Martian Cartography Options

[Phil Stooke]

Nice map! One comment - the position for Mars 2 should be 10 degrees further east. The position you show is the one reported as "where Mars 2 entered the atmosphere", but it was not travelling vertically to impact at that point, it was travelling to the east at a very low angle. The published locations of atmospheric entry and impact for Mars 6 make it very clear how this worked.

Phil

[djellison]

I especially love the color scale used - very nice - it retains that blue 'Oh..was this an ocean??' of the low altitude, but is clearly martian above it. LOVELY work.

D

[vikingmars]

CONGRATULATIONS Machi : how beautiful (and useful with all those elevations) !
(PS : I thought that the minimum depth in Hellas was -8,200 m, the USGS figure. Please, how did you get -8,530 m ?)

[machi]

Nice map! One comment - the position for Mars 2 should be 10 degrees further east. The position you show is the one reported as "where Mars 2 entered the atmosphere", but it was not travelling vertically to impact at that point, it was travelling to the east at a very low angle. The published locations of atmospheric entry and impact for Mars 6 make it very clear how this worked.

Phil

Thanks and thanks as well for info about Mars 2 (this will be repaired in pdf).

I especially love the color scale used - very nice - it retains that blue 'Oh..was this an ocean??' of the low altitude, but is clearly martian above it. LOVELY work.

D

Thanks! I used altimetry scale similar to that from maps in my old school atlas. I always liked these maps, so I think that's good idea.
And false color images from HRSC (with infrared as red) have similar colors in dependence on elevation. Deeper -> more atmosphere -> bluer, heigher -> less atmosphere -> redder.

CONGRATULATIONS Machi : how beautiful (and useful with all those elevations) !
(PS : I thought that the minimum depth in Hellas was -8,200 m, the USGS figure. Please, how did you get -8,530 m ?)

Thanks!

USGS figure is somewhat weird. Lowest point in Hellas Planitia was measured as -8197.51 meters below areoid. This is information from PEDR MOLA altimetry profiles. But in MEGDR maps, they have lowest point as -8208 meters. And MEGDR maps are constructed from PEDR profiles! I suppose, that this is some minor flaw in interpolation algorithm, which can did some errors (+/- 10 meters in some points). Or this algorithm works with slopes and can extrapolate possible peaks and depressions. I don't know.
Hellas' depth (-8530 meters) in the map is based on HRSC DTMRDR dataset. All data from this dataset are depicted as blue triangles (it is depicted in small legend down in the map). It's not so good visible in jpeg, it's better in pdf.
This dataset has digital terrain models with better local coverage and because of that often with better data for some regions. Authors of this dataset used data from MOLA altimeter as source of true elevations (they mapped elevations in DTM with help of MEGDR maps). Because they used not only same dataset, but also same areoid model, informations about elevation are (in theory) compatible between MOLA PEDR and HRSC DTMRDR.
This (-8530m) information looks weird, but I look at these DTM and MOLA detected lowest point as deep crater and in DTM data, smaller crater (undetected by MOLA) is in the middle of this crater, so this small crater in larger crater (which is in another crater - Hellas Planitia ) is actual deepest point on Mars.

[vikingmars]

This (-8530m) information looks weird, but I look at these DTM and MOLA detected lowest point as deep crater and in DTM data, smaller crater (undetected by MOLA) is in the middle of this crater, so this small crater in larger crater (which is in another crater - Hellas Planitia ) is actual deepest point on Mars.

Thanks a lot Machi for all your good explanations.
Did you make a more detailed hi-res elevation map of the inside of the crater with its small crater in its middle ? (please, see CTX image herewith, with the small crater marked with a yellow "+")

[machi]

"Did you make a more detailed hi-res elevation map of the inside of the crater with its small crater in its middle ?"
No, I didn't. It's possible (one can use local DTM in same way as global DEM), but my plan was to work only on global map of Mars.
But I can confirm, that your crater is that lowest place.
Here is part of browse image for h0532_0000 observations (shadow relief, BW image, color image) and DTM (with "cool" LUT) with dark (deep) crater.

Attached thumbnail(s)

 

[vikingmars]

Here is part of browse image for h0532_0000 observations (shadow relief, BW image, color image) and DTM (with "cool" LUT) with dark (deep) crater.

Thanks so much Machi
And about Olympus Mons ? I guess that your 21,281 m elevation now replaces 21,229 m as calculated by USGS ?
As for the crater in Hellas, could you, please, be so kind to show us a detailed map showing us where is the exact topmost place on the summit of Olympus Mons (between the main caldeira and Pangboche crater I guess...) ? Thanks a lot !

[machi]

Finally I did blog entry about my map.
I downloaded new improved version (26.6.2012) with corrected Mars 2 landing site and minor changes (more HRSC elevations, proper citations).
Map is now available as JPG (9MB) and as PDF (56MB).
JPG is alright, but I have some problems with PDF. It is too big for Google Docs, so it is not so easy to download this version. For example, Google writes, that it cannot check PDF with antivirus, because it's too big. But download link is despite this fully functional, and I don't know about any virus in my PDF .

Thanks so much Machi
And about Olympus Mons ? I guess that your 21,281 m elevation now replaces 21,229 m as calculated by USGS ?
As for the crater in Hellas, could you, please, be so kind to show us a detailed map showing us where is the exact topmost place on the summit of Olympus Mons (between the main caldeira and Pangboche crater I guess...) ? Thanks a lot !

I plan smaller blog entry about highest and lowest place on Mars, so patience!

[machi]

I have uploaded new (fifth) version of my topographic map of Mars (14 MB jpg):



Most of changes are related to the new names on Mars. Those names can be found on USGS page.

Here is map as PDF (57 MB!).

[TheAnt]

Thank you machi, wonderful map. I spent quite some time browsing around on it.
A map like this gives one really good context for what Mars is like.
And thank you for posting the old maps, some of them do indeed remind me of what Mars looks like in a telescope.
I have seen the bows and hook shape, though the map by Beer and Madler does not look much to how I remember Mars trough the ocular - that's one oddball.

Also I took a look of the highest and lowest points, so rest assured that your blog might be of interest.

[machi]

You're welcome!

But old maps are mostly posted by Phil, not by me!

[TheAnt]

Yes I felt it as a good time to make a nod to Phil and JohnVV while I were at it posting in this thread.

[machi]

I see that I promised post about lowest and highest points on Mars and I forgot to give a link.

[vikingmars]

I see that I promised post about lowest and highest points on Mars and I forgot to give a link.

Thanks a lot Machi. A long belief was that the topmost point of Olympus Mons was somewhere between the main caldeira and Pangboche crater. Now, thanks to you, we know now that it's right at Pangboche crater rim... What a BIG improvement you made on the global Martian topographic data.
Your work deserves (i.e. an "Olympus Games" GOLD medal !!!!)

[Lucas]

There is a new geologic map of Mars that was recently released by the USGS -- check it out!

http://pubs.usgs.gov/sim/3292/