How to embed a CASI Image into Mapserver

0. Assumtions 

1. Source Imagery Dataset

2. Displaying and Processing the dataset

1. File -> Open External File -> IP SOftware -> ERDAS 8.x (.img)
   
   
2. In order to get a 'close to true color' image in RGB I found following Band
   Combination most usefull:
   
   
   • R(ed): Band 7: 695 - 705 [0.695 - 0.705 µm]
   • G(reen): Band 4: 545 - 555 [0.545 - 0.555 µm]
   • B(lue): Band2 : 465 - 475 [0.465 - 0.475 µm]

Creating a Band Subset Image with ENVI

1. Display: File -> Save Image As -> Image File
   
   
2. Choosen options:
   Spatial Subset -> Image : define an area  for the new image
   
   Output Filetype: ENVI

Creating a Spatial Subset Image with ENVI

1. Display: File -> Save Image As -> Image File
   
   
2. Choosen options:
   
   Spatial Subset -> Image : define an area  for the new image [e.g. 1000 x 1000]
   
   Spatial Subset -> Map :
   (write down all spatial informations (Upper Left, Lower Right, Date, Projection)
   
   Output Filetype: TIFF

Errors

Possible Errors in Mapserver

• if no picture is generated at all, means there is not even a blank /white image:
  
  • does your mapserver application point to the right directory of the mapfile?
    
    
• if a shapefile doesn't appear: you might have used "STATUS ON " in the LAYER object in the mapfile;
  use "STATUS DEFAULT" instead
  
  

What Image output format should be used?

1. .GIF : I have no experience with .gif images, since the GD Library doesn't support this format anymore. Because of that you can't even use .gif symbology in your mapserver application. By the way: the Mapserver 3.5 tutorial dataset used to (?) include .gif symbology - so make sure the .gifs are transformed into .png and the symbology imagetype is changed.
   
   
2. .PNG : .png is probably the best overall solution for online maps. Text and geometrical objects (lines, points, polygons) are rendered very well and clear. PNG maps are easy to read and the human eye can easily distinct between colors and different objects.
   
   
3. .JPEG : Since JPEG is a great way to compress 'photo like' images, they are usefull for raster images in a mapserver application (e.g. satelliteimages ). On the other hand, they add noise and unsharpen text (e.g. on labels) and straight boundaries of objects.
   

EXAMPLES: 

Filesize and optical perception advantage of .PNG at simple spatial objects PNG outperforms in quality and filesize
Mapserver 3.6 JPEG output 26853 byte	Mapserver 3.6 PNG output 9449 byte
Filesize advantage of .JPG at 'foto like images' and complex structures JPEG offers good results at a reseanable filesize
Mapserver 3.6 JPEG output 53.901 Kbyte	Mapserver 3.6 PNG output  132.259 Kbyte

Deleting temporary files, using crontab in LINUX RedHat

1. create a little shellscript (e.g. killtemp.sh )
   
   
2. put the following 2 lines in killtemp.sh
   
   #!/bin/sh
   find /var/www/html/URGENT/temp/ -name '*.*' -type f -cmin +60 -exec rm -f - '{}' ';'
   
   #!/bin/sh - tells LINUX to use
   
   find /var/www/html/temp/ -name '*.*' -type f -cmin +60 -exec rm -f - '{}' ';'
   tells LINUX to search the temporary folder for files older than 60 min
   
   
   
3. edit your crontab:
   crontab -e
   
   
4. insert the following line, to execute killtemp.sh every 15min :
   
   0,15,30,49 * * * * /home/user/./killtemp.sh %
   ~
   .
   .
   .
   ~
   ~
   ~
   ~
   "/tmp/crontab.20542" 1L, 50C
   
   
5. make your script executeable