Source: Linder, B. " Bleecker Street Line: The Last Horse Car Line in New York City" In New York Division Bulletin, Electric Railroaders' Association, Vol. 32, No. 2, February, 1989, p.6.
The map below as presented by B. Linder, is as of 1907. The line started as a horse car line in 1864 and was never converted to electricity or battery. The line opened for traffic as of 1866 and there is not a complete record of the route changes. In 1898, the line reached the 23rd Street ferry and around 1903, was from 14th Street and 9th Avenue to Broadway via Bleecker and return via West 4th Street. The line was discontinued on July 26, 1917. Many of the smaller lines in Manhattan did not have enough traffic to warrant it to be converted to electric conduit. Some lines ran on battery power only and some experiments were conducted with compressed air. With the opening of new subway lines around this time, the line was abandoned even though it was a crosstown line. Shall we say that this was the beginning of the end?
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Webrings - Maps - Trolleys and More
Monday, April 28, 2014
Thursday, April 24, 2014
New York Times Writer Suggests Harborfront Streetcar Line in Brooklyn to Long Island City Queens
In his article, Kimmelman says streetcars make sense for that part of New York because the sections of Brooklyn and Queens near the line he ...
I am having trouble linking the original article. More to follow
The line suggested, would go from Red Hook (Ikea) to Long Island City in Queens. He suggests a new bridge for the streetcar should be built crossing Newton Creek. Kimmelman suggests this would stimulate development. I say that this is fine, but any modern streetcar is more comfortable and smooth riding than any bus. More to follow... Copied Material from NYT article April 24, 2014 below?: I may not have the correct source, please excuse me I am having trouble with my computer (tramway null(0). I am not sure of the source of the material below:
There’s a wonderful term for the dirt trails that people leave behind in parks: desire lines. Cities also have desire lines, marked by economic development and evolving patterns of travel. In New York, Manhattan was once the destination for nearly all such paths, expressed by subway tracks that linked Midtown with what Manhattanites liked to call the outer boroughs. But there is a new desire line, which avoids Manhattan altogether. It hugs the waterfronts of Brooklyn and Queens, stretching from Sunset Park past the piers of Red Hook, to the Brooklyn Navy Yard, through Greenpoint and across Newtown Creek, which separates the two boroughs, running all the way up to the Triborough Bridge in Astoria. The desire line is now poorly served by public transit, even as millennials are colonizing Astoria, working in Red Hook, then going out in Williamsburg and Bushwick — or working at the Navy Yard, visiting friends in Long Island City and sleeping in Bedford-Stuyvesant. They have helped drive housing developments approved or built along the Brooklyn waterfront, like the one by Two Trees at the former Domino Sugar Refinery. But this corridor isn’t only for millennials. It’s also home to thousands of less affluent New Yorkers struggling to get to jobs and join the work force. Photo On the Brooklyn waterfront, south of the Brooklyn Bridge. Activity on the Brooklyn and Queens waterfronts has revived talk of a route connecting them. Credit Gabe Johnson/The New York Times So here’s an idea: bring back the streetcar. Some of this route is served — barely — by subway lines like the G, the city’s sorriest little railroad. In Astoria, stations for the N and Q are nearly a full mile or more from the East River, meaning a vast swath of that neighborhood is virtually disconnected from the subway system. It’s an area ripe for growth — for new housing, start-ups and other small businesses and industries — all the more so with the coming of the Cornell Tech campus on Roosevelt Island, just across the river and linked to Queens via the F. One can imagine another Silicon Alley spanning Cornell, Astoria, Williamsburg and Sunset Park. Right now, it’s easier by subway to get from Long Island City to Midtown, or from Downtown Brooklyn to Wall Street, than it is to get from housing projects in Fort Greene or Long Island City to jobs in Williamsburg, or from much of Red Hook to — well, almost anywhere
My Opinion:
1) Since New York City has been hostile to streetcars since the 1920's with Walker's administration ( it has been close to 100 years ) any new streetcar project should start small, in a situation where there is no or little opposition. The line described is very long and involves building a bridge. Could you image the opposition from motorist that will have to give up parking and road space, person's whose view will be blocked by wires, people who do not want to crash into trolley support poles and so on? The longer the line, more complaints from more people and also the cost.
