# How to find out sub-options under a module's option when using GMT in julia？

**URL:** <https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829>\
**Category:** Geo\
**Tags:** gmt\
**Created:** [March 30, 2023, 6:22am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829 "2023-03-30T06:22:05Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![dk-zen](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dk-zen](https://discourse.julialang.org/u/dk-zen)\
**Post date:** [March 30, 2023, 6:22am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829/1 "2023-03-30T06:22:06Z")

</div>

I’m new in GMT.jl. I follow the examples from [Tutorial in Julia — GMT 6.4.0 documentation](http://docs.generic-mapping-tools.org/latest/tutorial_jl.html), and make a geographic map with a image pasted. It works.  
However, I don’t know how to query all options and suboptions under a module (e.g. coast) , for precisely controling the elements in the diagram. The website above isnot written in detail.  
Any suggestions?

---

<div class="post-metadata">

**Author:** ![sidpku](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sidpku/32/45729_2.png) [@sidpku](https://discourse.julialang.org/u/sidpku)\
**Post date:** [March 30, 2023, 6:27am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829/2 "2023-03-30T06:27:30Z")

</div>

I usually use this page: [http://docs.generic-mapping-tools.org/latest/modules.html](http://docs.generic-mapping-tools.org/latest/modules.html)

you can find detail information about each function.

grdimage, makecpt, grd2cpt, mat2grid are mostly used.

---

<div class="post-metadata">

**Author:** ![dk-zen](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dk-zen](https://discourse.julialang.org/u/dk-zen)\
**Post date:** [March 30, 2023, 7:05am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829/3 "2023-03-30T07:05:02Z")

</div>

Thank you for your reply.  
For example, colorbar module, where can I find the description of the set of parameters in the ‘frame ’option?

```julia
GMT.colorbar!(pos=(anchor=:BC,size=(12.5,0.3), horizontal=true, offset=(0,1.0),triangles=true),
                color=CPT, 
                frame=(ylabel="Intensity",ticks=50,annot=50), 
                par=(FONT_ANNOT_PRIMARY=10,FONT_LABEL=8),
                savefig="imageonamap.png", 
                show=true)

```

---

<div class="post-metadata">

**Author:** ![sidpku](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sidpku/32/45729_2.png) [@sidpku](https://discourse.julialang.org/u/sidpku)\
**Post date:** [March 30, 2023, 7:22am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829/4 "2023-03-30T07:22:28Z")

</div>

refer to [http://docs.generic-mapping-tools.org/latest/colorbar.html](http://docs.generic-mapping-tools.org/latest/colorbar.html), you can find `-B` about frame

> **-B** [**p** | **s**]_parameters_

it’s in GMT style though. For example:

> GMT.colobar(B = “af”)

i think there is little information about parameters in julia style.

I’m also looking for such information, hoping others can help.

---

<div class="post-metadata">

**Author:** ![dk-zen](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dk-zen](https://discourse.julialang.org/u/dk-zen)\
**Post date:** [March 30, 2023, 7:39am UTC](https://discourse.julialang.org/t/how-to-find-out-sub-options-under-a-modules-option-when-using-gmt-in-julia/96829/5 "2023-03-30T07:39:03Z")

</div>

I have tried to use the approach `GMT.colobar(B = “af”)` , this way can quickly convert code in GMT to julia, but I encounter problems when plotting a map in map. Maybe I’m missing some information.