Hands On with Geospatial Technology
How to convert geographic coordinates
Navigation Tools 1.1
Requirements:
 Computer with internet connectivity
 Waypoint data to convert
 www.geocaching.com site
ASK
I have latitude and longitude coordinates for waypoints in two different geographic
coordinate formats! I want to add those waypoints to my map – but they need to be in
the same format. How do I convert the coordinates to the same format?
Three types of geographic coordinate formats
DD Decimal Degree – eg – 39.500
DMS Degrees Minutes Seconds – eg – 39 degrees 30 minutes 0 seconds
(looks like 39°30.0)
DM Decimal Minutes eg – 39 degrees 30.0 minutes
INVESTIGATE
Converting your waypoint data from Degrees Minutes Seconds (DMS) to Decimal
Degree (DD) format is easy and can be done automatically on the internet as shown in
the following directions. It may also be figured manually with this formula: (D + M/60
+ S/3600) It is suggested that you try both methods.
CREATE
Step 1. Go to www.geocaching.com which offers a quick conversion feature allowing
for easy data conversion into Decimal Degree (DD) coordinates.
Step 2. Log in (this is a safe site), enter your zip code and click “go”.
Step 3. A list of geocaches in your area will appear. Click and open any geocache on
the page.
Step 4. To access the conversion tool, look at the blue link next to the latitude and
longitude coordinates called, “Other Conversions”, and click on this.
Step 5. Screen 1 below shows that the current format is in Degrees and Minutes, but
you want Decimal Degrees. To convert to Decimal Degrees, open the drop-down box,
choose Decimal Degrees and then click “Change Waypoint”. The numbers shown
below are the latitude and longitude of the geocache opened earlier.
Screen 1
Hint: Remember to enter the data coordinates in their current format, and then in the
drop-down window to select the format you wish to change waypoint data.
Screen 2 shows the new coordinates, now in Decimal Degrees. Replace these
coordinates with your data, and follow the same path to convert.
Screen 2
REFLECT
Does this activity allow for easy conversion of geographic coordinate data?
Were you able to complete data in both the automatic conversion chart and manually by
the formula?
How can this activity help you in the future?
Related Weblink:
http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html
Authors: Barb Roberts, Youth Development Educator, University of Illinois Extension,
Lawrence/Richland Unit. and Dennis Bowman, Extension Educator, Crop Sciences,
University of Illinois Extension, Champaign Extension Center
Date: March 16, 2009
Sources: Dennis Bowman; Joseph Kerski, ESRI; Wikipedia Jan 2009
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