# Gmt makecpt generate empty output

**URL:** <https://forum.generic-mapping-tools.org/t/gmt-makecpt-generate-empty-output/2619>\
**Category:** GMT.jl Q&A\
**Created:** [February 11, 2022, 11:41am UTC](https://forum.generic-mapping-tools.org/t/gmt-makecpt-generate-empty-output/2619 "2022-02-11T11:41:26Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![LongNguyen031017](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/longnguyen031017/32/1389_2.png) [@LongNguyen031017](https://forum.generic-mapping-tools.org/u/LongNguyen031017)\
**Post date:** [February 11, 2022, 11:41am UTC](https://forum.generic-mapping-tools.org/t/gmt-makecpt-generate-empty-output/2619/1 "2022-02-11T11:41:27Z")

</div>

Hi everyone,  
Now i try to use GMT 6.3.0 instead of older version (GMT 5.4) like before.  
However, there is some problem I facing certainly such a the output of makecpt is empty.

Furthermore, the way i create contour in GMT 6.3.0 is also not work as GMT 5.4.0

Here is my code:

```auto
gmt begin Subtropical_High png

gmt set GMT_THEME cookbook
gmt set FONT_ANNOT_PRIMARY +20p FONT_LABEL +20p  
gmt set MAP_TICK_LENGTH 4p MAP_TICK_PEN 3p MAP_FRAME_PEN 3p
gmt set PROJ_LENGTH_UNIT INCH FORMAT_GEO_MAP ddd:mm:ssF  

gmt makecpt -Cpolar -T100/200/10 > colors.cpt
 
gmt basemap -R100/185/0/45 -JQ180/9 -Bxa10Wf5W -Bya10Nf5N -BWeSn -X1 -Y2 

gmt coast -W1 -G200 -Di 

echo 100 50 20,5,black Period: 1977 - 2020 >TC 
echo 100 47 20,5,black Super Typhoon Cases: 181 >>TC 
echo 147 50 20,5,black Super Track Points (@~\263@~ 130 knots) >>TC 
echo 147 47 20,5,black for intensifying process only: 427 >>TC 

gmt text TC -F+f+jLM -N   

gmt plot WPSH_197901.txt -Ccolors.cpt
 
grdsample WPSH_197901.txt.grd -I0.01/1 -GWPSH_197901.txt.grd  

grd2xyz WPSH_197901.txt.grd >> WPSH_197901.txt.xyz

grdimage WPSH_197901.txt.grd -Csst1.cpt 

grdcontour WPSH_197901.txt.grd -CContour_SH.txt -W10/0/0/0 -A30+s30+k0/0/0 -
    
gmt psscale -Ccolors.cpt -R100/185/0/45 -JQ180/9 -DJCR+o0.58/0i+w6i/0.15i+e -L -By+lcm  

del MDR lon lat locationE locationW 
gmt end show

```

Here is file data

 ![image](https://canada1.discourse-cdn.com/flex047/uploads/gmt/original/2X/6/661bb9ebe4bf3d2e9d074041cbf35f1c192960d0.png)

Thank in advance for your caring and response.

---

<div class="post-metadata">

**Author:** ![Joaquim](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/joaquim/32/16_2.png) [@Joaquim](https://forum.generic-mapping-tools.org/u/Joaquim)\
**Post date:** [February 11, 2022, 12:02pm UTC](https://forum.generic-mapping-tools.org/t/gmt-makecpt-generate-empty-output/2619/2 "2022-02-11T12:02:37Z")

</div>

> [@LongNguyen031017](#):
>
> the output of makecpt is empty

From `makecpt` manual

**-H**

Modern mode only: Write the CPT to standard output as well [Default saves the CPT as the session current CPT]. Required for scripts used to make animations via [movie](https://docs.generic-mapping-tools.org/dev/movie.html) and [batch](https://docs.generic-mapping-tools.org/dev/batch.html) where we must pass named CPT files.

> [@LongNguyen031017](#):
>
> `grdcontour WPSH_197901.txt.grd -CContour_SH.txt -W10/0/0/0 -A30+s30+k0/0/0 -`

What is that trailing `-` doing there?

---

<div class="post-metadata">

**Author:** ![LongNguyen031017](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/longnguyen031017/32/1389_2.png) [@LongNguyen031017](https://forum.generic-mapping-tools.org/u/LongNguyen031017)\
**Post date:** [February 15, 2022, 12:12am UTC](https://forum.generic-mapping-tools.org/t/gmt-makecpt-generate-empty-output/2619/3 "2022-02-15T00:12:27Z")

</div>

I can solve my problem now. Thank you vey much.