2) Pick a area which is underserved by rapid transit, such as eastern Brooklyn or Queens, eastern Bronx and big parts of Staten Island. Build a line at the end of heavily used subway line with no other rapid transit in the area. Try to make the line partially private right of way. The passengers will see the difference between the comforts of a modern streetcar and a smelly shaky motor bus.
3) While it is nice to serve the waterfront community with the hope for development, as other critics said, is this the most underserved community? While it is true that the waterfront community may be far away from rapid transit, big parts of eastern Queens and Brooklyn is underserved as well.
4) Keep the cost down by using modern track construction that is not deep and use if possible, modern but second hand cars as a first test. Plan your first line were the public wants such a line. Very fancy neighborhoods may object to having their views blocked by wires. New Yorkers do not know that world capitals of Europe, such a Riga, Moscow, Sankt Petersburg, and Warsaw in the past had their palaces and art museums surrounded by "wires", both trolleybus and tramway.
5) Instead of stressing development, which is great, stress the comforts of traveling by tram, which is quiet, odorless and smooth and cost effective and environmentally friendly. Choose a candidate bus line that meets the criteria for such a conversion. There are hundreds of bus lines in New York City to choose from.
6) If the above line which is very long is built, I would, if we had the money, make a branch go over the Williamsburgh Bridge to the Essex - Delancey Street abandoned trolley terminal. In this way, waterfront communities would have a one seat ride to the Lower East Side and or have excess to various subway lines such as the F, J, M and Z lines. What a waste if such a valuable transit facility, such as the old trolley terminal at that location with tracks and wires should become a underground park? But, could you imagine the difficulty of bringing streetcars on a New York bridge because of opposition from the motoring public and the New York City Department of Transportation? I am not sure of this nor do I have the source, but for a period of time, the BRT or BMT wanted to build an extension for streetcar service north of the trolley terminal at Essex Street. If this happened and a streetcar subway system developed, chances would have increased for streetcar service would not be abandoned since of the good service that such a service would have provided. Note the tram subways in Philadelphia and Boston that survived the move to motorize everything. Note the many tram subways in Europe.
More to follow: Tramway Null(0)
Wednesday, April 16, 2014
The Abandoned Myrtle Avenue Station
This photo was taken off the web. This station, at Myrtle Avenue and Flatbush Avenues in Brooklyn is not in service. Originally two local platforms, only the northbound half is partially intact and Manhattan Bridge trains pass it every day.
More to follow this in the future. Behind the wall are two "express tracks". I believe the station was abandoned in 1956 due to the total reconstruction of the area to increase through service . The southbound platform does not exist today and was ripped up to make room for a fifth track in the area. This was to increase service through the DeKalb Avenue Station once the Christie Street Loop line opened in 1967. Upstairs, the Myrtle Avenue El was still existing until that time. Myrtle Avenue in Brooklyn was associated with the three forms of electric transit, namely els, streetcars and serveral underground stations along the way. In recent years, there has been much residential building in the area and I wonder if opening of the northbound platform to passengers would be helpful. I believe that the length of the station has not been expanded and that the area of the platform has been taken over by store rooms. The station, if opened, would require a major investment of money. I have no statistics to show if an reopened station would be helpful or how far the station is away from DeKalb Avenue, the station to it's south.
Possibly more to follow.
Here is a 1951 aerial view of the Myrtle Avenue - Flatbush Avenue Ext. Intersection. I remember, as a child, seeing a green arch near the Myrtle Avenue El at this area ( above the station). You can make out the arch from the aerial shot below. Surprisingly, a 1920's aerial does not show the arch. Perhaps the arch came after Flatbush Avenue was extended for the Manhattan Bridge.
Flatbush Ave Ext.
Myrtle Avenue is at the center gong from left to right. You can make out the arch at the Flatbush Avenue - Myrtle Avenue intersection. The station is underneath with tracks leading to the Manhattan Bridge.
Tuesday, April 1, 2014
Some Interesting Views of the 59th Street Queensboro Elevated Line
Recently, Dave of Subchat posted a series of clear and rare photos of rapid transit topics of high quality. I would like to share with you two of them; views of the elevated line that crosses the bridge to Queens.
