More Goodies

The internet archive now has full editions of Ares Magazine up. Issue 16 has a couple of articles referenced by Winchell Chung over on Atomic Rockets. Page 1-7 is, “Galactic Empires,” by Robert Freitas. On page 15 is another article by Dr. Freitas, “Crimes, Crazies and Creole Cookery,” which begins, “Consider a family having a picnic in a park. The blanket is spread in a large, open clearing and the food unpacked. Ants begin to appear, innocently searching for nourishment. One of the children tracks them down to their anthill, pours a pint of kerosene down the hole and ignites it. The insects are destroyed. The picnic continues uninterrupted.” Winchell Chung’s  always useful Atomic Rockets site had a nice discussion on alien technology.

“The second thought is that such technology can be very very dangerous. Especially if the aliens seem more technologically advanced that you are. Even if the items are not deliberately booby-trapped, monkeying around with, say, alien nanotechnology could result in the lab and most of the surrounding terrain melting into grey goo. As an analogy, imagine an 1850′s Victorian Era scientist dismantling a live nuclear reactor trying to figure out how it works. Radioactivity hadn’t been discovered yet, much less nuclear fission. So they would be at a loss trying to explain the disaster that happened after they removed all the nuclear damper rods for closer examination.”

Given the trouble that scientists with a much higher level of technological knowledge got into, I wouldn’t want to be one of those Victorian scientists. The Straumli Realm in Vernor Vinge’s “A Fire upon the Deep” is one possible example of how that could go with a rather more Clarkian technology. In Rocketpunk Manifesto(bookmark that blog), Rick Robinson extrapolates the growth of population in space based upon a few basic assumptions. Namely, six people in permanent residence in 2009, a 4% growth rate and compound growth. He then extrapolates back: three people in 1991, 1 person in 1963. I can quibble about how well these actually fit reality. How many people were in space full-time in 1963. During the shuttle years, no more than eight people could go up, typically for no more than two weeks, seldom more than four times a year; this comes to 64 person weeks, or just over one person in space year round. Including Russia might have doubled that number, but not much more. I figure the actual equivalent number of person-years in space didn’t significantly exceed one until after Mir went up in 1991. I also have to quibble about his assumptions regarding the inflection point for space population. I agree that logically all exponential growth patterns have ultimately to be logistic, that is to say as some carrying capacity is approached, growth must necessarily slow. However, I’m not convinced of the absurdity of 1.4 billion people in space in 2500 or possibly even 3.5 trillion in 2700(that last strains my credulity, but more because I have trouble thinking of that many people than any rational objection). Although life in space is intrinsically expensive, wealth represented by energy and raw materials. Let’s look at energy. Solar energy in this case. From Wikipedia world energy consumption in 2008 was 143.851 PWh/yr(5.17864 x 10²⁰ J/yr) including solar energy and whatever else. The total luminosity of the Sun(from Wikipedia) is 3.839×10²⁶ W or (1.211 x 10³⁴ J/yr). This allows for an upper limit population on the order of 20 trillion times the supportable population in 2008. I’ll assume that the actual supportable population of the Earth in 2008 was greater than the actual population of about six and a half billion, I’ll also assume that the energy resource requirement in space is close to a million times what is required to support a person on Earth. That gives us a supportable population of about 156 quadrillion people. The scale of the Solar system sets a high standard for absurdity. With my quibbles in mind, it still makes an interesting sort of model for future space development. About 30 people in space by 2050. By 2101 the model predicts 220 people in space and over 10,000 by 2200.

As Mr. Robinson says, when building a Future History, it pays to have a fairly wide cushion of “Vague Era” between the present and your storied future to prevent it from turning into an Alternate Future too soon. This model definitely works for that. Asking questions about things too near in the future, or answering them, pretty much sets the writer up for a fall unless the person isn’t actually a science fiction author but a prophet. For myself, at the moment I’m focussing on being a science fiction writer, so hopefully I’ll be forgiven for letting the blog slide a bit. The way things go around here sometimes, you may not even notice my absence.

See you soon,
The Astrographer

Goodie Bag

The time has come to post some links. Some may be useful, others may just be fun. Still others may just be symptomatic of mental illness on my part .

http://blenderartists.org/forum/showthread.php?77622-NASA-s-quot-Botany-Bay-quot&s=b294c9e5d14b9c05eb0e0af72ccb6198

Rocketry and Spacecraft

The first thing in the Rocketry and Spacecraft department is bad news and related whinging. The NTRS site has been down for quite awhile. Supposedly in response to the recent espionage charges against Bo Jiang. Seems like a lot of the stuff from the sixties, at least, should have been cleared for ITAR a long time ago. I think its more of an opportunity action by people hostile to open government. Hopefully it’ll all be back up on wikileaks pretty soon .

