Hi, this might be a naive question. But I would really appreciate it if someone can give me some hints. I was wondering, how do people usually plot the road network of a certain area in a map? Of course, certain coding function is called, but how? Thank you so much for your time and attention.
You can checkout GitHub - pszufe/OpenStreetMapXPlot.jl: Plotting functionality for the OpenStreetMapX.jl (Supports PyPlot.jl and Plots.jl with GR backend) that is the plotting frontend of https://github.com/pszufe/OpenStreetMapX.jl and uses data from OpenStreetMap.
@pszufe is an expert here, so he might have some more advice to share.
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OpenStreetMapX.jl allows you to process data in Open Street Map format (if you do not know how to get this data - it is described in project website). In particular a map in OpenStreetMapX.jl is represnted as a LightGraphs.jl graph.
For plotting you can use OpenStreetMapXPlot.jl - this is particularly useful for coloring routes or marking nodes on the map.
For interactive plotting the best tools out there seems to be LeafletJS. There is a Julia wrapper for it LeafletJS.jl but unfortunately it is unmaintained. What I usually do to process map data/analytics with Julia and if I need interactivity I use R-Leaflet integration.
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I think I have tried the OpenStreetMapx.jl, with my osm map data. But the data is too large, and the map finally obtained does not look very good. Someone told me that I need to leave out certain information from the data, and eventually I tried the other way around, by using a python package osmnx and then tried to call this python function from juilia. I’d prefer to mainly use Julia though.
Is there a standard way to process the huge osm file obtained from the open street map website?
Use the osmfilter utility first. I do vehicle traffic modellig/agent-based simulations and usually this command works for me:
osmfilter myfile.osm --keep="highway=motorway highway=motorway_link highway=trunk highway=trunk_link highway=primary highway=primary_link highway=secondary highway=secondary_link highway=tertiary highway=tertiary_link highway=unclassified highway=residential" --drop-author -o=myfileout.osm
After running this command your file will be around 6x smaller.
Of course you might need different filtering depending on your needs.
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@pszufe, One more question. How did you actually draw the edges, I mean, what’s the underlying principle? What I understand is that, if it’s a straight line, then it’s fairly easy to draw, because we basically can know the location of each point along this line. On the other hand, if it’s a curved line, then how did you know the shape / function of the line to draw it? I hope this is not a naive question to ask. I think this has something to do with the open street map data format.
Because I was thinking to model / visualize the movement of a vehicle along the road network. It would be much easier if each edge of the road network is a straight line, since in this case, I can just use linear function as the line/edge along any given two points. On the other hand, if it’s not a straight line, then things would be really complicated. I wonder how you handle this when you draw/plot the map.
@bsnyh - have a look at OpenStreetMapXPlot.jl source code. There are straight lines - just a lot of them. You can easily use OpenStreetMapXPlot.jl to render images of animation frames (with vehicle location), than you can use some other tool to combine the frames into a movie.
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so, all of them are straight lines, not some kind of curves? If so, then linear interpolation would work.
the frames you’re talking about, do you mean geo-dataframes?
- yes they are straight lines and you can use simple interpolation
- I mean simply animation frames, you could generate subsequent frames, save the to files and combine into a movie.
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julia> m=OpenStreetMapX.get_map_data("/home/Desktop/country.osm")
ERROR: MethodError: no method matching get_map_data(::String)
Closest candidates are:
get_map_data(::String, ::String; road_levels, use_cache) at /home/.julia/packages/OpenStreetMapX/lK8gq/src/parseMap.jl:82
Stacktrace:
[1] top-level scope at none:0
julia> using Pkg
julia> Pkg.installed()
Dict{String,Union{Nothing, VersionNumber}} with 7 entries:
"Juno" => v"0.5.3"
"OpenStreetMapX" => v"0.1.1"
"IJulia" => v"1.14.1"
"Plots" => v"0.22.5"
"Atom" => v"0.7.12"
"PyCall" => v"1.18.5"
"OpenStreetMapXPlot" => v"0.1.0"
julia> methods(get_map_data)
# 1 method for generic function "get_map_data":
[1] get_map_data(datapath::String, filename::String; road_levels, use_cache) in OpenStreetMapX at /home/.julia/packages/OpenStreetMapX/lK8gq/src/parseMap.jl:82
I’m using Julia 1.0.2. That might be the issue. In this case, I think I will need to install Julia 1.0.3, right?
No. It does not work for Julia version 1.0.3 either. This is strange.
| | |_| | | | (_| | | Version 1.0.3 (2018-12-18)
_/ |\__'_|_|_|\__'_| | Official https://julialang.org/ release
|__/ |
[ Info: Recompiling stale cache file /home/.julia/compiled/v1.0/OpenStreetMapX/rxMhI.ji for OpenStreetMapX [5c67c38e-c187-11e8-2be6-e3a6a3a5610f]
julia> using Pkg
julia> Pkg.installed()
Dict{String,Union{Nothing, VersionNumber}} with 7 entries:
"Juno" => v"0.5.3"
"OpenStreetMapX" => v"0.1.1"
"IJulia" => v"1.14.1"
"Plots" => v"0.22.5"
"Atom" => v"0.7.12"
"PyCall" => v"1.18.5"
"OpenStreetMapXPlot" => v"0.1.0"
julia> m = OpenStreetMapX.get_map_data("/home/devel/Desktop/sweden.osm")
ERROR: MethodError: no method matching get_map_data(::String)
Closest candidates are:
get_map_data(::String, ::String; road_levels, use_cache) at /home/.julia/packages/OpenStreetMapX/lK8gq/src/parseMap.jl:82
Stacktrace:
[1] top-level scope at none:0
I’m using Linux Ubuntu.
Generally, the error stack provide some good info on the error.
Closest candidates are:
get_map_data(::String, ::String; road_levels, use_cache)
So it suggesting that it need to take 2 strings as input. And going to the manual:
get_map_data
It needs the path and filename in 2 separate strings.
So probably something like this
m = OpenStreetMapX.get_map_data("/home/devel/Desktop","sweden.osm")
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What are the programming tools to use to combine them into a movie?
However, there is one thing that the stack trace does not show this time.
I have registered OpenStreetMapX as an official Julia package. In the registration process I was forced to change package ID to the one assigned in the registration process (package id in the form d3d4fdd0-c191-11e8-3358-a3629b56487d). Now I am getting feedback from people who have problem updating OpenStreetMapX.
I propose to remove the package and then install it again (maybe there is a more elegant solution but I do not know it):
Press ] to go to the package manager:
(v1.0) pkg> rm OpenStreetMapXPlot
(v1.0) pkg> rm OpenStreetMapX
(v1.0) pkg> add OpenStreetMapX
(v1.0) pkg> add https://github.com/pszufe/OpenStreetMapXPlot.jl
Now you should be able to work with the new API (that contains get_map_data(::String) function)
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Regarding the animation follow the steps
- Use
Plots.jlGR.jlbackend (this is the default inOpenStreetMapXPlot) because despite of long compilation time it has very fast rendering -
Plots.jlhas the functionsavefig()for rendering output to file (https://docs.juliaplots.org/latest/output/) - There is lots of software that is able to combine frame images, several years ago I have used ffmpeg and got excellent results (for example see this StackOverflow post)
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Perhaps you can use @animate or @gif to create animations more easily? Documentation here, and example code and resulting animation here.
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