Week 8 - Isarithmic Mapping

This week's lab involved creating isarithmic maps - basically, the kind of flowing line maps that are usually seen with weather-related data. We were tasked to create two maps - each essentially the same, except one shows precipitation data using continuous tones and the other with hypsometric tints. Both maps needed to employ the hillshade effect, and one of the maps needed to show the display with contour lines. A final twist on both these maps was to employ a certain level of craftsmanship - essentially, to own our maps!

The continuous tone map.

The hypsometric map.

Technical Details

I settled on a landscape view, as I felt that would depict the data the best. An overall light gray background was used so that the really important map elements (the map itself and the legend) could further stand out with a plain white background.

The symbology presentation is what is so different about each map. To create a continuous tone map, one uses a stretched symbology, and for this map I had standardized the labels to the nearest multiple of 5 to show the beginning, center, and end of the range. After a few minutes with the legend properties (specifically, modifying the patch settings so the bar wasn't compact) I was able to get my legend to display correctly. What I couldn't do was get the values and color ramp to flip, so that the bar would read from '5' to '260'. Perhaps that's just not the done thing with these types of maps?


To create the hypsometric map I used a classified scheme. This is very similar to what I had done with the choropleth maps, except this was created using a raster file. The end result was still a color ramp being employed for the symbology. Getting the legend to display properly was a bit tricky - not only did I mess with the patch settings but I also needed to mess with how the text for the values displayed as well. This may have been a bit easier if I had a vertical legend display, but I had already set something of a style precedent with my continuous tone map... and in the end I finally got things to work without having to resort to fiddling with it in CorelDraw.

I kept the contour lines for both maps... to my mind each looked flat without it (bad pun, I know). I suppose I could have gotten away with not having contours for the hypsometric map, but after I had seen it with contours... well, why go back? Oddly enough the default color ArcMap gave me for the contours worked out, although I did some experimenting with just about every other color under the sun before realizing it. Sometimes... well, very infrequently... the default settings are good!