Bring out the GIMP!

That’s right, I like GIMP—the GNU Image Manipulation Program, that is. It’s basically Photoshop® without the cost. Actually, the fine developers working on GIMP wouldn’t really like that description, but now you know what it does. Of course, like most pieces of advanced software, there is a somewhat steep learning curve, but with a little patience and a tiny bit of skill you can get some remarkable results.

For my last post on backpacking in the Lost Creek Wilderness I included an elevation profile for the trip. I made the profile by tracking out the route in TOPO. We have a rather old version of the software covering a smallish portion of the central Colorado mountains, but it covers the region we were in. Generally speaking, it’s pretty easy to draw out the map. You just follow the route with the mouse. In this case, I had to recreate some of the trail. I guess our electronic maps are a bit out-of-date. Nevertheless, with the topo map next to me, it was pretty easy to draw in the trail segments that were missing. Once done, you can automatically draw the elevation profile for the route and calculate the actual distances. It’s pretty neat software, because it uses digital raster graphics for the maps. This means that there are actual elevations encoded into the maps for each pixel. By taking the rise and fall into account, you get the actual overland distances traveled and not the 2-D projection as you’d get if simply measuring the route with a string or route tool. This really only matters for very hilly routes, as most don’t make that much of a difference.

The original elevation profile from TOPO. Pretty hard to read, and worst of ala, backwards!
The original elevation profile from TOPO. Pretty hard to read and, worst of all, backwards!

For some reason, after drawing the entire route, the elevation profile was backwards! I couldn’t figure out why it kept drawing from the end of the route to the beginning, but nothing seemed to make a difference. I exported the profile as a jpeg, but it was hard to read with the horrible blue background. Clearly this needed to be cleaned up before I could add it to Gribblog! Well, GIMP to the rescue.

After opening the jpg in GIMP, I first flooded the blue background with white to get a better looking profile. With the black border along the top of the profile separating the background from the profile, the software was able to recognize the background area without any trouble, so only a few pixels needed to be manually updated.

Next, I removed the blurry CAMP label above the marker indicating where we spent the night (relative to the profile). With a clean looking profile, I carefully selected the actual route, leaving all of the mileage and border in place, and cut the profile from the image. I created a new layer the same size as the original image and pasted the profile into the new layer. Now with the mileage, borders, and background separated from the profile, I flipped the profile horizontally within the new layer while leaving all of the surrounding info as it was.

The elevation profile for our trip. Notice how steep the last hill is—especially the downhill side!
The GIMPed elevation profile—now much easier to read and running the right direction! especially the downhill side!

Finally, I added a new label for the camp using a much larger font size and exported the image as a portable network graphic. I ‘m sure a more talented graphic artist could do an even nicer job, but I’m pretty happy with the results. If you need to occasionally edit some images (or even if you are a talented graphic artist) check out GIMP; I think you’ll find it very useful, and I know the price is right. You can find a version for just about any operating system under the sun.

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