Using Arctic DEM

I am trying to plot Arc DEM using GMT 6.0 installed using conda on Mac OS.
I downloaded 1 kilometer ArcticDEM Mosaic arcticdem_mosaic_1km_v3.0.tif file DEM. According to the web site Mosaicked DEMs are provided in 32-bit GeoTIFF format.

    1. This is file info:

gmt grdinfo arcticdem_mosaic_1km_v3.0.tif
arcticdem_mosaic_1km_v3.0.tif: Title: Grid imported via GDAL
arcticdem_mosaic_1km_v3.0.tif: Command:
arcticdem_mosaic_1km_v3.0.tif: Remark:
arcticdem_mosaic_1km_v3.0.tif: Pixel node registration used [Cartesian grid]
arcticdem_mosaic_1km_v3.0.tif: Grid file format: gd = Import/export through GDAL
arcticdem_mosaic_1km_v3.0.tif: x_min: -4000000 x_max: 3400000 x_inc: 1000 name: n_columns: 7400
arcticdem_mosaic_1km_v3.0.tif: y_min: -3400000 y_max: 4100000 y_inc: 1000 name: n_rows: 7500
arcticdem_mosaic_1km_v3.0.tif: z_min: -718.904541016 z_max: 5912.12158203 name: z
arcticdem_mosaic_1km_v3.0.tif: scale_factor: 1 add_offset: 0
+proj=stere +lat_0=90 +lat_ts=70 +lon_0=-45 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs

  1. I tried to convert it to GMT native netcdf format

gmt grdconvert arcticdem_mosaic_1km_v3.0.tif -V

  • This is new Netcdf file info

gmt grdinfo Title: Produced by grdconvert Command: grdconvert arcticdem_mosaic_1km_v3.0.tif -V Remark: Pixel node registration used [Cartesian grid] Grid file format: nf = GMT netCDF format (32-bit float), CF-1.7 x_min: -4000000 x_max: 3400000 x_inc: 1000 name: n_columns: 7400 y_min: -3400000 y_max: 4100000 y_inc: 1000 name: n_rows: 7500 z_min: -718.904541016 z_max: 5912.12158203 name: z scale_factor: 1 add_offset: 0 format: netCDF-4 chunk_size: 130,130 shuffle: on deflation_level: 3
SPHEROID[“WGS 84”,6378137,298.257223563,

  • I tried to make some changes:

gmt grdedit -R-180/180/60/90 -D+t"Arctic DEM Mosaic 500 m" -T -fg

and made a figure
gmt grdimage -Js0/90/12c/60 -R-180/180/60/90 -pdf arcticdem1km
The grid is distorted.

Any help is greatly appreciated.
Thank you,

The grid is a cartesian rectangle in projected meters. grdedit does not undo any projection. It only replaced -R-4000000/3400000/-3400000/3400000 with -R-180/180/60/90. You need to run grdproject -I to undo the projection you really want to obtain a lon-lat grid. See the grdproject documentation. Alternatively, if you are OK with making the map in the stereographic projection you can plot it using a cartesian scale and overlay a geographic basemap using the same projection.

Dear Paul,
Thank you!

Would you be able to provide a full set of commands to convert ArcDEM GeoTiF file to the same format as @earth_relief_02m grid with the same names for the variables?
For me it would be easier to follow grdproject documentation with a working example.
I am trying to use Arctic DEM instead of @earth_relief_02m grd to generate elevation map for Greenland for the following figure below.
Very best,

Don’t know if it’s really a good idea to convert to geogs since it cover a pole but it should be something like

gmt grdproject -I

Dear Joaquim,
Thank you.
I tried it and got the following message:
gmt grdproject -I
grdproject [ERROR]: Syntax error: Must specify a map projection with the -J option

What GMT version? With GMT6 it should not need a -J because your file is already georeferenced (I think).

Dear Joaquim,
It is gmt 6 GMT - The Generic Mapping Tools, Version 6.0.0 [64-bit] [4 cores]
installed using conda on Mac OS X

I’m not able to reverse project that grid with nothing. This is the hard GMT way but …

grdproject -I -Js-45/90/70/1:1 -V -C -R-180/180/0/90

even gdalwarp misses it

gdalwarp -t_srs "+proj=lonlat"

Dear Joaquim,
Thank you again.
I clearly have no chance …
I found this data-description info online
Very best,