Speaking of Wikileaks, they have the full text of Appendix 6 of the NASA Exploration Systems Architectural Study with lots of juicy details on the various launch vehicle alternatives that were looked at in the study. I especially appreciated the, presumably accurate, weights and measurements of the Atlas and Delta evolution phases. It’s a welcome and useful addition to the rest of the report openly published, here. I’m a fan of the nasaspaceflight.com site, and I’d love to get an L2 account if I ever have that kind of money to spare, but I think this is exactly the sort of information that NASA should have been publishing openly on its own…

Pretty clearly, even with greatly disparate propellant densities, tank masses cluster pretty well around the MTank = 10.41 * (VTank)^0.75 line(Thanks to http://www.alternatewars.com/). I use Pietrobon’s exponent of 0.848 largely on faith, ’cause I haven’t actually checked his line against this…

Alternate Wars has a nice set of tutorials on the design and modeling of imaginary rockets. The tutorials are intended for modders of the Kerbal Space Program game, but the information on creating 3d rocket models in Blender and figuring out propellant and tank weights is useful to anyone with an interest in this sort of thing. Previously, I used the tank sizing rules from Steven Pietrobon’s Analysis of Propellant Tank Masses(grab that before some Congress-critter decides its a security risk and disappears the thing). One thing I hadn’t been too sure about was how tank masses would vary with propellant density. Pietrobon was looking specifically at hydrolox applications, so I didn’t know how that would vary with kerolox or other propellant combinations. The picture to the left, which I took from Alternate Wars has alleviated my confusion.

In a loosely related vein, this thread has some more pictures of the ‘realistic’ Star Trek DY-100 posted by Winchell Chung(right purdy, those). Samples shown above and to the right. How cool is that? I’m feeling a need to build spaceships! Future post idea!

Stars and Planets

Landon Noll posted a nice table showing stellar parameters by HR  and Luminosity class. I like it. It’s a good expansion upon the similar table in 2300AD. Also like the 2300AD table there’s a clear problem with this kind of chart: try as I might, I can’t find any giant stars with masses similar to Sol. This is kind of an argument in favor of the GURPS Space 4th ed. rules for generating stars that start with mass and age and determine HR spectrum and Luminosity class from that. I still like this kind of chart and I’ll likely be using it frequently. It’s just necessary to use a bit of care when considering the parameters of non- main sequence stars.

Even more useful to me was this page by Larry Bogan. I already had the formulae for determining the luminosity of a star from its temperature and radius(and other combos of those values), but the formulae for Color Index and Bolometric Correction are sure nice.

Electric History

Not that I haven’t had algorithmic simulation of social attributes swimming around in the back of my mind since long before I was inspired to make this post, by a post on Sword vs Dagger about population distribution, but it has been bubbling up a lot lately. Back in the ’80s I played a game on my Amiga called Balance of Power. This was a game about playing power politics without immolating the Earth in nuclear fire! I usually failed on both counts… In spite of that, I was fascinated by the idea of simulating global politics on a computer. I’ve been wanting to do something like GDWs Great Game(Check out the map) for two centuries now.

The way things in life seems to focus on an idea makes me believe in synchronicity. Although, as I’ve said, this idea has been at the back of my head for a long time, but just lately it seems to have come to a head. So I was trawling Atomic Rockets(Winchell Chung again…) looking for stuff on interstellar colonization. This leads me on into his history stuff: Future History, Alternate History and (especially)Modeling History. In the last, Chung brings up Balance of Power and a book detailing something about the internal algorithms of the game. Well after a bit of digging I find a copy of that book right here on the internet. Posted by the author no less.

In another tab, I’m looking at SFRPG forum, mostly to see if Constantine Thomas has anything new going on. There I find a thread on Taxonomies of Governments. I think it’s about time to get my thoughts together and write a post on this particular subject…

GIS, Terrain Generation and Visualization

Another field that needs a bit of love lately. I haven’t done much in this area, but I did run across a couple of good bits. Genesis 4 is a terrain visualization tool that I had a good deal of interest in awhile back, but not enough to loosen the clawlike grip I maintain on my not terribly heavy wallet. Now it’s altogether free. Just look for the registration name, key and validation on the linked page. I’ve messed around a bit with Landformer, but this is nice to see. On the down side, it probably doesn’t bode well for the financial health of the producer or the programs future updatage. Always a cloud…

Next time I boot up Windows, I’ll also try out Nem’s Mega 3D Terrain Generator. Should be good for a lark at least.

Thank you for reading,
The Astrographer

Using the Route Finder in chView2

Our first attempt at a route between Sol and 61 Cygni…

The Route Finder Report has always been one of my favorite tools in chView2. Even with the distance links displayed, it can be very hard visually to ascertain a good route between two stars in a three dimensional display. Route Finder makes that considerably easier. The recent addition of a textual report describing the legs of the route with actual leg distances and total distance travelled has made it even more convenient and useful to me.

