# GMT.jl: How to specify several river styles e.g. in coast?

**URL:** <https://discourse.julialang.org/t/gmt-jl-how-to-specify-several-river-styles-e-g-in-coast/133834>\
**Category:** Geo\
**Created:** [November 12, 2025, 7:41pm UTC](https://discourse.julialang.org/t/gmt-jl-how-to-specify-several-river-styles-e-g-in-coast/133834 "2025-11-12T19:41:20Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![trg818](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/trg818/32/219149_2.png) [@trg818](https://discourse.julialang.org/u/trg818)\
**Post date:** [November 12, 2025, 7:41pm UTC](https://discourse.julialang.org/t/gmt-jl-how-to-specify-several-river-styles-e-g-in-coast/133834/1 "2025-11-12T19:41:20Z")

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Hi,  
basically, my question is how to translate the regular GMT coast options  
`-I0/thicker,lightblue -I1/thick,lightblue -I2/thin,lightblue`  
to the keyword argument style. I tried  
`rivers=(type=(0,1,2),style=("thicker","thick","thin"),color=("lightblue","lightblue","lightblue"))`  
but that doesn’t work; I get the error `pscoast [WARNING]: Representation of pen color (1/2/) not recognized. Using default.` and the rivers don’t appear at all.

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**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [November 13, 2025, 9:55am UTC](https://discourse.julialang.org/t/gmt-jl-how-to-specify-several-river-styles-e-g-in-coast/133834/2 "2025-11-13T09:55:49Z")

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I can only look at this by the end of afternoon but doesn’t this example help?

> **[Coastlines and borders](https://www.generic-mapping-tools.org/GMTjl_doc/tutorials/coast/coastlines/#example_4530462154225019163)**

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<div class="post-metadata">

**Author:** ![trg818](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/trg818/32/219149_2.png) [@trg818](https://discourse.julialang.org/u/trg818)\
**Post date:** [November 13, 2025, 10:51am UTC](https://discourse.julialang.org/t/gmt-jl-how-to-specify-several-river-styles-e-g-in-coast/133834/3 "2025-11-13T10:51:25Z")

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Yes, the borders example has the sort of syntax I needed. For the record, my working code is now

```julia-auto
rivers=((type=0,pen=("thicker",:lightblue)),(type=1,pen=("thick",:lightblue)),(type=2,pen=("thin",:lightblue))),

```

Thank you very much.

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<div class="post-metadata">

**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [November 13, 2025, 1:20pm UTC](https://discourse.julialang.org/t/gmt-jl-how-to-specify-several-river-styles-e-g-in-coast/133834/4 "2025-11-13T13:20:10Z")

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Good. And the syntax you tried first is logic too. Will try to implement it.