GeoTiff Aerial/Satellite Photo Source?

[nudata 10]

From a quick look at the SDK it seems that GeoTiff is the preferred format for aerial/satellite photo-scenery. I would like to import a GeoTiff photographed area to "play with" so I can get the resample/INF process understood. Any area other than the SDK samples would be ok. Does anyone know of a source of a GeoTiff photo(s)? I have done the Google search and keep running into $$$ for downloads or CDs. Dick near 5G8

[rhumbaflappy 113]

Hi Dick.Of course, what we need for all the FS series are images that are in wgs84 datum, and lat-long projection ( geographic ).Those images can be of any type, but to convert them to geotiff is a 2-part process. First, make a tiff image. This can be done with MSPaint, PaintShopPro, Photoshop, and other programs. As long as you can load the image, you can save it as a TIFF type.Second, use GeoTiffExamine to "tag" the tiff, and make it a geotiff:http://www.mentorsoftwareinc.com/freebie/free0699.htmDick

[nudata 10]

Thanks for the fast reply and info. Looks like the program I need. However, I am stuck on trying to determine the "pixel scale" value. First I assume that scale equals size?? Second, I have corner lat/lon extents - NW & SE. The answer may be obvious but how do I determine the "pixel scale" from that info? I have paint Shop Pro but although there is a page under Image Info that has a line for pixel width/height, there are no values shown.Thanks, Dick Boley near 5G8>Hi Dick.>>Of course, what we need for all the FS series are images that>are in wgs84 datum, and lat-long projection ( geographic ).>>Those images can be of any type, but to convert them to>geotiff is a 2-part process. >First, make a tiff image. This can be done with MSPaint,>PaintShopPro, Photoshop, and other programs. As long as you>can load the image, you can save it as a TIFF type.>>>Second, use GeoTiffExamine to "tag" the tiff, and make it a>geotiff:>>http://www.mentorsoftwareinc.com/freebie/free0699.htm>>Dick

[rhumbaflappy 113]

Hi Dick.Pixel span should be the same as the old resample.X Pixel Scale = ( maxlong - minlong ) / ( PixelsWide - 1 )Y Pixel Scale = ( maxlat - minlat ) / ( PixelsTall - 1 )Sometimes an image will have a metadata file with it that will tell you the spans ( Scale ). Leave the tiepoint pixels at 0, as that is the NW corner of the image. Tiepoint world is the NW longitude (X) and latitude (Y).Dick

[nudata 10]

Thanks - I was shielded from the old re-sample INF by GUIs. Now I am too impatient to await someone writing one for FSX. For low and slow it will be photo stuff. Just have to control myself due to the much larger file sizes. My PC will tend to lbe a imit in that direction. In my case the 60cm millenium sample texture simply does not resolve fast enough thus negating its visual advantage until the airplane is past it. Probably best left for airports where there is extra time for the hardware developing the resolution display during a nice slow approach.Saving my pennies for an all new motherboard, CPU, and a PCIe video card. Maybe the Easter Bunny will be generous!Thanks again,Dick Boley near 5G8

[rhumbaflappy 113]

Hi Dick.Probably the best advantage of the new resample is for 1 meter/pixel data. Look up NAIP images on the internet. Many states have them, some already in lat-long geotiffs... so you would just have to declare the destination bounds in the INF. They are 1 meter color images.Some are in UTM projection, so they'll need reprojection. They are usually arranged by counties.I made one for my small town of Delavan, Wisconsin. Here is my INF:{Source}Type = GeoTIFFSourceDir = "."SourceFile = "Delavan_NAIP_2005_b.tif"Layer = ImageryVariation = DayNullValue = 255,255,255{Destination}DestDir = "."DestBaseFileName = "Delavan_NAIP_2005_c"DestFileType = BGLCompressionQuality = 85LOD = 7,17CompressionQuality = 85 made a BIG difference in file size, but didn't hurt the quality much ( 51mb vs. 181mb ). It was just one season.Dick

[Guest jimjones]

Thanks for that CompressionQuality info. Works great on night scenery where detail is less important and gets a much smaller file size, about half.Jim

[nudata 10]

