Building Surface Topography Files - Revision history

Martin.turbet at 12:01, 3 April 2025

2025-04-03T12:01:54Z

2023-11-08T13:59:35Z

‎Getting topography and surface data

2023-10-27T22:39:55Z

‎Convert the data into a netcdf surface topography map

2023-10-26T18:12:07Z

2023-10-26T18:07:57Z

‎Using a new topography in the model

2023-10-26T18:02:45Z

‎Using a new topography in the model

2023-10-26T18:00:24Z

‎Convert the data into a netcdf surface topography map

2023-10-26T17:59:32Z

‎Getting topography and surface data

2023-10-26T17:59:00Z

2023-10-26T17:58:25Z

‎Getting topography and surface data

@@ Line 3: / Line 3: @@
 Surface topography maps are netcdf files stored in your /datagcm/surface_data/ repository. Such files contain information on terrain elevations, as well as albedo and thermal inertia.
-As a reminder, our database of surface topography files is available here: https://web.lmd.jussieu.fr/~lmdz/planets/LMDZ.GENERIC/datagcm/surface_data/
+As a reminder, our database of surface topography files is available here: https://web.lmd.jussieu.fr/~lmdz/planets/generic/datagcm/surface_data/
 == Getting topography and surface data ==
 A few options to do that:
-* use existing topographic data for solar system objects. We have already formatted the data for most solar system objects, so please ask someone in the team if your topography map is not already here:  https://web.lmd.jussieu.fr/~lmdz/planets/LMDZ.GENERIC/datagcm/surface_data/
+* use existing topographic data for solar system objects. We have already formatted the data for most solar system objects, so please ask someone in the team if your topography map is not already here:  https://web.lmd.jussieu.fr/~lmdz/planets/generic/datagcm/surface_data/
 * use your own data files

@@ Line 34: / Line 34: @@
      for j in range(0,image_height,1):
          if(pix[i,j][0]<1. and pix[i,j][1]<1. and pix[i,j][2]<1.):
-             topography_data[i,j]=5.
+             topography_data[i,j]=5. # in km
          else:
-             topography_data[i,j]=0.
+             topography_data[i,j]=0. # in km
 # Here we write the topography map into an ascii file

@@ Line 59: / Line 59: @@
 <syntaxhighlight lang="python">
 from    numpy import *
 import  numpy                 as        np

@@ Line 11: / Line 11: @@
 * use your own data files
-You can also derive data files by digitalizing color maps. See below an example:
+You can also derive data files by digitalizing images. See below an example:
 [[File:rico_topography.png|thumb|rico_topography.png]]

← Older revision		Revision as of 18:07, 26 October 2023
Line 130:		Line 130:
	== Using a new topography in the model ==		== Using a new topography in the model ==

−	Now that you have your netcdf surface topography file ready, simply add the surface topography netcdf file in your datagcm/surface_data/ directory, and then follow the tutorial here: https://lmdz-forge.lmd.jussieu.fr/mediawiki/Planets/index.php/Advanced_Use_of_the_GCM	+	Now that you have your netcdf surface topography file ready, simply add the surface topography netcdf file in your datagcm/surface_data/ directory, and then follow the tutorial here: https://lmdz-forge.lmd.jussieu.fr/mediawiki/Planets/index.php/Advanced_Use_of_the_GCM#How_to_Change_the_Topography_.28or_remove_it.29

← Older revision		Revision as of 18:02, 26 October 2023
Line 130:		Line 130:
	== Using a new topography in the model ==		== Using a new topography in the model ==

−	Now that you have your netcdf surface topography file ready, simply follow the tutorial here: https://lmdz-forge.lmd.jussieu.fr/mediawiki/Planets/index.php/Advanced_Use_of_the_GCM	+	Now that you have your netcdf surface topography file ready, simply add the surface topography netcdf file in your datagcm/surface_data/ directory, and then follow the tutorial here: https://lmdz-forge.lmd.jussieu.fr/mediawiki/Planets/index.php/Advanced_Use_of_the_GCM

@@ Line 59: / Line 59: @@
 <syntaxhighlight lang="python">
 from    numpy import *
 import  numpy                 as        np
@@ Line 67: / Line 70: @@
 # 1. WE GET THE SURFACE TOPOGRAPHY DATA
 nc = xr.open_dataset('surface_mars.nc',decode_times=False) # can be any netcdf file (e.g. start/startfi.nc files)
 # 2. WE READ THE VARIABLES
@@ Line 83: / Line 84: @@
 # LOOP TO MODIFY THE VARIABLES
 for i in range(0,len(lat),1):
      for j in range(0,len(lon),1):
          new_elevation[i,j]=max(elevation[i,j],-3.9) # here you put whatever you want ; in this example, we take the (MOLA) topography of present-day Mars and modify it to fill the topographic depressions with an ocean at an altitude of -3.9km
          new_albedo[i,j]=albedo[i,j] # here you put whatever you want
-         new_thermal_inertia[i,j]=thermal_inertia[i,j] # here you put whatever you want
+         new_thermal_inertia[i,j]=thermal_inertia[i,j] # here you put whatever you want"""
 # SANITY CHECK PLOTS

← Older revision		Revision as of 17:59, 26 October 2023
Line 50:		Line 50:


−	This requires the use of the PIL library.	+	This requires the use of the PIL library, and the rico_topography.png file.

	== Convert the data into a netcdf surface topography map ==		== Convert the data into a netcdf surface topography map ==

@@ Line 12: / Line 12: @@
 You can also derive data files by digitalizing color maps. See below an example:
 <syntaxhighlight lang="python">
@@ Line 47: / Line 49: @@
 </syntaxhighlight>
 This requires the use of the PIL library.

@@ Line 46: / Line 46: @@
          print("{:12.5e}".format(topography_data[image_width-1,j]),file=f1,end='\n')
 </syntaxhighlight>
 This requires the use of the PIL library.
 == Convert the data into a netcdf surface topography map ==