The purpose of Route Finder is to find the shortest path between two stars consisting of a number of legs, each of which begin and end at an existing astronomical object and are of some limited length. This is the model of Traveller’s Jump Drive, which is capable of 1, 2, 3, 4, 5, or 6 parsec jumps between stars(although in some versions jumps beginning or terminating in deep space may or may not be allowed), my own version of the Alcubierre Warp Drive in FTL mode and apparently C.J. Cherryh’s choice of FTL drive(I don’t recall the exact parameters of that drive, or the name of it, but I do remember that it was restricted to travel along specific routes). This involves a percolation model of interstellar travel where the allowed route between two points may be quite convoluted and considerably longer than the direct path seems to indicate. If the length of the longest allowed leg is less than some critical percolation value, there could even be objects on the map that are mutually unreachable.

One feature, in fact, that I’d like to see added to chView2, eventually, is a tool to determine that smallest critical leg size limit such that all objects on the map are reachable from all others. Because the maps are necessarily smaller than the total extent of the galaxy, it may be a necessary to limit the, “No Orphans,” requirement to some extent smaller than the entire map, as actual routes may exist between objects near the edge that pass through objects that aren’t represented on the map.

Links tab in Preferences window…

With all that in mind, let’s look at how one uses the Route Finder Report.

This requires some set up. First open the Links tab in the Preferences(View>Preferences…:Links tab). Make sure that Show Links and Show Numbers options are both checked, if not click any checkbox without a checkmark to select the option. Now select the numbered textbox at the very bottom middle of the window right above the “OK” button. This is the maximum allowable link between two stars. In my

own science fictional universe the maximum distance that the Warp Drive can travel between two stars is about nine light years, so I enter “9.0″. That sets the maximum leg length that the Route Finder uses. Now we select the two objects between which we wish to travel. Simply click on the first object to select it, then, while holding down the shift key on your keyboard, click on the other end of your desired route. The order of selection

Our first attempt at a route between Sol and 61 Cygni…

doesn’t matter as the route can be considered symmetrical. For the example, I will select Sol and 61 Cygni A in my localSpace.chv.xml map. With the two termini of your route selected, simply go to the Report menu and select the Route Finder item. From that we get the Route Finder Report shown to the left.

What we see on the report is a route that leaves Sol, passes through BL Ceti, SO 0253+1652, GX Andromedae, Kruger 60, Gliese 725 and Ross 248, ending finally, about 50.9 light years later at 61 Cygni. How cool

The route on the map. Along with everything else…

is that? The trouble is, as anyone who’s ever wondered about the sanity of their GPS knows, this kind of algorithm doesn’t always find the absolute best route. So, just as a sanity check, let’s have a look at the route on the map(image to the right).

As you can see from the figure, even with the stars nicely picked out and even with the termini circled, it isn’t necessarily easy to see the route among all the clutter of a densely-packed starmap. ChView2 is capable of helping with that. First go the menu and select View>Show only selected. This

A better view of the route. A key principle of cartography is to show only the useful information.

will show all of the objects that were selected by the Route Finder and remove extraneous objects from the view. This is only temporary, after you’re done examining the route you can select View>Show All to return the view to normal. In order to maximize the clarity of the view, I also rotated the view orientation a bit. This, much clearer view of the route is shown to the left.

On visual examination, that clump of linked stars at the upper right end of the map is a bad sign. The algorithm is usually pretty reliable, but sometimes it breaks, and this may be one of those times. Looking at the report again, we see that from GX Andromedae the route snakes through Kruger 60 all the way out to Gliese 725 and then way back to Ross 248 before finally ending up at 61 Cygni. In this case, the roughly seven lightyears of the direct route from GX Andromedae is obviously shorter than 4.9 lightyears to Kruger 60, then over six out to Gliese 725, then over eight lightyears back to Ross 248 and then another over five and a half lightyears out again to 61 Cygni. Yeah, that ain’t right. This is instructive, though, both to what a bad route looks like and how to fix it.

First let’s find the route from GX Andromedae to 61 Cygni. That’s a direct route and

The last bit of the route. Much better.

about seven light years as shown to the right. Not bad at all…

Now we use Route Finder to calculate the route from Sol to GX Andromedae. Whoa! All over the place and with a distance of over a hundred light years. That’s ugly bad.

I’m not sure what’s going wrong here. If I ever figure it out, I’ll try fixing it. The best way to fix this will be to use the route to GX Andromedae that was calculated as part of the route from Sol to 61 Cygni and use a calculator to figure out the distance.

The stars of the best route hand-selected.

