Mars heightfield parametric model.

Nasa, 7:35AM (GMT+1), "Touchdown confirmed for Mars Curiosity!!!"

To celebrate this little step I've made a GH definition that use NASA height data to build the Mars surface. It's not very advanced and it has some bottlenecks that could be great to solve.

Beginners could find interesting the method used to extract values from an image that uses a custom colour scheme to represent data (is not possible to extract hue values directly) or the simple displacement method used. These are the curves that follows the colors in the reference color gradient used by NASA in RGB (up) and HSV space:

You can see that there is no linearity or constant change in any channel, either RGB or HSV space.

There is some bottlenecks in the definition that you must take care about: data comparation component (Find Similar Members) and surface closest point (Surface CP). If you want to improve it, please do it, but send me the modified version ;)

Take care of not raise or push down the values in sliders without saving or know perfectly how much data your computer is able to calculate without memory problems. The main sample image is really big and the more resolution you set, more memory it will take to sample and calculate.

Thanks to Andrea Graziano for data links :)

And...Have fun!

Link to my blog post: Blurrypaths

Attachments:

Mars.zip, 4 MB

Replies to This Discussion

Permalink Reply by Yasser Hafizs on August 6, 2012 at 3:16pm

It's very cool, man!!

Thanks for share.

Permalink Reply by Ángel Linares on August 6, 2012 at 4:03pm

Thanks!

Permalink Reply by djordje on August 6, 2012 at 4:50pm

Great work you Spanish genius !

Permalink Reply by Vicente Soler on August 6, 2012 at 8:27pm

To solve the first bottleneck, when a mesh is created most of the time texture coordinates are added to the mesh that correspond to the UV values of the original surface. You can retrieve them using a scripting component (see attached def.).

To solve the second bottleneck, I googled for some info on the image. I found that if you go NASA's MOLA website, you can download .img files that can be converted to grayscale .png files. They also come with a .lbl text file with all the necessary info like the min/max values, projection type and so on. There's no need to use the "find similar" component if you use a grayscale image. Besides, the image you included was shaded (maybe you attached the wrong one) so it isn't suitable to create a relief map from it.

In other words, I didn't really solve your second bottleneck. I just used a more convenient data source.

Here's a screenshot with a mesh at 1/4 the resolution of the image source.

Since the attached definition contains the relief image, it's 26 MB.

EDIT:

Can't post files > 5 mb, so here's a link:

http://www.visose.com/Public/Documents/mars02.gh

Permalink Reply by Ángel Linares on August 6, 2012 at 10:11pm

Hi! Nice! Thanks for share! I saw the UV mesh evaluation component but I was not sure about the distortion applied to the texture space. Thanks for your solutions!

The image is the one I've found here: http://marsoweb.nas.nasa.gov/globalData/ , I'll try to generate the grayscale one with this new information you gave me.

The solution for your attaching problem is easy to solve: go to image sampler options and don't allow it to store file inside gh deffinition.

Thanks for playing!

Permalink Reply by Vicente Soler on August 7, 2012 at 5:47am

Unfortunately all those images are shaded, so they are not a good source to generate geometry from them.

About dettaching the image, i wanted the definition to just work when opened. I'll attach here a lower resolution version since the other link probably won't be working for long.

Attachments:

mars02_lowres.gh, 4.5 MB

Permalink Reply by Ángel Linares on August 7, 2012 at 4:15am

Hey! I've found what you told me :) http://pds-geosciences.wustl.edu/missions/mgs/megdr.html

I'm gonna play a little bit more this afternoom :)

Thanks for the advise!

Permalink Reply by Ángel Linares on August 7, 2012 at 7:40am

I've found these tools to convert label objects from http://pds-geosciences.wustl.edu/missions/mgs/megdr.html to JPEG, GIF or PNG files.

http://www.mmedia.is/bjj/utils/img2png/#howto

http://pds.nasa.gov/tools/nasa-view.shtml

Permalink Reply by Vicente Soler on August 7, 2012 at 7:43am

To convert the .img format to .png i used this.

Permalink Reply by Tim on December 25, 2015 at 5:33am

Hi Angel,

I hope you will get notified, considering the age of this post.

I've met some problems running img2png command prompt, it just doesn't work and how-to in the link doesn't mention anything specific about it.

Vicente's link is dead as well.

Edit:

I managed to convert an .img file to .png only after dumping it in the same directory (folder) with the .exe file.

Author only mentions:

Unzip the ZIP file and put img2png.exe, cfitsio.dll, several files with names ending with .RSX and img2png.ini somewhere on your computer (they must be placed in the same directory)

Which is useful only for specific files (not our case). It seems to be working and I'll keep playing with it and its results in gh definition.

Permalink Reply by Flora1.618 on July 23, 2016 at 3:59pm