Rainflow Direction near Riga using GRASS 6.4.1

  This map was created using the GRASS 6.4.1 Hydrology program and used the elevation file to calculate rain water flow and direction.  The short black colored lines both straight and curved shows the direction and strength of rainwater flow.  The map also shows railroads in red and roads in black.  City streets in light blue.  Luckily for Riga, there are not many strong rainwater flow marks in its' region.

Detail of Central Riga with Visibility Data from the Freedom Monument

In the experimental map below, I converted the elevation map of Latvia which is a raster map into a vector map with contour lines for each five meters of elevation.  I magnifiied the central area as well.  The yellow areas are those areas that are visible from the top of the Freedom Monument according to the GRASS 6.4.l analysis done before.  A closer look will reveal that those yellow areas seem to be of higher elevations and they are "nested" showing that those areas are hills.  Since many of areas have contour lines that are far apart, except for near the river, we could say that the terrain of Riga is relatively flat?  In the map, railroad lines are shown in red, major roads in black and contour lines in green.  The distance between contour line is 5 meters of elevation.

Riga Visibility Data Georeferenced Unto ARCGIS Riga Detail Map

In the map below, I took the visibility data from the Freedom Monument observation and georeferenced it to a more detailed ARCGIS map of the Riga region.  The results indicate that the visibility detail is not so concentrated when georeferenced into a more detailed observation map.  The yellow squares indicates that for the detail that is available, the visibility deta generated in GRASS 6.4.1 shows that the Riga region is relatively flat and that not considering buildings, visibility taking height into consideration from the top of the Freedom Monument is very great.  The X's are villages, some of which was used for georeferencing.  This is only an experiement, folks.

Calculating Visibilty atop Riga's Freedom Monument using GRASS 6.4.1.

  What would I see if I placed a camera atop of Riga's Freedom Monument?  Using GRASS 6.4.1. I used as an input the coordinates of 56.57 and 24.647 and I listed the height of the viewer at 42 meters, the height of the monument.  I used the default range of 100000 meters and the results are shown above.  It seems to me that most of the country would be visible?  Notice that the thin lines, which are either railroads or roads that I added as shapefiles to the map, have no images around them.  Perhaps these roads and railways are at lower elevations?  At any rate, I cannot understand the results and perhaps I did something wrong, but it was interesting to do this experiment.  Notice that for one of the pictures, I choose one with trolleybus and tram wires!  The results indicate as follows:  If I was standing atop of the Freedom Monument and if no buildings blocked my view and I was able to see the flat surface of the earth, I would see most of the yellow areas extensively into the interior and I would see higher elevations (in red) in the distance (over 150 meters high).  I would also see the island area across the water.  Of course, the buildings in Riga would block my view because this calculation was based on natural elevations only and did not take into effect the height of surrounding buildings.  The white areas would be hidden because they are low or because they are behind a high elevation area.

Calculating Visibility from Riga, Latvia

In the map above, I used GRASS 6.4.1 to calculate visibility from the ocean near Riga.  I used coordiates 24.10, 57.07 in the projection and I set the range to 5 X 10 (6) Meters.  The result is based on the elevation file and shows a thin line of red dots along the shoreline and on a neighboring island.  This theoretically means that an observer standing at the point that the road runs perpendicular to the Ocean will find visibility to the shoreline and the ocean, but not much on shore.  This is only an experiment and I am not sure of the results; there may be an error here.

In my choice of x,y coordinate, I picked one at random and I am not sure if it is in the City of Riga and the height of the elevation of the observer is 1.5 meters or the height of a person  A more interesting perspective would be a calculation from a point of interest, such as the top of the railroad bridge near 13 Janvara iela or other point.  If someone has a nice point of interest to calculate visibility from Riga, I will nead the x, y coordinate and the height in meters.

Example:  Freedom Monument, 42 Meters High, 56" 57,  24"4.

Regards,
Tramway Null(0)

Riga Latvia Tram Route Map

  I found this map at the rapid transit map directory that I posted earlier regarding the University of Texas.  I posted this map because it is a good companion to the two Riga tram youtube videos that I posted. In the video showing the first part of the tram route number 5, which starts at llguciems on the east bank of the river, I was surprised what appears to be a rural area is so close to the city center.   This is the video of a "trolley disconnect" which is very interesting.  Does the disconnect take place just before Darza Iela?  On Riga tramways, the stops are announced by automated recording and this map can be very helpful in tracing the route on the videos that I posted and others that are on the web.  Notice how long the Ilguciems-Milgravis route is.  Enjoy!
http://www.lib.utexas.edu/maps/new_york.html  Check out the University of Texas links to rapid transit maps on the web.  You will need to scroll a bit, the link above is not direct to the rapid transit map site.
Tramway Null(0)

Why are Riga Tramway Trolley Poles so Long?

  In another blog, an observer posted the above question.  Viewing the wonderful "Riga Latvia Tramway Route 4 Video" posted earlier, I was able to see many scenes with the overhead.  I am not an overhead expert, but here are some of my oberservations:

1.  When a two way streetcar crossed a trolleybus line, the overhead hardware appears to be that of one trolleybus lane crossing another trolleybus lane at right angles.  Or in other words, the two tramway wires, one let us say going south and one going north join to what looks like a 180 degree trolleybus crossing.  This means for one of the tram wires will be significantly out of place and needs a long pole.  See  "Observed in Riga Diagram".  Riga  has a number of trolleybus lines.  In order to avoid complex tram-trolleybus overhead hardwire at crossings, see top right diagram, a simple trolleybus crossing is used where one of the tram wires is significantly shifted. In a two way tram and trolleybus crossing, instead of having four pieces of complicated overhead you only need two.
2. I believe that trams that have pantographs need more complicated overhead where there is a trolleybus crossing.  This is avoided using trolley pole technology. Where there is trackwork, I see that the overhead in Riga is shifted significantly.

These are my guesses only, I do not work in this field.

Tramway Null(0)
The picture to the right is a traditional trolleybus crossing.  In Riga, this appears to be adopted for a tram - trolleybus crossing using one piece of equipment.

More Riga Trolleys

   In this short video, you will see some shots that concentrate on the area around the Centraltirgus area of Rigas.  You will see more streetcar equipment types and a commuter train that goes over the railroad bridge that you saw in the first video posted on Riga.  You will get to see that mysterious underpass that looks like a subway station entrance.  Riga hoped to build a Metro system but was not successful.  Perhaps the underpass was a demonstation of what a future Riga subway station would look like.  The city looks different in the rain and you will get to see at least the Centraltirgus (Central Market) area from a different angle.