In this 1940 picture, we seem to facing north along 2nd Avenue and we see the turnoff to the Queensboro Bridge. The Bishop Crook streetlamp has a sign that says East 59th Street. If you look carefully in the street, you can see conduit trolley track. Notice the wooden elevated cars as well. This curve also shows up on a 1924 aerial. Yes, we are facing north on Second Avenue.
In this view as well, I believe we are in Manhattan and we are facing Queens. Notice our "Friends", the two adjustable Gas Tanks. I am not sure if they are in Manhattan along the shore or in Queens.
Comparing the location of the gas tanks to the entire Queensboro Bridge, I think the tanks our nearby in Manhattan. When I have more time, I will look at an aerial of the area. Note, a 1924 aerial shows three tanks near the intersection of East 62nd Street and York Avenue. So the tanks are in Manhattan right near the river. They are sitting on some prime real estate.
Notice the conduit trolley track in the street. The elevated train seems to consist of wooden gate cars.
What a great shot. From 1940.
Below, another view of the gas tanks:
In this 1940 picture, we seem to facing north along 2nd Avenue and we see the turnoff to the Queensboro Bridge. The Bishop Crook streetlamp has a sign that says East 59th Street. If you look carefully in the street, you can see conduit trolley track. Notice the wooden elevated cars as well. This curve also shows up on a 1924 aerial. Yes, we are facing north on Second Avenue.
In this view as well, I believe we are in Manhattan and we are facing Queens. Notice our "Friends", the two adjustable Gas Tanks. I am not sure if they are in Manhattan along the shore or in Queens.
Comparing the location of the gas tanks to the entire Queensboro Bridge, I think the tanks our nearby in Manhattan. When I have more time, I will look at an aerial of the area. Note, a 1924 aerial shows three tanks near the intersection of East 62nd Street and York Avenue. So the tanks are in Manhattan right near the river. They are sitting on some prime real estate.
Notice the conduit trolley track in the street. The elevated train seems to consist of wooden gate cars.
What a great shot. From 1940.
Below, another view of the gas tanks:
Tuesday, March 25, 2014
Thinking the Impossible: Bringing Back the Culver Line
Those of us the grew up in rich rapid transit environments that had "days of glory" in the past have sometimes fantasies or thought experiments "What Would Happen If?" if some service of a much beloved line would be partially brought back. In subchat, there are individuals that mirror this thought process of asking hard questions of what would it take to somewhat restore some type of service. In the universe that we live in, it is hard to bring back what has happened in the past especially if no one shares your views or the proposal is expensive. It is especially hard like a place like New York City where after 1950, very limited rapid transit expansion took place. Take the case of Brooklyn: The last station to open was probably Euclid Avenue or Grant Avenue at the Queens border and this was probably in 1948 or 1950. In the past 63 years, so many lines and stations were destroyed, including our beloved Culver Line in Brooklyn. A vast trolley car system vanished with almost no trace.
In the map below produced in ARCGIS, various railroad and rapid transit shape files were added and building footprints. Look please at 37 th Street on the left of the picture. In discussing the culver line, it is important to remember that along 37th Street, the elevated structure was over the SBRR right of way and not over 37th Street. Private houses have been built along this right of way in may places. The black and white map shows a dotted line where the approximate location of the el structure was found.
In the future, I will discuss the Culver Shuttle Right of Way and some interesting points on the topic. We will discuss the new buildings built directly on the former Right of Way.
This picture come from an interesting web site called www.arrts-arrchives.com/NYBB.html.
This picture may be from the period of 1967 ( after the abandoned two tracks on the structure were removed and the end in 1975. The structure would remain for about another nine years. Notice the South Brooklyn RR tracks and the "coal silo" to the left of the picture. This view is facing west on 37th Street west of 13th Avenue. Actually 37th Street is to the right.
More to follow.
This picture from 1914 shows how the area looked when the Culver Line service was on the ground and before the el structure was constructed. You are facing west towards 13th Avenue and you can see the track crossing of the Church Avenue Trolley Line. You can also see a UFO just at the crossing. An interesting turnoff to the right where the gentleman is standing may be a lead to the Nassau Electric Yard which was across the street. 37th Street itself is to the right of the picture. It is this PRW in which housing is being built or it used as parking lots. Any restoration of Culver Line service, either subway or light rail would need to be now on or over 37th Street.