Sol <-> BL Ceti (8.73 LY), BL Ceti <-> SO 0253+1652 (8.03 LY), SO 0253+1652(8.79 LY) for a total of about 25.55 LY. Now our last check gave us a direct route from GX Andromedae to 61 Cygni of about 7.08 LY. Adding those together, we get a total distance of about 32.635 LY. The resulting route is shown in the image above and to the left. After a bit of jiggering with Open Office, I was able to create the following official-looking Route Finder table.

I really need to get rid of circled-R symbol. For some reason, I thought it was cute, now it just seems kind of stupid…

Again, if I can ever figure out what’s gone wrong here, I’ll try to fix it, but I’m still mystified. I’d certainly welcome advice. It seems to happen less frequently with smaller maps and a lot with larger maps, and as shown in the example, it’ll work fine over some parts of the route and blow up even worse over others. The code is zipped into the jar file if anyone would like a look…

I hope this has been useful, and I would love some help with this,
The Astrographer

Some Progress With ChView 2

A close-up of the calculated route with a conveniently easy-to-read orientation.

This is just a quick aside to let you know I’ve made a tiny bit of progress with ChView 2. The current version now shows leg distances and the total distance travelled in the Route Finder Report. With this, I can consider the Route Finder complete for the moment. Down the line, when I feel up to it, I intend to add the ability for the Route Finder to create a properly marked, “route object,” as well, but that will have to wait till I feel competent to work on that.

The original link connects to the updated version, and for convenience I provide a link here as well.

The improved report with distance information. I guess I could have rounded off the distances, but I didn’t.

Strangely enough, I find this kind of information terribly useful. So I added it.

Hopefully, you will find the added information useful, or at least interesting as well.

Thank you for your attention,
The Astrographer

More on the Three-D Starscape

In my previous post I promised to share my modification of ChView2 given permission from the original authors Joseph Jaquinta and Ben Lin. I have that permission, so here it is. Let me know if that link fails. I’ve never done anything serious with Google Sites, but I needed some way to get that up in spite of WordPress’s refusal to support jars. I’ve tested it a bit from my own computer and it seems to work, but I’m the owner of the site, so… Who knows?

If the link does work, then, as soon as the file finishes downloading, you should be able to double-click on the jar to bring up the program. In my previous post, I described how to create a sort of 3d compass rose in chView 2. Those instructions should still work just fine, although as you can see the program has gone through some alterations.

The slider bar for controlling the screen orientation.

The most immediately apparent change is in the orientation controls. I got rid of a button, added some text entry fields and, hopefully made the interface a bit more useable. At least for me. The zero button is a bit of a lie. It does set the rotation around the Z and X axes to zero but it sets the rotation around the Y axis to 180 degrees. The rationale between that set of rotations is that the positive Y-axis will be toward the top of the screen, the positive X-axis will be to the right and the Z-axis will point out of the screen, a familiar orientation. This is apparent if you saved a copy of the compass rose from last post(I actually have a saved file for the compass rose, here). Using the text entry fields you can set the rotations to one-degree precision. Once you set the fields to the desired rotation, hit the “Set” button and the screen will change to that orientation.

The Route Finder is a work in progress, but I have added a textual list of stars visited to the the output. I’m proud of that one…!

The Route Finder in action!

 

Local space. Right at the edge of usefulness…

Although I’m very proud of the small modifications I’ve made to the interface of this excellent program, they were only possible because of the excellent foundation that Mr Jaquinta and Mr Lin have laid. I only point them out here because I have grown somewhat dependent on those small modifications. I hope that they will, in some small way, enhance the usefulness of this marvelous program. I also hope that as my skills grow I will be able to make greater enhancements to the program.

Just to give you something to play with, I ran Extended Hipparcos and RECONS data taken from Constantine Thomas’s Stellar Mapping page through Excel to create a file of the stars within fifty light years of Sol(here).

Now go make star maps!
The Astrographer

 

Mapping the Stars

Originally, this was going to be a post on populations inspired by this post on Sword vs Dagger. Unfortunately, that has expanded, so far into about three posts. This will be one of those posts, although only tangentially related.

I’m going to speak today, as the title implies, of the mapping of stars. My tools will be the Extended Hiparcos Catalog Search Page, and ChView2. For further information on the use of the Hiparcos search page, look at Stellar Mapping and How to Make Your Own Stellar Database by Constantine Thomas. Some information on Chview2 may be found at Solstation, but it’s not terribly well documented. For the most part its a pretty simple app, and a lot of the instructions for the original ChView would be applicable. It’s a dandy little app, and very useful, but it still has a few bugs. I’ll try to help my gentle reader over those.

The empty main screen of ChView 2.

We’ll start simple and work our way up. Once you have a copy, double click on the chview2.jar. Our introductory project will be to make a sort of compass rose. This will introduce most of the basics needed for using ChView2 for starmapping.

