After finishing writing about my cross-continental bicycle ride in September of 2014, I began exploring how to provide an approximate mapping of the journey and an elevation profile. Collecting and processing the data was straight forward and easily done, providing visualizations not so much. Rather than using a mapping service such as umap or Google Maps, I desired to provide the maps and elevation profiles as Scalable Vector Graphics (SVG) files. Therein lies the opening of the rabbit hole.
Initially, I had planned on using umap to provide maps of my track across the continent. umap, however, does not provide any means of creating elevation profiles, leaving me to generate that data set on my own. In the process of exploring the raw elevation data, I realized that the profile would be quite jagged and ugly, so I researched data smoothing algorithms. Once, I found an algorithm; I needed a means of viewing the results.
Initially, I was spitting the data into comma separated values (csv) files which necessitated a round trip to an external spreadsheet and graphing program since I don’t have Microsoft™ Excel installed that meant uploading and processing the files through Google Drive. This process was slow and exceedingly suboptimal. I looked for a better way. Enter xgraph.
Xgraph is a fairly simple program that does most of what I want, accept data and return them graphed. It does not however save the graph to svg. Since xgraph is open source, I began looking into rewriting it somewhat to produce my desired output. Long story short, this led to a series of diversions from my goal, create elevation profile in svg.
I could right now after all the diversions begin attaching elevation profiles to the appropriate posts, but they are still somewhat ugly, and I am working on creating the svg maps for my ride.
While I am nearly ready to generate all the appropriate files and data, I am still working out exactly what and how to display. I would also like to use the maps as an interface to the weblogue posts. Soon.
© 2015 David P Henderson. Some rights reserved.