More to follow
. This Google Map shot is taken on 37th Street facing west towards 13th Avenue. The white building behind the trees and the brown three story tan brick building on the left of the shot were probably the same buildings shown above in 1914. Notice how narrow 37th Street is. When the El structure existed, the sidewalk on the right was very narrow. The parking lot was the location of the Culver El and underneath, the South Brooklyn Railroad. The low tan brick building on the right was the former site of the Nassau Electric Yard for streetcars. How do I know? Around 1971 a series of low wood garages occupied the site. When the building on the right was constructed, the old rubble had to be removed and it included a lot of railroad rails.
In the map below, I tried to show the path of any rapid transit facility from Ninth Avenue to Ditmas Avenue. It is mainly on or over 37th Street and not in the previous PRW. To be discussed later.
In the charts below, I write out some scenarios of what the restoration of service on the "Culver Shuttle" would be like after deciding mode, route and other options. There is almost an infinite number of options available but just remember, this is a thought experiment. An interesting thought though: " Why must service be restored to Ditmas Avenue... would Church Avenue be better because it is a potential express stop and G stops there but not at Ditmas... "
What are your thoughts?
Now that there is housing on the prior private of way, any form of rapid transit will need to take that into consideration. What is interesting about the former Culver Shuttle, is that some sections still exist or can be made operational. The Ninth Avenue Station {lower level} has three tracks with third rails available. Some of these tracks extend southeast of the station to connect with yard track and to a portion of the South Brooklyn Rail Road. Track on the surface extends to the 37th Street and Ft. Hamilton Parkway intersection. At the east end, yes, there is a small stump that leads to the Ditmas Avenue Station. This structure is probably sound but currently has no tracks on it. The tracks were removed many years after service was abandoned. This fourth track structure extends beyond the south end of the Ditmas Avenue Station. If we had the money and permission of residents and elected officials, choices must be made about the mode, destinations and type of terminals decided upon. The table below shows the many choices. If an elevated is decided, questions regarding number of tracks, station location and type of elevated. Would it be a iron "dual contracts" type of elevated or would it be a concrete affair like the line that goes to Kennedy Airport? Would the residents like an elevated structure over the street? How about a subway? As soon as the line leaves Ninth Avenue and momentary enters the open air, an incline can take the line into a subway along 37th Street. Perhaps a one track subway with one station at 13th Avenue with a passing track. What about Ditmas Avenue? Should the subway enter a ramp to Ditmas Avenue? There does not appear to be too much room for this. Perhaps a one track subway station under the Ditmas Avenue Station with an elevator to the upper level. More dreams to follow in the future.
In the map below produced in ARCGIS, various railroad and rapid transit shape files were added and building footprints. Look please at 37 th Street on the left of the picture. In discussing the culver line, it is important to remember that along 37th Street, the elevated structure was over the SBRR right of way and not over 37th Street. Private houses have been built along this right of way in may places. The black and white map shows a dotted line where the approximate location of the el structure was found.
In the future, I will discuss the Culver Shuttle Right of Way and some interesting points on the topic. We will discuss the new buildings built directly on the former Right of Way.
This picture come from an interesting web site called www.arrts-arrchives.com/NYBB.html.
This picture may be from the period of 1967 ( after the abandoned two tracks on the structure were removed and the end in 1975. The structure would remain for about another nine years. Notice the South Brooklyn RR tracks and the "coal silo" to the left of the picture. This view is facing west on 37th Street west of 13th Avenue. Actually 37th Street is to the right.
More to follow.
This picture from 1914 shows how the area looked when the Culver Line service was on the ground and before the el structure was constructed. You are facing west towards 13th Avenue and you can see the track crossing of the Church Avenue Trolley Line. You can also see a UFO just at the crossing. An interesting turnoff to the right where the gentleman is standing may be a lead to the Nassau Electric Yard which was across the street. 37th Street itself is to the right of the picture. It is this PRW in which housing is being built or it used as parking lots. Any restoration of Culver Line service, either subway or light rail would need to be now on or over 37th Street.