I concede--- I simply cannot get a GeoTiff through Resample. Of course the Millenium Microsoft files work great.I suspect the lat/lon info but I have little experience with this cartographic world. From what I have seen the NAIP stuff seems to be GeoCoded lat/Lon. I would guess that Resample wants its normal expression in degrees, minutes, seconds or the decimal equivalent. Do not know how to convert. So, just to be clever I stuck some lat/lon in the conventional format into the GeoTiff Using the GeoTiff Examine program.http://forums.avsim.net/user_files/160626.jpgSubsequent reloads confirm that the values were in the GeoTiff.However, dropping the INF (below)results in an immediate flash of the CMD screen with no results.http://forums.avsim.net/user_files/160627.jpgTried several other programs for viewing the GeoTiff file and it seems that the lat/lon really is not being placed in a manner that equals the Microsoft GeoTiff files. Without going into the gory details of all that I did, from this description - any hints?Dick Boley near 5G8

[nudata 10]

From all of my fiddling around it seems that Resample must require a Tag that says WSG84 for the datum. I found an elevation picture with wgs84 and it sampled ok. I was hoping to just use any old inputs to make sure I was following a basic set of steps. From looking about in the NAIS photos they appear to use NAD83 instead of WGS84. The problem is, how do you convert NAD83 to WGS84? Global Mapper has a facility but it also has a $280 price tag! "Googeling/searching" leads me to dead-ends for a conversion program which is probably my missing link unless there is a nice source for free photos in GeoTiff format or a free datum converter. In the mean-time I will play with the manual calculation for Pixel Scale using conventional BMPs/TIFFS with corner extents.Dick Boley

[rhumbaflappy 113]

Hi Dick.I think most NAIP images are UTM projection, and we need Geographic ( lat-long ) WGS84 is actually the Datum.I think you can still get a free ERDAS viewfinder:ftp://ftp.gi.leica-geosystems.com/softwar...VF_Setup_21.EXEAnd it allows you to save the image in a reprojected format.Dick

[nudata 10]

Yes, the Viewfinder program remains available (V2.1). However, I cannot make it open a file of any kind. It always goes to the error shown below. Clicking OK takes me to an error that says that they do not support "LZW compression" after that the program fails.I have tried various compatibility modes since it was first written in 1998 with the most recent updates in 2002. There is no apparent support for the program on the company web site. However, reading the program's diecription it does seem to be what I need. Any hints on this?Thanks,Dick Boley>Hi Dick.>>I think most NAIP images are UTM projection, and we need>Geographic ( lat-long ) WGS84 is actually the Datum.>>I think you can still get a free ERDAS viewfinder:>>ftp://ftp.gi.leica-geosystems.com/softwar...VF_Setup_21.EXE>>And it allows you to save the image in a reprojected format.>>Dickhttp://forums.avsim.net/user_files/160859.jpg

[scott967 62]

I use an image program called pmview pro:http://www.pmview.com/which can change many of the tiff options, such as Intel/Motorola byte order, White is 0/ Black is 0, and compression.There are freeware programs, GIMP, Irfanview, XnView which can set the compression for tiffs.scott s..

[nudata 10]

The program DGWarp was referenced back in 1994 on Avsim. It looks like it will do reprojections to get from NAD83 to WGS84. The program is based upon a suite of functions called GDALWARP.Learning the arcane terms of cartography just to be able to take a photo from the Web to FSX takes a lot of time. http://www.forestpal.com/image_reprojection.htmlDick near 5G8

[scott967 62]

To get the geo tags into a tiff, first create the tiff in geo/wgs84 (try using google earth for starters just to get the hang of it).You can get the following utility:ftp://ftp.remotesensing.org/geotiff/libge...listgeo_GUI.zipand install it. It will put in some DOS utilities and a windows GUI frontend. Using the ListGeoG tool, find the millenniumimage3.tif in the sdk sourcefiles, and then click on "list". It will copy out all the tags to a file millenniumimage3.gtf. then you can use the copy function with this file, your souce tiff, and a destination tiff file. This will insert all the geotiff tage from the sdk tiff file into your tiff. Of course, the tiepoint and scale will be off. But now you can use the geotiff header examiner to move the correct values from a tfw file that was explained earlier into your tif.But it's probably easier just to build the inf file if you don't have geotiff to begin with.scott s..

[nudata 10]

Scott,I found that suite also. Just began to try it when I ran into a disk slowdown. 2 days later I fixed that - disk errors and locked in PIO transfer mode. I have no idea how the average person could ever deal with such a nasty OS as XP. It works, but troubleshooting takes someone who does it for a living!So, after I clean up some stuff remaining from my panic I will get back to "tiffing". I hope some nice programmer soon automates this process to handle the many source formats!Dick near 5G8