Finally - a free reprojection utility for background im...

[Holger 0]

Hi Bob,that's an easy one - you have to change the units ("Change Output Pixel Size") to degrees.About the color to greyscale thing: I haven't worked with an RGB image yet but there's that "Band" box in the top line of your first screenshot. It's possible that you have to repeat the process for all three "bands" (R, G, :( by selecting a different one for each save.Hope that helps.Cheers, Holger

[bob.bernstein 0]

Sounds logical, hadn't thought that through...since the imagry I think of as being sized to 4.75m/pixel...I was thinking that meters were still the appropriate unit. Logical, though...as the units of th inf file is degrees/pixel. Thanks for the help, H. I've been fooling around with the bands myself....more experiments required. best,B

[bob.bernstein 0]

My solution of saving the reprojected geotiff as a color image was to open it in mapmaker gratis, and then use the bitmap utility format converter to save as a bitmap.B

[Gridley 257]

Can anyone point me to a download for the ECW utilities, the ERMapper site appears dead for me since early this week...Thanks!sg

[Holger 0]

Howdy,the Netscape/IE plugins are available here: http://www.resmap.com/ecwplugins/download.htmand the ERMapper ECW site is here: http://www.ermapper.com/downloads/ (just tried it, it works for me; if it doesn't for you try cleaning your browser's cache).Cheers, Holger

[Gridley 257]

Thanks, Holger. I can't get that second one to load- must be that "large scale internet attack" is read about on CNN...;)You know, I had a similar problem a few weeks ago - I was the only person I know of that couldn't get to hifisim.com...strange.Thanks again!sg

[Holger 0]

Hi Scott,I had similar problems with the MicroDEM site a while ago. In my case the solution was to click on the ISN provided in the error message (took me only two weeks to figure that out, duh!). Another option is that your browser's security settings are too high.Cheers, Holger

[Gridley 257]

Thanks for trying Holger - neither of those worked for me (browser settings are already lower than I'd like) - could be a firewall issue, but it'll be a week before I get a response from my tech support gang, and then it'll miraculously start working again...I had a friend download them and upload them to my FTP - I'm back in business!Best,sg

[Guest]

Howdy Everyone,I need some help and direction in using ViewFinder etc. Here are Holger's instructions for downloading and processing a satellite image:1. Go to http://glcf.umiacs.umd.edu/index.shtml , then "Download Data", then "Map Search", then check the "ETM+" box, then select the Lat/Long tab. Enter the bounding coordinates of your area and click on "Update map". "Preview and Download" will bring up all available image sets and you can check the previews to pick one or more. Make sure that the image Attributes are "Ortho, GeoCover" and the Type "GeoTiff". Click on download. The individual bands are named *nn*0.tif.gz - e.g., Band 1 is *nn10.tif.gz. Usable for scenery work are Bands 1-5, 7, and 8. The choice is yours. More information about the content of the bands is available here: http://rst.gsfc.nasa.gov/Sect1/Sect1_3.html2. Once you have one or more bands and/or images downloaded, unzip them and load and save/reproject each one with ERDAS ViewFinder.3. Use your image processing software (Photoshop, PSP, Gimp, etc.) to crop each band to the same size and combine them as color RGB, if desired. Important: write down the start and end column and row of the area you're subsetting. Then save the subset as bmp. Note that your area should not be bigger than approx. 4000x4000 (double that for Band8, if saved as 8-bit greyscale), otherwise Ground2K4 will have difficulties handling the large file size.4. Calculate the upper left and lower right corner coordinates for calibrating the image in Ground2K4. Open the ViewFinder .tfw file of your reprojected image in Wordpad or Notepad and use the X/Y resolution (the first line) and longitude and latitude (the two bottom lines) of the original image to calculate the subset image's corner coordinates as follows:N(subset) = N(original) - (Yres * Nrow)W(subset) = W(original) + (Xres * Wcolumn)S(subset) = N(original) - (Yres * Srow)E(subset) = W(original) + (Xres * Ecolumn)(use negative lat/long values for western longitudes and southern latitudes)5. Start Ground2K4 and initiate your new project.I'm having problems trying to get a decent satellite image and manipulating an image. I have no problems downloading from http://glcf.umiacs.umd.edu/index.shtml but run into difficulties from there on working with ViewFinder. First I unzip an image file to an empty directory. Then I open the TIF file in ViewFinder with the only option available being a grayscale image in the window. I save a copy of this image elsewhere for later use in Ground2K4. Once the image is opened (a nearly equal-sided parallelogram) I open this image and set the options to DEGREES, Geographic, etc. and save it again. This comes out as a stretched parallelogram but I can then read the corner coordinates to apply to the original image for Ground2K4. This seems like going way out around the barn to get where I want to go but I don't understand Holger's instructions for calculating the coordinates (#4 above). Here's what my TFW files look like:0.0001284410000000000000.00.0-0.000128441000000000000-110.5607084150298845.617072828223918Something appears missing or ???? in my TFW file. Either that or I just don't understand what Holger is saying and probably am doing something wrong somewhere along the line.I like to use band 8 black and white images but they are very large files and continually cause Ground2K4 to give an error message, it not being able to redraw the image after moving around a bit in it. I'd like to use just a part of an image but can't figure out how to "cut out" a portion and determine its corner coordinates.When I open an image in Ground2K4, the grid appears as rectangles rather than squares as in the images that Holger posted. Is the image still useable in Ground2K4?I also don't understand instruction #3 above. I downloaded Gimp but can't grasp the combining bands procedure to get a color RGB. An area should be no bigger than 4000x4000 whats (pixels, meters, miles, acres, hectares or what?)? How and where do I find these numbers? It's probably right there in front of me but I can't recognize it or them.I guess I came along too late in the game to be able to understand this stuff. Any help will be very much appreciated.Wil