More to follow
. This Google Map shot is taken on 37th Street facing west towards 13th Avenue. The white building behind the trees and the brown three story tan brick building on the left of the shot were probably the same buildings shown above in 1914. Notice how narrow 37th Street is. When the El structure existed, the sidewalk on the right was very narrow. The parking lot was the location of the Culver El and underneath, the South Brooklyn Railroad. The low tan brick building on the right was the former site of the Nassau Electric Yard for streetcars. How do I know? Around 1971 a series of low wood garages occupied the site. When the building on the right was constructed, the old rubble had to be removed and it included a lot of railroad rails.
In the map below, I tried to show the path of any rapid transit facility from Ninth Avenue to Ditmas Avenue. It is mainly on or over 37th Street and not in the previous PRW. To be discussed later.
In the charts below, I write out some scenarios of what the restoration of service on the "Culver Shuttle" would be like after deciding mode, route and other options. There is almost an infinite number of options available but just remember, this is a thought experiment. An interesting thought though: " Why must service be restored to Ditmas Avenue... would Church Avenue be better because it is a potential express stop and G stops there but not at Ditmas... "
What are your thoughts?
Now that there is housing on the prior private of way, any form of rapid transit will need to take that into consideration. What is interesting about the former Culver Shuttle, is that some sections still exist or can be made operational. The Ninth Avenue Station {lower level} has three tracks with third rails available. Some of these tracks extend southeast of the station to connect with yard track and to a portion of the South Brooklyn Rail Road. Track on the surface extends to the 37th Street and Ft. Hamilton Parkway intersection. At the east end, yes, there is a small stump that leads to the Ditmas Avenue Station. This structure is probably sound but currently has no tracks on it. The tracks were removed many years after service was abandoned. This fourth track structure extends beyond the south end of the Ditmas Avenue Station. If we had the money and permission of residents and elected officials, choices must be made about the mode, destinations and type of terminals decided upon. The table below shows the many choices. If an elevated is decided, questions regarding number of tracks, station location and type of elevated. Would it be a iron "dual contracts" type of elevated or would it be a concrete affair like the line that goes to Kennedy Airport? Would the residents like an elevated structure over the street? How about a subway? As soon as the line leaves Ninth Avenue and momentary enters the open air, an incline can take the line into a subway along 37th Street. Perhaps a one track subway with one station at 13th Avenue with a passing track. What about Ditmas Avenue? Should the subway enter a ramp to Ditmas Avenue? There does not appear to be too much room for this. Perhaps a one track subway station under the Ditmas Avenue Station with an elevator to the upper level. More dreams to follow in the future.
Saturday, March 15, 2014
Using GRASS 6.4.1 To Calculate Water Flow on Mars
Hi Folks:
Most of this blog deals with mapping and rapid transit issues, particularly street railways and trolleybuses. I would like to step away for a moment from the rapid transit part and dealing with another mapping issue, mapping other worlds. Mars has always been interesting to me on account of the supposed canals. Perhaps Martians also had some form of rapid transit along the canals? At any rate, thanks to the internet and interesting map programs as GRASS 6.4.1 which does all sorts of hydrology and other operations, let us see what Mars has to offer?
The following source shots were probably unzipped from a NASA website by myself:
The map below was produced from a shape file of the Mar's surface. I produced a map in ARCGIS and then transferred the program to GRASS. The two points of observation are pointed out. One is in the center of a crater where one of the Rover modules landed in 2004. Its' approximate location is -260521.36, -87339.29. I did not get the exact location*. Notice the "river like" crack south of the crater that goes to the east. I also picked as a reference point -251316.35 and -1044693.55 which is sort of a projection of some kind near the south side of the crater..
As a experiment: What would a person at this two locations see on Mars? Here we are asking about visibility. Second, how would water flow in the "river" to the south of the crater? To answer this, we will use GRASS 6.4.1.
* The location of the rover landing is handled by a separate shape file and I will need to investigate this further. The coordinate system by default in ARCGIS and GRASS is not the same. I picked the rover location at he near center of the crater randomly since the surface appears to be relatively flat. The picture below comes from NASA. It shows sunset over the Gusev Crater which is the crater that is shown below that has a "river " extending from it's southern section. The river is called "Ma-adim Vallis".
