# Load global relief using grdimage on general perspective projection

**URL:** <https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131>\
**Category:** Q&A\
**Created:** [August 2, 2024, 7:46am UTC](https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131 "2024-08-02T07:46:23Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![XiaoChenhan](https://avatars.discourse-cdn.com/v4/letter/x/aeb1de/32.png) [@XiaoChenhan](https://forum.generic-mapping-tools.org/u/XiaoChenhan)\
**Post date:** [August 2, 2024, 7:46am UTC](https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131/1 "2024-08-02T07:46:23Z")

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Hi,

I want to plot a circular relief map and show the elevation of one hemisphere. I found that when I use grdimage for global relief, the map won’t load if I use a global range i.e. -Rg option of grdimage

I have tried

```auto
gmt grdimage @earth_relief_15s -JH5c -Rg
gmt grdimage @earth_relief_15s -JG0/0/5c -Rg

```

But both didn’t work. Is there anyway I can still use -JG to map a hemisphere’s elevation? I do like its shape.

Great thanks.

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**Author:** ![yvonnefroehlich](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/yvonnefroehlich/32/5064_2.png) [@yvonnefroehlich](https://forum.generic-mapping-tools.org/u/yvonnefroehlich)\
**Post date:** [August 2, 2024, 11:31am UTC](https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131/2 "2024-08-02T11:31:32Z")

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Hello @XiaoChenhan  
If you download the `earth_relief` remote dataset for a global range with a resolution of `15s` (15 arc-seconds), this is 2.6 GB (please see the table at [GEBCO Earth Reliefs — Remote Datasets documentation](https://www.generic-mapping-tools.org/remote-datasets/earth-gebco.html#usage)). This may cause problems. I think a lower resolution should be sufficient for a global map in most cases. Can you please try using a lower resoultion and check if this works?

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**Author:** ![Esteban82](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/esteban82/32/54_2.png) [@Esteban82](https://forum.generic-mapping-tools.org/u/Esteban82)\
**Post date:** [August 2, 2024, 1:05pm UTC](https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131/3 "2024-08-02T13:05:36Z")

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Hi @XiaoChenhan

You can also NOT specified the resolution, and GMT will download the optimal resolution needed for your map based on it region and projection.

`gmt grdimage @earth_relief -JH5c -Rg`

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<div class="post-metadata">

**Author:** ![XiaoChenhan](https://avatars.discourse-cdn.com/v4/letter/x/aeb1de/32.png) [@XiaoChenhan](https://forum.generic-mapping-tools.org/u/XiaoChenhan)\
**Post date:** [August 2, 2024, 3:05pm UTC](https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131/4 "2024-08-02T15:05:54Z")

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I have downloaded the dataset of 15s for a global range already, but yeah it seems only when I don’t specific the resolution the map could load. The gmt reduced the resolution using gausian filter. Thank you very much for your advice.

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<div class="post-metadata">

**Author:** ![XiaoChenhan](https://avatars.discourse-cdn.com/v4/letter/x/aeb1de/32.png) [@XiaoChenhan](https://forum.generic-mapping-tools.org/u/XiaoChenhan)\
**Post date:** [August 2, 2024, 3:07pm UTC](https://forum.generic-mapping-tools.org/t/load-global-relief-using-grdimage-on-general-perspective-projection/5131/5 "2024-08-02T15:07:16Z")

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Thanks a lot, this worked well. I mean I wanted a high resolution but I guess you can’t have both large range and high resolutions.