Right click anywhere in the main view window(the black area at the bottom of this

The screen for editing fixed objects(in our case, generally, stars).

picture), to bring up a contextual menu. Select “Add Fixed Point” from the top of the menu. That will give you the “Edit Fixed Object” window as shown. Enter, “Origin,” as the Common Name, which is what will show on the map display. Set the Technical Name to, “(0,0,0).” Use the pull downs to set the Style and Class to, “F Star,” and, “Star.” Finally, leave the Coords, X, Y and Z as 0, 0 and 0. Hit OK. That gives you the “Origin” point for the Compass Rose.

Similarly, make a point, “+X,” at X:9, Y:0 and Z:0(9,0,0), “+Y,” at (0,9,0), and, “+Z,” at (0,0,9). Set the Style and Class of these to, “G Star,” and, “Star.” The resulting map should look a bit like this.

Our 3d compass rose in ChView’s default view orientation.

So what can we see here? First of all, we can see that ChView has a rather odd orientation by default. I’m not quite sure what that’s all about, but I’ve seen a lot of weird axis definitions in computer stuff. We can fix that readily enough, but first I would like to introduce the various buttons, sliders and other tools that ChView 2 places readily to hand.

First of all, let’s look at the rotation controls. These are the three sliders in the first bar beneath the menu bar. As shown in the image to the left these bars control, from left to right, rotation around the Z-axis, the X-axis and the Y-axis. My own copy of the program includes a, “zero,” button for each axis to return the rotation to default value. Until and unless I can get permission from ChView 2′s creator to put up my own version that won’t be available generally. If I do get permission to put up my own mod of the program, I’ll likely replace that with a numerical input field, instead, so ignore that part anyway… Play with the sliders to get a feel for them. If you have the compass rose entered, that can be a guide to help you orientate.

The next element we’ll look at is the toolbar below the rotation controls. These tools vary considerably in their usefulness. I don’t generally use the time controls for much, so I’m going to kind of gloss over those for the moment. Suffice to say they operate similarly to the VCR/DVD controls they somewhat resemble and they’re pretty readily understandable with a bit of playing around. The scale controls, which I neglected to label, lie between the printer icon and the grid display toggle. These are also fairly easily understood with a little playing around. The printer icon is actually useless. Print facilities have not yet been implemented in this program.

A quick digression into terminology. In ChView-speak, routes are special objects intentionally placed between fixed objects on the map. They represent geographic relationships between the connected objects, for example, as the name implies, routes between those objects. Links are automatically-generated lines between objects, that give a sense of the distance between the objects. Links can, in fact, be labelled with the distance represented. In any case, links will be colored differently based on the categorical distance represented. Lets open the Preferences panel and look at the Links tab.

The settings here are a little different from my previous compass rose image. I’ve decided to show numbers on the links. This isn’t actually all that useful on a compass rose, but it can be of great utility for close-in work with starmaps. Once you get far enough out, the numbers(which describe the distance represented by the link) can muddy up the map to the point of incomprehensibility. The top input field allows the user to set the shortest link length that is desired to be shown. The top line style will be shown for all links with a length between that minimum and the value entered in the next field, and the next style will be used for links of length between that value and the one entered in the next field and so on… The field at the very bottom represents the very longest link that will be shown. A very long maximum length will result in a very busy map that could take a very long time to redraw if there are a lot of bodies. That last value also sets the maximum individual step allowed when using the route finder(Main Menu Bar>Report>Route Finder). The route finder is of great utility in figuring out distance-limited routes between objects on

A picture of the final compass rose in a good orientation. Also shown are the tear-off toolbars.

the map. The route selected isn’t always the minimum path between two objects, but the deviation from the minimum path is usually pretty obvious.

After unchecking, “Show Numbers,” again, this next image shows what the properly rotated compass rose looks like. This also shows the tear-off toolbars in action. I’m not sure how useful this feature really is, but hey. You can redock the bars as you wish or simply click the dispel button and they will return to their previously docked location.

As you can see from this image with the compass rose, an orientation with the z- and x-

axis rotations zeroed and the y-axis rotation screwed to the left or right edge of the bar, will resemble the common 3d page map structure of y as vertical, x as horizontal and z as out of the page. One could even imitate the style of map used in GURPS or Space Opera space atlases by adding a z-axis value to the common name of each Fixed Object. That would be no end of cool.

