Satellite scenery

[Guest jcisneros]

Hi! I want to share with all you my work with the MS Terrain SDK and landsat 2000 satellite images.The colors of the images have been modified in order to achieve the most realistic color, job in what I

[arno 1]

Humm, I think it is not really possible to tell resample to use a lower resolution. The only thing you could do is to resize the textures, after they have been created, to 128x128 (which means 9.6 meter per pixel). This should make the size 4 times smaller.

[Guest jcisneros]

Thanks, but I think that maybe it crashes when the bgl file is expecting to load a 256 by 256 bitmap and found a 128 x 128 one. But I'll try to work with this idea and I will tell you my results.J Cisneros

[arno 1]

I don't expect it will give a crash. I think the scenery engine will notice that a mip is missing and then just display the highest mip available.

[LuisFelizTirado 33]

Hola Juan?,This is an extremely interesting situation and one that we have faced many times in the past. Custom ground textures take up a lot of space, and, if you add seasonal and night textures, then you can multiply by 6 the number of textures that you will have.But, I am curious about your comments as to the source material and its resolution. If your Landsat images have a resolution of 14.5 meters per pixel, then from what I understand, you do not have 9 times greater resolution than you need. This is easy to demonstrate: simply look at your results.You would need source resolution of about 0.53 meters per pixel in order to have the 9 times greater resolution.Here are some examples where you can see the difference. This is an image with a resolution of about 0.4 meters per pixel:http://forums.avsim.net/user_files/100006.jpgAs you can see, there is much detail. When I resize it to 1/10th of that (which gives me a resolution of about 4 meters per pixel), this is what I get:http://forums.avsim.net/user_files/100007.jpgThis resolution is very close to the final 4.77 meters per pixel (approximately) that Resample will give for the final custom textures. You can easily see that there is much more detail than in your low resolution Landsat images.But, all this is not very useful. Resample will always resize and resample all your source images to the final resolution of 4.77 meters per pixel. So, you will never have too many ground textures. Or, at least this is how I have understood the matter.By the way, if you are creating custom textures for the Guadalajara area, you should be able to find good-quality color aerial images very easily. Most of the inhabited world (and much of the uninhabited world) has been photographed from the air and these images can be obtained with just a little bit of ingenuity. For your area, you should try the military cartographic institute, or, if you prefer them for free, just ask around. The above images were given to me by my cousin, an architect, who had a complete set covering the urban area and more. You should be able to get the same thing through relations, friends, etc. These types of images will give you much better results for your custom textures than Landsat images.I hope that I have not misunderstood your comments.Best regards.Luis

[LuisFelizTirado 33]

By the way, Juan, I meant to say, congratulations on your scenery. It is not easy at all to color those Landsat images, and you have had great success. It looks very realistic.Best regards.Luis

[Guest jcisneros]

Thanks Luis:Despite the lack of autogen, with the trees and the houses (the default in FS never seen in my country), I have enjoyed flying these sceneries, seeing thought the windshield those images matching so well with the real world By the way, I have rendered about 60 square degrees of central M

[arno 1]

Hi Luis,About the 9 times, that is correct. He writes he has 9 times more diskspace, which is correct. The resolution is about 3 times too high (circa 5 vs 15), which results in 3x3 more data.I am curious if the use of 128x128 bitmaps works with the photos scenery, that could reduce the amount of data by 1/4 again, might be useful when your source data has a lower resolution then resample required.

[LuisFelizTirado 33]

Thanks for the comments, Arno. I was confused before, and to tell you the truth, I still am, so would welcome clarifications.The Landsat image does not have 3 times higher resolution than the final custom textures. It has, on the contrary, only about 1/3 the resolution, considerably lower.That Landsat image therefore is smaller than a comparable image with 4.77 meters per pixel resolution, and only takes up a fraction of the hard disk space of such an image.Resample must enlarge this low-resolution satellite image in order to get the required resolution, so that in the end, the custom textures take up more hard disk space than the Landsat image. Of course, the conversion to the compressed DXT format must be taken into account in all this. But, this is not 9 times more textures than could be had otherwise.No matter the resolution of the source image, the final custom textures will always have the same size and take up the same hard disk space. Because they will always be at 4.77 meters per pixel. There is no way to change this.Or, at least, this is how I understood the matter. If I am mistaken or not understanding some key factor, I would be grateful for explanations.Perhaps what is meant is that Juan would like a way to obtain custom textures that do not take up more disk space than the original low-resolution image. Not that he has 9 times more disk space, but that he has less disk space, because the custom textures take up more of it.By the way, Juan, I have created custom autogen texture sheets for my flights here. They represent the buildings and trees that we have and make Flight Simulator give a very different experience. You may want to consider this option, although the problem in your case is placing the autogen over such a large area.Best regards.Luis

[Guest vlada stoje]

Hi Arno,I suppose normally with the terrain texture size slider set to High, the FS needs the 256 mip in the closest view, else with the reduced textures (the top mip 128) it will show black squares or some generic lc textures. There is the possibility to set that slider to Medium, then the reduced textures (10 kB one DXT1 tile) can be visible also from close view, but I think this Landsat scenery is best for flying in the extreme altitudes with some spy plane or even orbiter!Cheers Vlada

[arno 1]

Hi Vlada,I never tested it, that is why I would find it interesting to know. Does the scenery engine show nothing when it can not find the required mip or does it just use a lower quality mip? I expect the last, but I am not sure. This is also how it works for other scenery elements.I agree that scenery based on such low resolution photos is mainly useful when flying at high altitudes. The current 4.8 meter resolution is only just enough for VFR flying.

[Guest vlada stoje]

Hi Arno,I also didn

[Guest jcisneros]

Thanks for your comments Luis:That

[LuisFelizTirado 33]

Hola Juan,I guess that I just misunderstood before - perhaps it is a simple language problem. Thanks for your patience.I have not tried removing the custom texture and just leaving the mipmaps, and wonder how this could be done? Ground textures are 256 x 256 pixels, and if you substitute something that is 1/4th the size (128 x 128 pixels), FS will probably display a gray tile or, if you are lucky, the underlying default land classification, as Vlada says. But, I have not tried this since the results would not be desirable.Consider that using a 128 x 128 pixel version of your ground tile will give you something that takes up 1/4th the space, but if FS displays it (and it probably cannot), then the ground tile must still be enlarged (in real time? by the scenery engine or the graphics card?) to 256 x 256 pixels to cover the LOD13 quadrant. The loss of quality would be immense, and this with textures that are already of low resolution because of the source. You would probably not be happy at all with this solution.If it is of any consolation to you, your custom textures are not taking up 9 times more disk space than your original source image. While the resampled and sliced image is effectively 9 times larger, you then compress these ground tiles to DXT format. This reduces the size for each tile from 176 kB to 43 kB, exactly 1/4th the size. So, your ground tiles only occupy 2.25 times as much disk space as your satellite image.This is the price to pay for flying over something that looks exactly like the real thing. Best to just enjoy your flights and not worry too much about it all.By the way, since you mention that you will be resampling your project all over again, you might want to consider resizing the source BEFORE letting Resample create the tiles and the bgl. Resample uses a rather simple filter and you might get slightly better results if your image editing program has better filters. Or, you could use Image Tool by Elrond Elvish (yes, that is the name that he uses!) - this can be found in the AvSim library and was made specifically for this purpose. It provides a variety of high-quality resampling filters and is very easy to use.Best regards.Luis