# GMT: add lines to a map
**URL:** https://discourse.julialang.org/t/gmt-add-lines-to-a-map/123852
**Category:** Visualization
**Tags:** question, gmt
**Created:** [December 15, 2024, 4:29am UTC](https://discourse.julialang.org/t/gmt-add-lines-to-a-map/123852 "2024-12-15T04:29:26Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@George9000](https://discourse.julialang.org/u/George9000)
#### Post date: [December 15, 2024, 4:29am UTC](https://discourse.julialang.org/t/gmt-add-lines-to-a-map/123852/1 "2024-12-15T04:29:26Z")
After plotting a map region with `coast`, I’d like to add a series of lines. I’m unable to correctly specify the arguments for the `lines!` call. I’ve also tried giving the x and y as separate [long] and [lat] vectors to lines. Error thrown is shown in the expandable section below.
```julia
using GMT
function main()
coast(region=[-116 -71 39 49],
proj=(name=:Albers, center=[-96 39], parallels=[40 50]),
frame=:none,
resolution=:high,
area=250,
land="#2FD63E",
shore=:thinnest,
borders=((type=1, pen=:thin), (type=2, pen=:thinnest)),
title="",
show=true)
positions = mat2ds([-72 41
-114 46])
lines!(positions,
pen = (0.75, "#E71F1E"), show = true)
end
```
> **Error**
>
> ```julia
> julia> main()
> Error: /undefined in A
> Operand stack:
> 0
> Execution stack:
> %interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1974 1 3 %oparray_pop 1973 1 3 %oparray_pop 1961 1 3 %oparray_pop 1817 1 3 %oparray_pop --nostringval-- %errorexec_pop .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval--
> Dictionary stack:
> --dict:767/1123(ro)(G)-- --dict:0/20(G)-- --dict:75/200(L)--
> Current allocation mode is local
> Last OS error: No such file or directory
> Current file position is 175302
> psconvert [ERROR]: System call ['/Users/foouser/.julia/artifacts/0d9e7c35bc21411c7d9c194f790e30a95a4a5795/bin/gs' -q -dNOSAFER -dNOPAUSE -dBATCH -sDEVICE=bbox -DPSL_no_pagefill -dMaxBitmap=2147483647 -dUseFastColor=true '/var/folders/zf/rr083cw10cv4zl468c6lt5gm0000gn/T/GMTjl_foouser.ps' 2> './psconvert_49997c.bb'] returned error 256.
> ERROR: Something went wrong when calling the module. GMT error number = 79
> Stacktrace:
> [1] error(s::String)
> @ Base ./error.jl:35
> [2] gmt(::String)
> @ GMT ~/.julia/packages/GMT/r3nfS/src/gmt_main.jl:169
> [3] showfig(d::Dict{Symbol, Any}, fname_ps::String, fname_ext::String, opt_T::String, K::Bool, fname::String)
> @ GMT ~/.julia/packages/GMT/r3nfS/src/common_options.jl:4233
> [4] finish_PS_module_barr_last(d::Dict{Symbol, Any}, cmd::Vector{String}, fname::String, fname_ext::String, opt_extra::String, output::String, opt_T::String, K::Bool, P::Nothing)
> @ GMT ~/.julia/packages/GMT/r3nfS/src/common_options.jl:4581
> [5] finish_PS_module(::Dict{Symbol, Any}, ::Vector{String}, ::String, ::Bool, ::Bool, ::Bool, ::GMT.GMTdataset{Float64, 2}, ::Vararg{Any})
> @ GMT ~/.julia/packages/GMT/r3nfS/src/common_options.jl:4519
> [6] _common_plot_xyz(cmd0::String, arg1::GMT.GMTdataset{Float64, 2}, caller::String, O::Bool, K::Bool, is3D::Bool, d::Dict{Symbol, Any})
> @ GMT ~/.julia/packages/GMT/r3nfS/src/psxy.jl:361
> [7] #common_plot_xyz#858
> @ ~/.julia/packages/GMT/r3nfS/src/psxy.jl:13 [inlined]
> [8] lines(cmd0::String, arg1::Matrix{Float64}; first::Bool, kwargs::@Kwargs{pen::Tuple{Float64, String}, show::Bool})
> @ GMT ~/.julia/packages/GMT/r3nfS/src/plot.jl:615
> [9] lines!(arg1::Vector{Float64}, arg2::Vector{Float64}; kw::@Kwargs{pen::Tuple{Float64, String}, show::Bool})
> @ GMT ~/.julia/packages/GMT/r3nfS/src/plot.jl:630
> [10] lines!
> @ ~/.julia/packages/GMT/r3nfS/src/plot.jl:630 [inlined]
> [11] main()
> @ cardmap /Volumes/personal/2024_thomas_newsletter/cardmap/src/cardmap.jl:24
> [12] top-level scope
> @ REPL[6]:1
>
> julia> versioninfo()
> Julia Version 1.10.7
> Commit 4976d05258 (2024-11-26 15:57 UTC)
> Build Info:
>
> Note: This is an unofficial build, please report bugs to the project
> responsible for this build and not to the Julia project unless you can
> reproduce the issue using official builds available at https://julialang.org/downloads
>
> Platform Info:
> OS: macOS (arm64-apple-darwin23.6.0)
> CPU: 16 × Apple M3 Max
> WORD_SIZE: 64
> LIBM: libopenlibm
> LLVM: libLLVM-15.0.7 (ORCJIT, apple-m1)
> Threads: 1 default, 0 interactive, 1 GC (on 12 virtual cores)
> Environment:
> JULIA_EDITOR = hx
> JULIA_PKG_DEVDIR = /Volumes/work/julia/dev
>
> ```
---
### Author:  [@joa-quim](https://discourse.julialang.org/u/joa-quim)
#### Post date: [December 15, 2024, 12:38pm UTC](https://discourse.julialang.org/t/gmt-add-lines-to-a-map/123852/2 "2024-12-15T12:38:43Z")
When you used ‘show’ in the ‘coast’ command you finished the PostScript file. Don’t do that. The ‘show’ option is used only in the **last** command.
---
### Author:  [@George9000](https://discourse.julialang.org/u/George9000)
#### Post date: [December 16, 2024, 12:36am UTC](https://discourse.julialang.org/t/gmt-add-lines-to-a-map/123852/3 "2024-12-16T00:36:02Z")
Thank you!