When creating new stars(Fixed Objects), if nothing is currently selected, the default

A test sector in the GURPS Space or Space Opera atlas style.

position of the new object will be (0,0,0), if one object is selected, the position will be the same as the selected object, and if more than one body is selected, the default position of the new object will be equidistant between the selected objects. You select multiple objects by holding down {shift} while left-clicking the objects. Try creating a few bodies. I would expect your map to look nothing like mine to the right. Have fun with it…

When you try to save this, you’ll run into a couple of problems. The first glitch is that the Save dialog is exactly the same as the Open dialog with no field to enter a name. You’ll also notice that there’s no obvious hint as to what the naming format is that it filters on. The second problem can be fixed with a quick look at the source code which is conveniently zipped into the jar-file. The format is “{name}.chv.xml”. The second problem is a real bug and it needs fixing. In the meantime simply use a text app like TextEdit or Notepad to create a file in the desired location, “{name}.chv.xml”. When in the broken Save dialog, you can simply click on the file you just created and ChView 2 will put the data into that file. The actual save routine is fine, it’s just the interface that’s bollux.

I forgot to mention another way to rotate the map. If you hold down the right mouse button and drag you can rotate the view about the z- and x-axes. Also, I forgot to put up a real pretty view with the grid toggled on. I rotated the view somewhat arbitrarily and hid the link lengths in order to minimize conflicts. The view is a bit odd, but it shows clearly the way the grid works. I selected all of the objects in the map and centered the view, thus the plane is a little bit below the z-zero point as the objects I placed are weighted somewhat towards the negative-z. I kind of wish, when doing this sort of thing, that ChView had a compass rose faculty.

Next time I’ll get into importing real-world data from existing catalogues, and using Chview 2′s tools to help with detailing your little patch of the universe.

I’ll leave you with some interesting links that might give an idea of where I intend to go with all of this.

Solar System Live by John Walker

3-D Starmaps by Winchell Chung

GURPS Traveller: First In Designer’s Notes(an inspiring Pyramid sample article) by Jon F. Zeigler

 3D: Mapping the Solid Subsector(inspiring JTAS article[not free]) by Christopher Thrash

Internet Stellar Database by Roger M. Wilcox

The Division of Territory in Society by Ed Stephan

Medieval Economics by Philip McGregor

GURPS Architecture by Matt Riggsby

The Theory of Interstellar Trade by Paul Krugman

Low-Tech Economies by Matt Riggsby

Adventure Cargo and Interstellar War by S. John Ross was apparently useful to the designers of GT: Far Trader (GURPS Traveller).

Thank you for your attention. I hope this was as helpful to you as it was enjoyable to me.

The Astrographer

More Work With Planet

Last week I started working with Torben Mogensen’s planet heightfield generator. This week I’m going to continue on that vein a little longer.

First off, we’ll start with a method to create a seamap image for our new world. Let’s start by creating a new color file.
0 0 0 0
1 255 255 255
2 255 255 255
3 0 0 0
4 0 0 0
5 255 0 0
6 255 255 255
7 255 255 255
8 0 0 0
9 0 0 0

Copy and paste the code snippet above into a flat text file named sealand.col.

Here I’m going to make a short digression into what all of this opaque text means. Each column consists of a color number and three numbers representing, in order the red, green and blue values referenced by the color number. The color numbers range from 0 to 65535 and the rgb values having different ranges depending on the output image type. If the output image is 8-bit as is required for BMP output, then the range of values for the red, green and blue channels is 0 to 255. If the  output image is is 16-bit, which, as far as I can tell, can only be handled by the XPM file format(-x option), then the red, green and blue channels can range from 0 to 65535.

In retrospect I notice that Mr. van Vliet’s 16bit.col file has color numbers and values that extend up to 65536. This doesn’t seem to break the program, but I don’t know if it effects the output. According to Mr. Mogensen, the break between sea and land occurs at a color number of ({maximum color number} + 6)/2.

The rows, therefore, each represent a numbered color value. The first row is usually set to black(all channels zero), the second to white(all channels set to the maximum value for the format). The third row, numbered 2 is the chosen background color. The fourth row, numbered 3, is the color desired for graticule lines. The fifth row, color number 4, is the chosen color for continental outlines, and the sixth row, numbered 5, represents the color for other contour lines.

The seventh row and after, numbered 6 through the highest color number, represent increasing altitudes. Color values are interpolated for color numbers between entries.

In the case of the sealand.col file, ocean areas are represented in white and land areas are represented in black. This could readily be inverted by setting colors 6 and 7 to (0,0,0) and 8 and 9 to (255,255,255) if necessary. Easy-peasy.

Currently I’m trying to figure out how to adapt the Default.col, Burrows.col and Olsson.col to Wilbur. I think the Mars.col might be worth adapting as well.

One problem with random generation of planetary terrain is the lack of control over the hydrosphere fraction. John Olsson’s is capable of approximate hydrosphere control(it’s done using the histogram of a not necessarily equal-area projection, so it’s not terribly accurate). There’s a couple of tricks with planet.

The first one is simply to generate the 16-bit heightfield as per the previous post. Then you can project that to an equal-area map using Flexify, Matthew’s Map Projection Software, Flex Projector or G.Projector. Then you can just adjust the sea level, in Wilbur perhaps, checking the histogram as you go till it approximates your desired level closely enough. This one works well for me because I’ll likely be changing things a bit anyway.

