Somewhat accidentally, I started adding hillshade and then rivers and waterbodies to the choropleth maps I was making up. I was shocked by the simple beauty, and how one could make a map much more attractive by adding these relatively minor and unimportant details to a map.
![Untitled [Expires August 15 2024]](https://andyarthur.org//data/photo_015456_large.jpg)
A little hillshade on a chorpleth map can sure make things a little prettier.
The hot thing in the GIS world today is the LIDAR elevation mapping, which uses airplanes to map elevation with an accuracy down to 1 or 2m (3-6 ft). Most maps traditionally use Digital Elevation Model mapping, which is about 10m accurate, which gets you elevation numbers which can be off as much as 30 feet, and is based not on actual computer imagining, but instead on old topographic surveys which don’t always reflect the latest data.
I had previously tried to down the Albany County contours from the NYSGIS website, which are available in the ERSI GDB format, how apparently the contours were made in an older version of GDB, which lacks an open source driver. However I also discovered yesterday that NYSGIS offers all that data as conventional DEM files, which are easily read by almost every GIS client.
There are a lot of interesting possibilities for using these higher resolution files.
Recently captured elevation data is available in digital elevation model files for many parts of New York State if you know where to look on the NYS GIS website.
Handy bash script I wrote, or actually adapted, for switching between your HDMI monitor and your laptop screen — you just run this when you log-in (also opens or closes gkrellm, which doesn’t fit on the tiny laptop screen) …
#!/bin/bash
# roughly based on:
# http://unix.stackexchange.com/questions/4489/a-tool-for-automatically-applying-randr-configuration-when-external-display-is-p
# laptop screen is LVDS1
# 1080p large-screen is HDMI1
# default monitor is LVDS1
MONITOR=LVDS1
# functions to switch from LVDS1 to HDMI and vice versa,
# give 5 seconds to detect modelines for HDMI monitor or fails
# as it takes a little while for modelines to be auto detected
function ActivateHDMI {
echo "Switching to 1080p monitor, HDMI1 in 5 seconds ..."
sleep 5;
xrandr --output HDMI1 --auto --output HDMI1 --primary --output LVDS1 --off
gkrellm -g -0+25 &
MONITOR=HDMI1
}
function DeactivateHDMI {
echo "Switching to laptop screen, LVDS1 now ..."
killall gkrellm
xrandr --output LVDS1 --auto --output LVDS1 --primary --output HDMI1 --off
MONITOR=LVDS1
}
# functions to check if HDMI is connected and in use
function HDMIActive {
[ $MONITOR = "HDMI1" ]
}
function HDMIConnected {
! xrandr | grep "^HDMI1" | grep disconnected
}
# every one 1 second
# poll to see if HDMI1 is connected
while true
do
if ! HDMIActive && HDMIConnected
then
ActivateHDMI
fi
if HDMIActive && ! HDMIConnected
then
DeactivateHDMI
fi
sleep 1s
done