srdgraph

Prerequisites

Well, the utility is a command line tool that uses Perl – so that’s a good start for requirements. You need some recent version of Perl: I used the tool only with 5.8.0 and appreciate feedback.

The packages required to run the utility are:

• GD::Graph
• POSIX
• S710

GD::Graph

GD::Graph is the graphical core of the utility. It takes care of generating a graph given the data, and you as a user don’t have to do more than presenting it and – voila! – it’s there.

hrmcat

How Is It?

I called the project hrmcat because I started thinking it would end up being a set of parallel utilities that would complement the existing srd* utilities. Then I found that it made little sense to proceed this way and simply added the capability of reading HRM files to the srd* utilities. Indeed, the change was so minimal that aside from a new C file (for the parsing of the HRM file itself), the modifications to Dave’s code consisted only of a minor change to the file reader. If it fails to parse a file as SRD file, it falls back to HRM. And since the formats are completely incompatible, you risk not one file being mistaken for the other format.

HRM File Format

Overview

The Polar S7xx heart rate monitor comes with Windows software to download and display workout data. That’s nice, but for those of us that don’t use Windows, it’s really not going to work.

Dave Bailey, a physicist turned to the dark side of programming like me, has written software to download and display workout data on Linux. Unfortunately, the format he uses to store data is not the same as the format used by the Windows software.

Polar HRM

What’s this?

The Polar S7xx family of bike computers has a handy feature that allows you to download your exercise data to a PC running Windows. Thanks to the work of Dave Bailey, the Polar family now runs on Linux, too. Dave provided software to read Polar data into the PC and to display it in graphs. Later, he added a Perl interface to the library that makes his work accessible from scripts.

Half Dome Trail, Yosemite, CA

{moszoomimglink:Nothing stops you for}Yosemite in the early summer is a wonderland of incredible beauty. The wildflowers are still in bloom, the waterfalls are strong and powerful, and the temperatures are high enough to allow for a quick dip in the water. What better time to explore a great day hike than this?

Driving Up

My friends deserted me when it came to going up the mountain. It didn’t sound like fun in their eyes: to drive up in the early morning, get to Yosemite and start a long day hike to the top of a mountain, then drive back in the night, fearing the weekend rush hour traffic?

Four Mile Trail, Yosemite, CA

{moszoomimglink:First view of Yosemite – El Capitan and Half Dome}Have you ever gone to Yosemite? Well, I had been living in California for years before I took the time and drove there. It was a chilly autumn morning, the leaves were already brightly turning and I had nothing better to do.

I left early and stayed no time. To a certain degree, I only wanted to say I had been there. Tell myself, that is, since there was nobody else who would have cared.

Kilauea Iki Crater, Big Island, HI

The Big Island of Hawai’i is famous for its volcanoes. It actually is not one, but five volcanoes that are joined by overlapping lava flows. They vary in age and activity, and the youngest and most active of them has been the center of attention ever since mankind reached the islands.

{moszoomimglink:It was really flowing} Kilauea means spewing, and no volcano on Earth could be as true to this name. Kilauea has been spewing incessantly since 1992, and to this day you can hike up the brank new lava and see the red flow coming down the mountain.

Haleakala Crater, Maui, HI

{moszoomimglink:12-49 Focus on the cloud and the sky turns blue} Maui is made up of two volcanoes joined at the hip by a low-lying valley. The Western volcano, aptly named ‘West Maui Mountains’ is old and weathered, while the Eastern one, Haleakala, erupted as recently as 1790.

Haleakala is a gigantic presence in the backyard of Maui. Its gentle slopes carry nature from the tropical paradise of the Hana coast to a harsh, almost Alpine summit. In between, you’ll find cowboys tending herds and flower farms, wild rivers and incongruous deserts.

Awaawapuhi Trail, Kauai, HI

Reading up on Kauai you get easily turned on by descriptions of its marvelous natural beauty. They call it ‘the Garden Isle’, and it is so special that even Hawaiians will trek out there to visit. Kauai is the backdrop for innumerable movies as well as the scenery behind a great many honeymoon pictures.

{moszoomimglink:21 Kalalau Valley from high above} There are plenty wonderful hikes in Kauai, from short paths to a lighthouse to multi-day excursions to Kalalau Valley, a miracle of inaccessible beauty. A great many wonderful hikes are concentrated around Koke’e state park, on the West side of the island, up on the mountain that forms the core of Kauai.

The Big Island

{moszoomimglink:Waipi’o – tiny Hi’ilawe falls} I am writing this fresh from a one week vacation to Kona, spent mostly exploring and marveling at the miracles of this biggest of the Hawaiian islands. It is so big, indeed, that it would easily fit all other islands combined.

{moszoomimglink:All of Mauna Loa} Like all other islands in the chain, Hawai’i is formed by volcanoes that rise up all the way from the bottom of the sea. While underwater, the lava cools very quickly, generating a mountain that is very steep. Once the ocean surface is passed, the lava turns out to be very fluid, so that the aerial part of the islands is quite flat. Don’t expect the volcanoes to look like Mount St. Helens or Vesuvius: they are gentle in slope, and the only really steep grade is where erosion has eaten away a chunk of mountain.