Another method that I used at one time is to try generating a number of maps in Peters projection(a case of the cylindrical equal-area projection). Planet returns the ocean cover fraction to stderr which should show up on the console. Then I save the map image along with a text file describing the parameters and ocean fraction(in other words, the hydrosphere) in a library folder. In my case I subdivided my “Planets” into a set of lesser folders by approximate hydrosphere. For example, “Planets/1,” “Planets/2,” …, “Planets/9,” “Planets/0,” with the, “1,” folder holding maps with a hydrosphere between 0 and 10%, “2,” folder being >10 to 20%, and so forth, with the, “9,” folder holding maps with hydrospheres from >80 to 90% and the, “0,” folder representing >90 to 100%. Usually ten percentage points was close enough for the kind of work I was doing and I could just set my planet’s hydrosphere value based on the value for my map. When I was just trying out settings at random, it seemed like a shame to throw away all those perfectly good maps.

Just wanted to get this out there. Now onto other things…

The Astrographer.

Using “Planet” for 16-bit planetary maps

The map on this page got me to thinking about automated terrain generation again. I’ve discussed the inadequacies of most terrain generation before, and I stand by it. On the other hand, as Realmwright says, there are advantages to exploring and filling in an existing map. Much as die rolls serve to spur the imagination in the generation of other planetary parameters, so does a randomly genned map. That’s not to say I’d use a generated map exactly as is. As a geography guy I feel it’s a matter of honor to improve the terrains and maps I’m presented with.

I had originally thought that the map on Realmwright’s page was generated using Torben Mogensen’s Planet generator, but it turns out that the Donjon generator he links to is actually a working implementation of John Olsson’s(johol) old FWMG generator. The cgi on Mr. Olsson’s online app no longer works properly, but he has some good stuff on how it works as does Mr. Mogensen(under Great-circle Faulting). While I was looking around I got to playing with Planet and other random generators and thought it was time to go over that aspect of worldbuilding. That, and I haven’t had a good post focussed on mapping in awhile, and I enjoy doing those…

Awhile back I generated an entire library of planetary surfaces using planet. I saved the settings(seed[-s], initial altitude[-i], distance variation[-V] and altitude variation[-v]) that control the shape along with small-ish thumbnails(2000×1000) in latlong and Peters projections. I have no particular affection(or disaffection) for Peters projection, but it provides a decent approximation of the resulting world’s hydrospheric fraction. Based on the given hydrospheric fraction, I stored the images and their settings files in one of ten sub-folders(named: “0″ for 0-9.9…% ocean, “1″ for 10-19.9…% ocean and so forth). Random generators, being random and all, aren’t the best thing for providing just the world you want, but it helps if you can shop around a bit…

I’ve been off the Sadwillow project for awhile now, and I’ve since adapted the existing map to use in a competition as Kazh, the homeworld of the Klarr. Well, I needed to alter it a bit for the UNSEA universe anyway. Since the latest version of planet uses a slightly modified algorithm that doesn’t produce exactly the same results from a given input, I decided to feed the settings for the old Sadwillow into planet and see what came out.

Not exactly what I was looking for. A bit drier than I was hoping. Still I kind of like the shapes. Could I somehow invert this…

An interesting enough map. A whole lot of dry land. With Sadwillow I was definitely looking for something moist and pleasant with smallish land masses. This looks dry and marginal with large deserts. Just the opposite of what I was looking for. Hmmm… It occurred to me that I could invert a heightfield of this in Photoshop or Wilbur, but I decided to do an experiment.

The original Sadwillow(now Kazh) and this dry little world were generated with a seed of -s 0.26544111354, an initial altitude of -i 0.0227, a distance contribution to variation of -V 0.024 and an altitude contribution to variation of -v 0.386. It also had an offset in longitude of -l 120.0, but we’ll just leave that alone for now, that’s just an adjustment to make the map all pretty-like, I won’t know how to optimize that till I see the final terrain. By inverting the initial altitude, distance variation and altitude variation(-i -0.0227 -V -0.024 -v -0.386), I hoped to create an inverted heightfield. I didn’t know enough to be sure, but experimentation is cheap in this case, so I banged out another test image.

