# Challenges using grdimage
**URL:** https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783
**Category:** Q&A
**Created:** [August 16, 2020, 11:25am UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783 "2020-08-16T11:25:47Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Harold\_Ulotu](https://forum.generic-mapping-tools.org/u/Harold_Ulotu)
#### Post date: [August 16, 2020, 11:25am UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783/1 "2020-08-16T11:25:48Z")
Hello everyone,
I want to convert a grid ([JULY\_JUNE\_2018.zip](https://forum.generic-mapping-tools.org/uploads/short-url/lNPts153RWkyzHzbv5yoARKgQl5.zip) (273 Bytes) ) to image using `grdimage`. The grid is very small in size. I have attached the grid information here:
> JULY\_JUNE\_2018.grd: Title: Grid originally in Surfer 7 format
> JULY\_JUNE\_2018.grd: Command:
> JULY\_JUNE\_2018.grd: Remark:
> JULY\_JUNE\_2018.grd: Gridline node registration used [Cartesian grid]
> JULY\_JUNE\_2018.grd: Grid file format: sd = Golden Software Surfer format 7 (64-bit float, read-only)
> JULY\_JUNE\_2018.grd: x\_min: 34 x\_max: 35 x\_inc: 1 name: n\_columns: 2
> JULY\_JUNE\_2018.grd: y\_min: -8 y\_max: -4 y\_inc: 1 name: n\_rows: 5
> JULY\_JUNE\_2018.grd: z\_min: -0.0208080465946 z\_max: -0.00538880052983 name: z
> JULY\_JUNE\_2018.grd: scale\_factor: 1 add\_offset: 0
My aim is to produce something like this ([july\_june2018.zip](https://forum.generic-mapping-tools.org/uploads/short-url/m96hkUiKMTzZhAHJn04CHXTx8Hn.zip) (17.8 KB) ) but the output I am obtaining is very different. This is the output ([output.zip](https://forum.generic-mapping-tools.org/uploads/short-url/3jT0lYtj41p9yuT6VxNSe2aKnR7.zip) (40.6 KB) )
Here’s my MWE
> set ps=output.ps
> set grd=JULY\_JUNE\_2018.grd
> set cpt=a1.cpt
> gmt grd2cpt grd -Z \> cpt
> gmt grdimage grd -JM3i -R33.5/35.5/-8/-3.5 -C%cpt% -K \>ps
> gmt psxy g.txt -JM3i -W -Ba -R33.5/35.5/-8/-3.5 -Baf -O \>\> ps
> gmt psconvert ps -A -Tg
I am using Windows 7 64-bits and GMT6.0.0 for Windows OS.
Best regards,
Harold P
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### Author:  [@MarceloBanik](https://forum.generic-mapping-tools.org/u/MarceloBanik)
#### Post date: [August 16, 2020, 2:00pm UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783/2 "2020-08-16T14:00:22Z")
Hello Harold,
I could get something like your july\_june2018.png under linux using:
> ps=output04.ps
> grd=JULY\_JUNE\_2018.grd
> range=33.5/35.5/-8/-3.5
> cpt=a1.cpt
> gmt makecpt -Crainbow -T-0.025/-0.005/0.005 -D -Z \> $cpt
> gmt grd2xyz $grd | gmt surface -R$range -T0.1 -I1e-2 -Goversampling.grd
> gmt grdimage oversampling.grd -JM3i -R$range -C$cpt -Ba1f0.5 \> $ps
> gmt psconvert $ps -A -Tg
>
> 
> You could play with makecpt and surface options to adjust to your needs.
Best regards,
Marcelo
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### Author:  [@Harold\_Ulotu](https://forum.generic-mapping-tools.org/u/Harold_Ulotu)
#### Post date: [August 16, 2020, 2:04pm UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783/3 "2020-08-16T14:04:02Z")
Thank you @MarceloBanik, let me work on your solution. Thanks alot
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### Author:  [@Harold\_Ulotu](https://forum.generic-mapping-tools.org/u/Harold_Ulotu)
#### Post date: [August 16, 2020, 2:55pm UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783/4 "2020-08-16T14:55:49Z")
I have one more question @MarceloBanik , consider the image ([output04.zip](https://forum.generic-mapping-tools.org/uploads/short-url/u85tG4tWH4LVToL6XpPplWv71i2.zip) (87.8 KB) ). Is it possible to clip the region outside the boundary and set it to white color like this image ([output05.zip](https://forum.generic-mapping-tools.org/uploads/short-url/eIZDcs6Feamm4ui9eKHKhxonr3W.zip) (17.5 KB) ). Here is my code
> set ps=output04.ps
> set grd=JULY\_JUNE\_2018.grd
> set range=33.5/35.5/-8/-3.5
> set cpt=a1.cpt
> gmt makecpt -Crainbow -T-0.025/-0.005/0.005 -D -Z \> cpt
> gmt grd2xyz grd | gmt surface -R%range% -T0.1 -I1e-2 -Goversampling.grd=sf
> gmt grdimage oversampling.grd -JM3i -R%range% -C%cpt% -Ba1f0.5 -K \> ps
> REM Boundary
> gmt psxy g.txt -JM3i -W -Ba -R%range% -O \>\> ps
> gmt psconvert ps -A -Tg
Here is the Boundary file ([g.zip](https://forum.generic-mapping-tools.org/uploads/short-url/p08U7Qj6NxG6EkfOELZjlRPfD00.zip) (32.4 KB) ).
Again, Thanks alot.
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### Author:  [@MarceloBanik](https://forum.generic-mapping-tools.org/u/MarceloBanik)
#### Post date: [August 16, 2020, 3:31pm UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783/5 "2020-08-16T15:31:31Z")
you could use psclip to do it, on my linux, with:
> ps=output06.ps
> grd=JULY\_JUNE\_2018.grd
> range=33.5/35.5/-8/-3.5
> cpt=a1.cpt
> gmt makecpt -Crainbow -T-0.025/-0.005/0.005 -D -Z \> $cpt
> gmt grd2xyz $grd | gmt surface -R$range -T0.1 -I1e-2 -Goversampling.grd=sf
> gmt psclip g.txt -JM3i -R$range -K \> $ps
> gmt grdimage oversampling.grd -J -R -C$cpt -K -O \>\> $ps
> gmt psclip -C -K -O \>\> $ps
> gmt psxy g.txt -J -W -Ba -R -O \>\> $ps
> gmt psconvert $ps -A -Tg
that gives me:
Regards,
Marcelo
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### Author:  [@Harold\_Ulotu](https://forum.generic-mapping-tools.org/u/Harold_Ulotu)
#### Post date: [August 16, 2020, 3:34pm UTC](https://forum.generic-mapping-tools.org/t/challenges-using-grdimage/783/6 "2020-08-16T15:34:51Z")
Thanks alot @MarceloBanik for the support