In the map above, I used the GRASS contour generator. My range is from about +4000 m to -4000 m in 1000 m sections. Notice the river is stands out clearly from the surroundings. The colors are coded according to elevation. Essentially, this map is a elevation file that is coded according to altitude. This was done automatically by GRASS. Do you see the red circle disk with two projections on the east side near the "river" Ma-adim Vallis.. This high area will also be a frame of reference. What would an observer see at both locations if the observer is 1.5 meters high? This is the raster - terrain analysis - visibility sequence.
This is the "visibility" result from the small red disk like projection. The range is 200,000 meters.
I cannot explain why I got this triangular shape. When I do the analysis at above 200,000 meters, the system crashes completely. Perhaps this odd shape is due to a computer problem and not a visual result. The dot at the north point of the triangle is the frame of reference.
In the map above, the yellow-green triangle is the visibility from the center of the projection that has the yellow dot in the red disk. I do not know why I get such a pattern.
In the map below, the GRASS 6.4.1 hydrology program was used to indict flow areas downhill from a rainstorm. The program will ask you to supply two parameters or more dealing with the length of the vector produced and the number of "cells" that it covers. Here you will need to try your luck in case you are like me and do not know what you are doing.
The green lines are theoretical water flow if Mars had a rain storm. This was based on the elevation file provided. You can see the outline of the "river" and the outline of the crater. Notice that the walls of the river have the water flow but not the bottom of the "river" itself.
The above map was produced in GRASS 6.4.1 using the raster-hydration program dealing with water flow and is the same as the picture above except for different settings. You can see the shape of the Gusev crater and the area where the river is. The water flow is perpendicular to the river and not along it. The walls of the crater produce water flow also perpendicular to the walls.
And I almost forgot, here is the visibility at a random location near where the rover landed in 2004.
The red dot in the frame of reference in the Gusev Crater. Visibility extends only inside the crater, of course.
Notice at the right side of at the bottom of the crater there appears to be a projection of a low area which appears to be the beginning of the "river".
Another view of the Gusev Crater and Ma-adim Vallis River.
This map was produced in GRASS using the slope aspect. Various derivatives can be derived from the slope of the elevations. I believe this is a dxdy partial derivative.
Below is a map that used GRASS to produce contour lines at 500 m intervals from -4000 to +3500.
Notice how much more information is provided. The distance between two contour lines is 500 m and you can see how steep the slope is to the "river".
Most of this blog deals with mapping and rapid transit issues, particularly street railways and trolleybuses. I would like to step away for a moment from the rapid transit part and dealing with another mapping issue, mapping other worlds. Mars has always been interesting to me on account of the supposed canals. Perhaps Martians also had some form of rapid transit along the canals? At any rate, thanks to the internet and interesting map programs as GRASS 6.4.1 which does all sorts of hydrology and other operations, let us see what Mars has to offer?
The following source shots were probably unzipped from a NASA website by myself:
The map below was produced from a shape file of the Mar's surface. I produced a map in ARCGIS and then transferred the program to GRASS. The two points of observation are pointed out. One is in the center of a crater where one of the Rover modules landed in 2004. Its' approximate location is -260521.36, -87339.29. I did not get the exact location*. Notice the "river like" crack south of the crater that goes to the east. I also picked as a reference point -251316.35 and -1044693.55 which is sort of a projection of some kind near the south side of the crater..
As a experiment: What would a person at this two locations see on Mars? Here we are asking about visibility. Second, how would water flow in the "river" to the south of the crater? To answer this, we will use GRASS 6.4.1.
* The location of the rover landing is handled by a separate shape file and I will need to investigate this further. The coordinate system by default in ARCGIS and GRASS is not the same. I picked the rover location at he near center of the crater randomly since the surface appears to be relatively flat. The picture below comes from NASA. It shows sunset over the Gusev Crater which is the crater that is shown below that has a "river " extending from it's southern section. The river is called "Ma-adim Vallis".
