#10: [20-Oct-23]

#9: [09-Jun-19]

#7: [28-Feb-16]

#6: [30-Sep-11]

#3: [10-Jun-06]

#5: [19-Apr-06]

#4: [27-Mar-06]

#2: [30-Sep-05]

#1: [28-Apr-01]

09-Jun-2018 -- This is the first out of 12 reports reaching confluence points in Poland. During our 3-day trip to Poland, we devoted one day entirely for confluencing – to visit the maximal number of confluence points. We had reached 10 points in 2005, 12 points in 2015 and 13 points in 2017. Would it be possible to beat our record?

To optimize our route through Poland, I calculated all driving times between neighbouring confluence points using Google Maps. I also estimated the hiking times to the confluences including return, considering the optimal parking distance, the terrain, the existence of footpaths and the vegetation. The result was an inscrutable graph with nodes and edges between them. But how could I find the optimal route?

To find the quickest route, I wrote a simple MATLAB program based on a randomized global optimizer, also called Monte Carlo method that cannot guarantee to deliver the quickest route, but a very quick route in reasonable computation time. This way, I minimized the sum of travel times between 14 confluence points, the number of points necessary to break the former record. The output of this program was a route that was obviously a very good route and we prepared for it.

Critical was the daylight time. We had to arrive at the first CP with the first daylight and reach the last point before nightfall. At latitudes of 52° north, the summer daylight is long and the beeline travel distances between longitude lines of around 70 km are significantly shorter compared to the distances at the equator. However, the distances between latitudes remain at 110 km. Also critical were the pauses. To minimise them, we changed drivers, and the one who was not driving was eating our prepared food consisting of an aubergine dish cooked by Elionora as well as two loaves of bread, cheese, tomatoes, etc.

We arrived at Warsaw the evening before, spending a short night in the city. The next morning, our alarm-clock woke us at 3:00 AM. We left our hotel at 3:30 AM for a 25-minute drive to this confluence point until we were able to park the rental car at the planned spot right at a country road in 480 m distance from the confluence point.

We walked along the edge of a birch forest. The morning dew wetted our feet and legs. The mosquitoes were very active at that time of the day using the opportunity for such unexpected prey. At a distance of 30 m, we were stopped by a water filled ditch. We already took the pictures for the documentation at this location, until we found an easy way around the ditch. The second set of pictures was then taken at the exact zero spot: in a meadow with high grass, herbs and flowers.

Altogether it took us 17 hours 16 minutes to visit all 12 points, taking the picture of the first confluence at 4:19 AM and the last at 21:35 PM. On average it took us 1 hour 34 minutes to get from one point to another (on average 88 minutes driving and 9 minutes hiking). The driving distance was 1084 km, 33 km more compared to the Google calculation of 1051 km.

Here is an overview over all 12 confluences, including a snapshot the of confluence hunters as they appeared at the sites. Elionora is counting the points using Chinese hand signs.

CP Visit Details:

• Distance of car parking: 480 m
• Time to reach the CP from the road: 10 min
• Time at the CP: 4:19 AM
• Measured height: 102 m
• Minimal distance according to GPS: 0 m
• Position accuracy: 3 m
• Topography: flat
• Vegetation: meadow with grass, herbs and flowers. Birch forest nearby.
• Weather: clear sky, 18° C (felt temperature)
• Given Name: The Surrounded Ditch Confluence

The story continues at 52°N 20°E.