been a long time since I put GISDoctor.com into sleep mode. I haven’t posted anything here since 2014 and I have actually culled material from the site.

I did this for a couple reasons.  I was busy with life and I wasn’t all that excited about GIS. Things got a little stale for me. I was bored. I was having a little bit of a early-career crisis in my early 30s.

Professionally, my job has been excellent.  I am challenged with new problems everyday. But at the same time, the field of GIS wasn’t as awe inspiring for me as it was five or ten years ago (yes, I am old enough to say I have been doing this for over 10 years). So, I spent the past 18 months or so doing other stuff and not GIS blogging.

It was a great 18 months.

I’ve spent over a year being a content consumer.  I want to be a creator and contributor again.  I plan on posting with some relative frequency, tackling various technical and non-technical geo-topics – some short form and some long form.  I am not going to write exclusively about GIS, but rather the larger, more exciting geo-space.  There are so many amazing things happening right now across the geo-spectrum.  There are more people who consume maps, geospatial data and analysis, and location technology than ever before.  But, I see a big gap in the our space.  There are a relatively small number of people like me, the hardcore technical geo-nerd, but there countless casual geo-enthusiasts.  I hope to write about topics that the hardcore technical geo-nerds will appreciate and that casual geo-enthusiasts will understand and find interesting.   It’s probably a lofty goal, but I am up for the challenge.

It feels good to be back.



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Boston: America’s Most Active Geo-City!

That’s probably an overstatement.


The Boston geo-calendar is jammed packed with awesome stuff right now.  If you are in the area over the next few weeks, check out some of these upcoming events:

Now, I am sure I missed a few events.  If you know of an event that I missed tweet it out to @GISDoctor and I will make sure to add it to this list and retweet to my followers!

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