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Eric Compas

11

May
2018

In News

By Eric Compas

Upgraded GIS Center servers (move to HTTPS)

On 11, May 2018 | In News | By Eric Compas

Hey, it seems like a small thing, but we’ve recently completed a substantial effort to upgrade our server environmental and migrate to HTTPS on all our operations. Everything should be up and running now. Please let us know if you find anything that’s broken 😉

06

Dec
2016

In Field mapping
GPS

By Eric Compas

New “survey grade” GPS equipment

On 06, Dec 2016 | In Field mapping, GPS | By Eric Compas

For many of our mapping projects and contracts, from mapping storm sewers to electrical networks, we’ve needed more accuracy than our “resource grade” Trimble GPS units can provide. This has been particularly true for our UAV imagery. Since we’re producing images with resolution of between 1-5 cm, we need ground control that’s as accurate or better than this resolution. Our Trimble units under ideal conditions can provide 15-30 cm horizontal accuracy — not good enough. Plus, we’re hearing more about local government units purchasing higher-accuracy devices which our students need exposure to. Read more…

Yellowstone area field trip

On 21, Nov 2016 | In Cartography, Greater Yellowstone | By Eric Compas

As part of my research sabbatical this year, I’ve recently returned from the first of two research trips to the Yellowstone region. The goal of this trip was to visit the archives at both Yellowstone and Grand Teton National Parks to collect information about ecosystem management and private lands and to acquire more information from the US Forest Service about their acquisition and exchange of private lands. I was able to collect over a 1,000 pages of archive documentation on the Greater Yellowstone Coordinating Committee, the parks’ role in ecosystem management and influencing adjacent private lands, and related correspondence. For the GIS analysis, I was successful in acquiring data from the USFS to recreate forest ownership for the last 40-50 years.

Read more…

02

Oct
2016

In Water quality

By Eric Compas

Comparing water array with conventional unit (YSI Professional Plus)

On 02, Oct 2016 | In Water quality | By Eric Compas

One of the requirements of the Testing the Waters’s grant with WI DNR was to conduct a comparison of our array with a conventional, trusted unit. We finally got access to a professional-grade unit, a YSI Professional Plus (thanks Dr. Dale Splinter!). This unit is around $3,000 for the dissolved oxygen, conductivity, temperature, and pH probes that it has with it.

Here’s a link to the full analysis: Comparison of array with YSI unit. Read more…

02

Oct
2016

In Water quality

By Eric Compas

Initial analysis of Testing the Waters data

On 02, Oct 2016 | In Water quality | By Eric Compas

For the latest Rock River Coalition newsletter, I finally got around to doing an initial analysis of the Testing the Waters data that we collected over 11 days of paddling. The full article is available here: Testing the Waters: What did we learn? Read more…

19

Sep
2016

In News
Water quality

By Eric Compas

New video about our “Testing the Waters” project

On 19, Sep 2016 | In News, Water quality | By Eric Compas

Jeffrey Pohorski, one of the video producers in Media & Marketing at UW-Whitewater, did a great job telling the story of our adventure down the Rock River this May:

Link to full YouTube video: https://www.youtube.com/watch?v=uBet7Do_KdI
Read more…

13

Sep
2016

In News
UAV/drone

By Eric Compas

Commercial remote pilots license

On 13, Sep 2016 | In News, UAV/drone | By Eric Compas

Under the new FAA Part 107 rules, Dr. Compas is taking the test to obtain a commercial “remote pilot airman certificate.” This will allow us to conduct University research flights under the Part 107 rules.

Read more…

13

Sep
2016

In News

By Eric Compas

Rebuilding website

On 13, Sep 2016 | In News | By Eric Compas

Sorry for the mess! Please be patient as we rebuild our website. It was about time to do some cleanup around here.

15

Sep
2015

In UAV/drone

By Eric Compas

Drone flights over WI state property

On 15, Sep 2015 | In UAV/drone | By Eric Compas

We’ve been discussing with Wisconsin Department of Natural Resources officials potential UAV/drone flights over  their property. Turns out there are laws that do restrict flying over some state property including using drones to hunt or fish or using drones in a way that could disturb wildlife. An addition, some areas such a state parks and state natural areas are completely off limits. Overall, these restrictions seem fairly reasonable.

UAV Guidance – Wisconsin

04

Aug
2015

In Water quality

By Eric Compas

Additional analysis of Milwaukee water quality data

On 04, Aug 2015 | In Water quality | By Eric Compas

We’ve conducted some initial analysis of our data from last Friday (more here). Our goal was to be able to better visualize our sample data along the stream corridor. As a geographer, I turn to a map as my first impulse, but in this case, it’s certainly not the only way of viewing our data. In particular, we were interested in comparing the values from each of our units and better visualizing trends on our metrics along the stream corridor.

So, from our magic GIS hat, we pulled out some dynamic segmentation tools to “linearize” the data we’ve collected. Put simply, we moved each data point to a stream center line as defined by USGS’s National Hydrography Dataset (NHD) yielding a distance along the stream. We could then plot our metrics, e.g. dissolved oxygen, versus distance along the stream in a conventional scatterplot allowing us to compare our two sample units and samples through time.

Here’s a visualization of the “linearization” of our data:

Linearization of stream sample data

Linearization of stream sample data

In ArcGIS, each data point (in red) was moved to the NHD stream center line (points in blue) if it was within 100 meters of the center line. In addition, each new blue point was given a distance along the stream stretch.

As of yet, these data are unfiltered. We haven’t removed known extraneous and/or invalid readings.

First, data from the Kinnickinnic

(which can be compared to the map here)

Note that the blip in temperature is due to Unit #2’s temperature element being removed from the water for a time. Temperature is almost the same for both units.

Kinnickinnic dissolved oxygen

Dissolved oxygen is also very similar (thankfully, after quite a struggle) between the two units. The mess to the left in the graph is explained below.

Kinnickinnic conductivity
Electrical conductivity also shows close correspondence between the two units except with fairly high values. We use a two point calibration at 84 uS and 1,413 uS, so this divergence outside the calibration range is not all that surprising.

Kinnickinnic pH - July 31

Our pH values, while still exhibiting similar trends, show the greatest discrepancy between the two units that, disconcertingly, varies throughout the sample. We’ll be revisiting our calibration procedure for the pH probe to make sure we’re consistent with each unit.

For the Menomonee River

menomonee-temp-july31

menomonee-do-july31

menomonee-ec-july31

Menomonee pH - July 31

For the Menomonee, our units again performed similarly, with all but pH matching fairly closely.

Why the jagged or seemingly noisy segments? This is due to including both the paddle out and back along each segment on the same graph. So, for dissolved oxygen on the Menomonee for example, Unit #3 (in orange) returned significantly different values on the way out as compared to the way back in the 6,200 to 6,700 meter range. Mike, paddling Unit #3, took a different path on the way back in this segment and there appears to have been a significant cross-sectional change in the DO across the stream profile. Since we’re linearizing and combining both in- and out-paddles, our line graph bounces back and forth across these values.

Obviously, we still have a lot of explaining to do for each of these trends. We’ll leave that for another post for now.