[Holger 0]

Hi Wil,sounds to me as if you've got a handle on ViewFinder. What is left to do is to subset the big Band 8 (15-m) image (the 4000x4000 refers to the *number of pixels* in rows and columns).I don't have Gimp so maybe others know the specifics but all you need is a display of the row/column position of the cursor when you do the cropping.Look at your reprojected image and decide on the subset area. Say, it starts at row 1000 and column 500 and will be 4000x4000 in size. Using your .tmf file above, the calculations for the NW and SE coordinate pairs are:N(subset) = 45.617072828223918 - (0.000128441000000000000 * 1000)W(subset) = -110.56070841502988 + (0.000128441000000000000 * 500)--> NW corner = 45.48863182 / -110.4964879N(subset) = 45.617072828223918 - (0.000128441000000000000 * 5000)W(subset) = -110.56070841502988 + (0.000128441000000000000 * 4500)--> SE corner = 44.97486782 / -109.9827239Make sure that you don't round to less than 6-8 significant digits (We just had this discussion in a differnt thread: people often fail to understand that small fractions of a degree still translate into substantial distances on the ground). Sorry, can't answer your question about how to combine the 30-m bands into an RGB image with Gimp. In Photoshop, you'd open one of the bands, change the type to RGB (which triplicates the grayscale image into 3 channels (not layers): red, green, and blue), and then copy and paste the other two bands into the respective channels. Paintshop even easier as it has a direct function to combine separate images to RGB.To enhance contrast and saturation, I open an individual band, switch to greyscale, and use the sliders in the Adjust > Levels function (in Photoshop).Hope that helps.Cheers, Holger

[Guest]

Howdy Holger,Let me digest your instructions and play around with an image(s) for a bit.I haven't tried Gimp yet but it has already taken over my graphics display capabilities overriding another display program that I use. I'm not sure that I appreciate this but will give it a try for a while.I'll be at Fort Laramie, Wyoming again for another two weeks begining Wednesday. I'll probably have some more questions for you after I get back.Thanks for the information and instructions.Wil

[Guest]

Hi Holger,Well, I'm stumped right off the bat. I opened the image in ViewFinder and tried to find anything looking like the row and column numbers you mention. No luck here and the TFW file remains a mystery to me. Where/how in thunder do you determine the row and column numbers?Your calculations are also beyond me and how you did them. Nothing seems to add-up.I know that it must be right there in front of me but I'll be damned if I can see it. That is what is so frustrating about this stuff for me. Never had any facility for math, geometry and other arcane subjects.Wil

[scott967 62]

I think if you select tools ... information, it will give you all the info you need. But for cropping the image, I have been using fGIS after I project the image to lat/long WGS84. When you save an image in fGIS, it also creates a .tab file with the NW/SE corners listed and all you have to do is copy/paste those into g2k4.scott s..

[Holger 0]

Howdy,"Well, I'm stumped right off the bat. I opened the image in ViewFinder and tried to find anything looking like the row and column numbers you mention. No luck here and the TFW file remains a mystery to me. Where/how in thunder do you determine the row and column numbers?"You wouldn't determine the row/column information in ViewFinder but rather in your image editor (Gimp, PSP, Photoshop) because that's where you'd do the subsetting.Scott's suggestion is a good alternative, particularly because you'd keep the georeferencing information when subsetting and thus get around the calculations.Cheers, Holger

[Guest]

Hello Scott and Holger,Thanks for the suggestions and information. I had a senior moment when I posted my previous message and later realized that I was going in a wrong direction.If the forum Administrator has any mercy at all, he'll delete that stupid post of mine.Wil