Skip navigation
All Places > Esri Technical Support > Blog > Author: TJaiswal-esristaff
"Why does my profile graph show an elevation change of 11 feet over 1,111,111 feet?"

In general, profiles show the change in elevation of a surface along a line. They help to assess the difficulty of a trail for hiking or biking, or to evaluate the feasibility of placing a rail line along a given route.

A Profile Graph represents height on the Y axis and horizontal distance on the X axis. The unit of distance along the X axis depends upon the units of the projected coordinate system (PCS) of the elevation raster data. For example, if data is in a Universal Transverse Mercator (UTM) PCS, the unit of distance will be in meters; if data is in State Plane PCS, the unit of distance will be in feet (US) as shown in the following figure.

feet-vs-_feet-copy-300x148.jpg

However, sometimes it might be inconvenient and hard to understand the  following: The elevation changes from 1,200 feet to 1,400 feet over a  distance of 400,000  feet.

This may be a little like weighing a person in ounces, or counting age in minutes…weight-300x143.png

In fact, it is more meaningful when data is displayed in the following manner: The elevation changes from 1,200 feet to 1,400 feet over a distance of 80 miles as illustrated in the following figure.feet-vs-_mile-copy-300x149.jpg

Often there is a need to display the horizontal distance on the X axis of a Profile Graph in a unit other than the PCS units of the data, so as to do a quick comparison between different units or for better understanding of the data.

Here are the steps to change the horizontal distance units (units of X axis) on a Profile Graph without changing the PCS of elevation data:

1)      Open Data Frame Properties  (View > Data Frame Properties)

2)     Click on Coordinate System Tab

3)     Click Modifyd1-252x300.png

4)      Select the desired units (miles, kilometer etc.)d2-218x300.png

5)      Click Apply.

6)     Click OK.

7)     Create a new Profile Graph.

And remember, don’t weigh yourself in ounces. Consider changing the units.

Additional links: Fundamental of creating profile graphsTarun J. - Raster Support Analyst

Filter Blog

By date: By tag: