# Issue with the grid @earth\_relief\_03s

**URL:** <https://forum.generic-mapping-tools.org/t/issue-with-the-grid-earth-relief-03s/1371>\
**Category:** Q&A\
**Created:** [February 22, 2021, 11:39am UTC](https://forum.generic-mapping-tools.org/t/issue-with-the-grid-earth-relief-03s/1371 "2021-02-22T11:39:02Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![earthistic](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@earthistic](https://forum.generic-mapping-tools.org/u/earthistic)\
**Post date:** [February 22, 2021, 11:39am UTC](https://forum.generic-mapping-tools.org/t/issue-with-the-grid-earth-relief-03s/1371/1 "2021-02-22T11:39:02Z")

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Hello everyone,

I am trying to plot a map for a small region. Therefore, I include the grid @earth\_relief\_03s. I set my -R such that it is a multiple of 3 arc seconds. However, my map does not have a good resolution and when I run my script I get this warning:  
grdblend [WARNING]: File @N30E130. **earth\_relief\_15s** \_p.nc has different increments (0.00416666666667/0.00416666666667) than the output grid (0.000833333333333/0.000833333333333) - must resample  
grdblend [WARNING]: File @N30E130\*\*.earth\_relief\_15s\*\*\_p.nc coordinates are phase-shifted w.r.t. the output grid - must resample  
Why do I get a warning related to the grid earth\_relief\_15s when I defined the grid @earth\_relief\_03s?

This is my script:

#!/bin/bash  
gmt begin Sakurajima-image png  
gmt basemap -R130:28:15/130:51:57/31:27:15/31:47:12 -JM18c -Baf -B+t"Probe" -V  
gmt grdimage @earth\_relief\_03s -I+d  
gmt colorbar -DjTC+h+o-0c/19.5c+w8c/0.5c+ml -Ba500+l"Earth relief [m]"  
gmt coast -Slightblue -L+w5k+c10N+ab+o4c/1c+u --MAP\_SCALE\_HEIGHT=8p  
gmt inset begin -DjTL+w3c+o0.3c #-F+gwhite+pthin  
gmt coast -Rg -JG130.4696/31.7816/3c -Bg -Gwheat -SLightBlue -EJP+gdarkgreen  
echo 130.5012 31.394 \> frame.gmt  
echo 130.8787 31.394 \>\> frame.gmt  
echo 130.8787 31.8763 \>\> frame.gmt  
echo 130.5012 31.8763 \>\> frame.gmt  
echo 130.5012 31.394 \>\> frame.gmt  
gmt plot frame.gmt -W5p,red  
gmt inset end  
gmt end show

I would appreciate your help!

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**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 22, 2021, 1:12pm UTC](https://forum.generic-mapping-tools.org/t/issue-with-the-grid-earth-relief-03s/1371/2 "2021-02-22T13:12:45Z")

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Very likely because your region includes some marine part and the 03s, which are derived from SRTM data, only cover continental areas.

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<div class="post-metadata">

**Author:** ![earthistic](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@earthistic](https://forum.generic-mapping-tools.org/u/earthistic)\
**Post date:** [February 23, 2021, 12:03am UTC](https://forum.generic-mapping-tools.org/t/issue-with-the-grid-earth-relief-03s/1371/3 "2021-02-23T00:03:12Z")

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Thanks Joaquim for answering. Indeed! My region includes marine part. I tried with the grid @srtm\_relief\_01s and it looks good! The only problem is the “conflict” at the line of coast:

 ![grafik](https://canada1.discourse-cdn.com/flex047/uploads/gmt/original/1X/1c376abb78c83c3363fc1a04dc64105f14446790.jpeg)

Here without `-SLightBlue` in the command `gmt coast` […]:

 ![grafik](https://canada1.discourse-cdn.com/flex047/uploads/gmt/original/1X/6edc03dbc3234524d1d68281b76fbf2a58275fa5.jpeg)

Could you please tell me how can I change this blue color? How can I assign a different color for the sea region? Which parameter is it?

Thanks in advance!  
Best regards!

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<div class="post-metadata">

**Author:** ![PlanetGus](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/planetgus/32/303_2.png) [@PlanetGus](https://forum.generic-mapping-tools.org/u/PlanetGus)\
**Post date:** [February 23, 2021, 1:21am UTC](https://forum.generic-mapping-tools.org/t/issue-with-the-grid-earth-relief-03s/1371/4 "2021-02-23T01:21:41Z")

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`-SLightBlue` fills the “sea” region in “lightblue”  
`-S255/0/0` would fill it in red (RGB format)  
`-S#ffffff` would fill it in white (hex format)  
…  
GMT support different color formats 🙂

If you aim to change the background directly (from `grdimage` layer)

I’m not 100%, but this might help : [doc / color-parameters](https://docs.generic-mapping-tools.org/latest/gmt.conf.html#color-parameters)

```auto
gmt set COLORxxx (for everything)

```

or

```auto
grdimage [...] --COLORxxx (for this layer only)

```