That looks better. A little flat, but random gen never puts the mountains in the right place anyway…

Well! How about that? It looks like my conjecture paid off. So now I have a pretty picture with a bit of hillshade effect. What can I do with this? One thing I did was take it into Photoshop and use the Flaming Pear Flexify 2 filter to convert my image into a cylindrical equal-area projection. Then I used the magic wand to select the ocean areas and the histogram to see what fraction of the total surface are was represented by hydrosphere. It came to about 72.0% hydrosphere. That’ll do. Incidentally, if Sadwillow was the same size as the Earth, with a total surface area of about 510 million square kilometers, the kiwi-shaped continent would have a surface area of about 77 million square kilometers, the continental mass in the northeast(overlapping into the northwest) would have an area of about 38 million square kilometers and the island and little continent that are to the east of the kiwi kissing it on the beak have a total area of about 18 million square kilometers. This would be comparable to the continental cluster of Africa and Eurasia(about 79 million square kilometers), Africa and Australia(38 million square kilometers) and South America(17.8 million square kilometers) respectively. I’m thinking Sadwillow will be a little smaller than Earth, but I still think those landmasses are quite large enough for my purposes. In fact, the Kiwi seems a bit big(let’s just call it that. You know the settlers will.)

Now that we have a satisfactory terrain, how do we earn the name for this post(you know? The whole 16-bit thing?) I found a thread in the shatters.net forums by John van Vliet on this very topic.

Just copy and paste the contents of his 16bit.col file or the code block I have listed below into a text file and save it as… wait for it,”16bit.col”

0 0 0 0
1 65536 65536 65536
2 0 0 0
3 0 0 0
4 0 0 0
5 0 0 0
6 0 0 0
4096 4096 4096 4096
8192 8192 8192 8192
12288 12288 12288 12288
16384 16384 16384 16384
20480 20480 20480 20480
24576 24576 24576 24576
28672 28672 28672 28672
32768 32768 32768 32768
36864 36864 36864 36864
40960 40960 40960 40960
45056 45056 45056 45056
49152 49152 49152 49152
53248 53248 53248 53248
57344 57344 57344 57344
61440 61440 61440 61440
65536 65536 65536 65536
Once you have that saved in the same folder as you have planet, then you start up a terminal(this is all CLI), set your working directory to the folder with planet, and enter the following:
./planet -C 16bit.col -x -s 0.26544111354 -pq -w 2000 -h 1000 -o sadwillow2.xpm -i -0.0227 -V -0.024 -v -0.386 -l 120.0

Your mileage may vary, but I don’t have any image editors on my computer that handle xpm. At least not in 16-bit. That’s okay. If you don’t have Image Magick on your computer, I’d strongly suggest you go and grab a copy. I’ll wait for you…

That wasn’t so hard. MacPorts even has an easy option to compile it in 32-bit. No muss, no fuss. On a Macintosh, of course. They have direct downloads of 8- and 16-bit versions for Windows and various Unices, so that much shouldn’t be too hard. For this purpose, the Q16 build will be both necessary and sufficient. Q32 should work, but won’t be necessary.

Once you have IM installed nicely, try the following code:
convert sadwillow2.xpm sadwillow2.png

The result should be a nice 16-bit greyscale png suitable for opening in any version of Photoshop later than version, I think, 5.

This is a fairly low quality, 8-bit JPEG of the heightfield, ’cause WordPress doesn’t handle 16-bit PNGs all that gracefully. It’s also kind of small, but it’s just to demonstrate.

There you are. You are now the proud owner of a 16-bit heightfield produced by tetrahdral subdivision as implemented in Torben Mogensen’s world-famous, fancy-dandy planet generator.

Now all I need to do is boot up my Windows partition, open this in Wilbur and port it to hf2 or bt format.

I could do the same conversion here on my mac with GDAL…
gdal_translate -ot Float32 -of BT sadwillow2.png sadwillow2.bt
, but since I expect to be hand-modifying significant parts of this heightfield, Wilbur would probably be the way to go. Also setting the geographic extents in Wilbur is pretty easy and kinda miserable in GDAL. YMMV.

Enjoy. I’d love to see any cool worlds you create with the help of this. Just drop a line…

The Astrographer

UNSEA

A rather blatantly Star Trek inspired ship. Presumably from the early- or mid-22nd century. I got the broad shape I wanted, but I’m not too happy with the details. I like the lettering, though. All it needs now is a UNSEA meatball. And a better spaceship…

This is a post introducing the new world where I am setting my science fiction work at present. I’ve named it for a major organization in-world, the United Nations Space Exploration Authority.

I like the idea of a point of departure a little closer to the present than is usual for starfaring science fiction, so I’m going to assume that a sublight version of the warp drive is introduced sometime in the 2020s. Maybe the White-Juday interferometer experiment will prove surprisingly successful leading rapidly to breakthroughs. By the mid-2020s small warp drives are commonly used to cheaply shift mass into Earth orbit via Jerry Oltion’s tangent vector translation maneuver(TVTM or TVT maneuver) I mentioned in an earlier post.

2012 in review

The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.

Here’s an excerpt:

600 people reached the top of Mt. Everest in 2012. This blog got about 6,300 views in 2012. If every person who reached the top of Mt. Everest viewed this blog, it would have taken 11 years to get that many views.

Click here to see the complete report.