In the map above, I used the GRASS contour generator. My range is from about +4000 m to -4000 m in 1000 m sections. Notice the river is stands out clearly from the surroundings. The colors are coded according to elevation. Essentially, this map is a elevation file that is coded according to altitude. This was done automatically by GRASS. Do you see the red circle disk with two projections on the east side near the "river" Ma-adim Vallis.. This high area will also be a frame of reference. What would an observer see at both locations if the observer is 1.5 meters high? This is the raster - terrain analysis - visibility sequence.
This is the "visibility" result from the small red disk like projection. The range is 200,000 meters.
I cannot explain why I got this triangular shape. When I do the analysis at above 200,000 meters, the system crashes completely. Perhaps this odd shape is due to a computer problem and not a visual result. The dot at the north point of the triangle is the frame of reference.
In the map above, the yellow-green triangle is the visibility from the center of the projection that has the yellow dot in the red disk. I do not know why I get such a pattern.
In the map below, the GRASS 6.4.1 hydrology program was used to indict flow areas downhill from a rainstorm. The program will ask you to supply two parameters or more dealing with the length of the vector produced and the number of "cells" that it covers. Here you will need to try your luck in case you are like me and do not know what you are doing.
The green lines are theoretical water flow if Mars had a rain storm. This was based on the elevation file provided. You can see the outline of the "river" and the outline of the crater. Notice that the walls of the river have the water flow but not the bottom of the "river" itself.
The above map was produced in GRASS 6.4.1 using the raster-hydration program dealing with water flow and is the same as the picture above except for different settings. You can see the shape of the Gusev crater and the area where the river is. The water flow is perpendicular to the river and not along it. The walls of the crater produce water flow also perpendicular to the walls.
And I almost forgot, here is the visibility at a random location near where the rover landed in 2004.
The red dot in the frame of reference in the Gusev Crater. Visibility extends only inside the crater, of course.
Notice at the right side of at the bottom of the crater there appears to be a projection of a low area which appears to be the beginning of the "river".
Another view of the Gusev Crater and Ma-adim Vallis River.
This map was produced in GRASS using the slope aspect. Various derivatives can be derived from the slope of the elevations. I believe this is a dxdy partial derivative.
Below is a map that used GRASS to produce contour lines at 500 m intervals from -4000 to +3500.
Notice how much more information is provided. The distance between two contour lines is 500 m and you can see how steep the slope is to the "river".
Tuesday, March 11, 2014
Another Possible Trolley Overhead Reminder in Brooklyn
In other posts regarding the South Brooklyn Railroad, I posted a track map showing that for a long time, the only crossing from west to east across Third Avenue in Brooklyn was a one track surface track parallel to 39th Street. This crossing under the overhead Gowanas Expressway was at grade level and connected with the yards at the waterfront. Most of the track of the South Brooklyn RR had trolley style overhead mounted either from the familiar trolley poles painted black or wooden troughs mounted under structures. I remember in the late 1970's at this location, over the track there was a inverted wooden trough with trolley wire in it. It extended only under the highway structure and did not protrude over the sides. Of course, at the ends of the trough there was no further trolley wire like in the entire New York State except for Buffalo. I believe this was the only location in New York City were trolley wire then existed over a track; except perhaps the Essex Delancey Street trolley terminal on the Lower East Side where the overhead may still exist over trolley tracks covered over with six decades of dust. At any rate, the track path crossing Third Avenue may have changed in the past few years as a result of closing of the Davidson's Pipe Yard and the building of Cosco at the former yard site west of that location near 39th Street. Take a look at the picture attached from Google Maps. Do you see the support brackets to the former wooden trough that contained the trolley wire? Notice that the track curves slightly. I remember that is crossed Third Avenue at right angles. Or are they just pipe supports?
What do you think? You are facing east towards the South Brooklyn freight yard between 3rd and 4th Avenues. This area is so rich in rapid transit history.
Please look at the roof of the highway. Notice the curved track. This is the only track connecting east and west sections of the railroad, even in the good days.
What do you think? You are facing east towards the South Brooklyn freight yard between 3rd and 4th Avenues. This area is so rich in rapid transit history.
Please look at the roof of the highway. Notice the curved track. This is the only track connecting east and west sections of the railroad, even in the good days.
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