when I plot a small area using SRTM1S the resolution is very good, but for large areas it becomes worse, and the size of the output file get smaller.
How to keep the highest resolution?
here the output images:
https://drive.google.com/drive/folders/12GxFPClmZTbBer1muqvczb8wJAdmqaKB
Please post the script you are using. There are several parameters that can affect output resolution.
gmt begin 1sec png
gmt grdimage 1sec.nc -JJ20c -Cearth -B -I+d
gmt end show
first: I downloaded some .jp2 files
second: converted them to .nc
then combined them using grdblend and get the final grid (1sec.nc)
finally: I tried to plot it using the attached script
I think I got it:
It is about the dimensions of the out image, when I increased the scale in -J option the resolution become better and the out file size increased.
Is that right?
I fail to understand why you list the first, second, third etc since GMT does all that under the hood. E.g.,
gmt grdimage @earth_relief_02m -Cgeo -B -R20/25/24/26 -pdf map
Changing the scale gives a larger plot but not improvement in resolution. Your post is a bit thin on the actual commands you run, so cannot help based on that.
Because for resolution 5m and better I got some errors. I tried to delete cache files and rerun but nothing changes. I do not know if GDAL affects that.
grdblend [NOTICE]: Remote data courtesy of GMT data server oceania [http://oceania.generic-mapping-tools.org]
grdblend [NOTICE]: SRTM15 Earth Relief at 02x02 arc minutes reduced by Gaussian Cartesian filtering (3.8 km fullwidth) [Tozer et al., 2019].
grdblend [NOTICE]: -> Download 60x60 degree grid tile (earth_relief_02m_p): S30E000
grdconvert [ERROR]: File C:/Users/Right was not found
grdconvert [ERROR]: Cannot find file C:/Users/Right
grdconvert [ERROR]: Option -G: Given more than once (offending option is -GC:/Users/Right)
grdconvert [ERROR]: Specify only one output file
grdconvert [ERROR]: Specify only one input file
grdblend [ERROR]: ERROR - Unable to convert SRTM file C:/Users/Right Click/.gmt/server/earth/earth_relief/earth_relief_02m_p/S30E000.earth_relief_02m_p.jp2 to compressed netCDF format
grdblend [ERROR]: Unable to obtain remote file @S30E000.earth_relief_02m_p.nc
grdconvert [ERROR]: File C:/Users/Right was not found
grdconvert [ERROR]: Cannot find file C:/Users/Right
grdconvert [ERROR]: Option -G: Given more than once (offending option is -GC:/Users/Right)
grdconvert [ERROR]: Specify only one output file
grdconvert [ERROR]: Specify only one input file
grdblend [ERROR]: ERROR - Unable to convert SRTM file C:/Users/Right Click/.gmt/server/earth/earth_relief/earth_relief_02m_p/S30E000.earth_relief_02m_p.jp2 to compressed netCDF format
grdblend [ERROR]: Cannot find file @S30E000.earth_relief_02m_p.nc
grdconvert [ERROR]: File C:/Users/Right was not found
grdconvert [ERROR]: Cannot find file C:/Users/Right
grdconvert [ERROR]: Option -G: Given more than once (offending option is -GC:/Users/Right)
grdconvert [ERROR]: Specify only one output file
grdconvert [ERROR]: Specify only one input file
grdblend [ERROR]: ERROR - Unable to convert SRTM file C:/Users/Right Click/.gmt/server/earth/earth_relief/earth_relief_02m_p/S30E000.earth_relief_02m_p.jp2 to compressed netCDF format
grdblend [ERROR]: Cannot find file @S30E000.earth_relief_02m_p.nc
grdblend [ERROR]: File @S30E000.earth_relief_02m_p.nc not found
[Session gmt (0)]: Error returned from GMT API: GMT_FILE_NOT_FOUND (16)
grdimage [ERROR]: ERROR - Unable to produce blended grid from C:\Users\RIGHTC~1\AppData\Local\Temp/=tiled_211_PX_a22328
[Session gmt (0)]: Error returned from GMT API: GMT_GRID_READ_ERROR (18)
[Session gmt (0)]: Error returned from GMT API: GMT_GRID_READ_ERROR (18)
[Session gmt (0)]: Error returned from GMT API: GMT_GRID_READ_ERROR (18)People never believe when we warn the to do not use spaces in file names (directories included)
I bet that you have a directory called “Right or-wrong”
Ok I will change it, thank you.