Jump to content

Orthorectification Step by Step


Daniela_06

Recommended Posts

Hello everyone,

I am going crazy with this orthorectification procedure. This is what i have. I have several satellite images TM and ETM+ from different years that i need to classify and the perform change detection techniques.

This images are 30m resolution. UTM Zone 30N WGS1984.

I also have gather 2 DEM 1 arc sec (approx 30m ) UTM WGS1984. I need to do a mosaic of this two DEM because together cover the area of each satellite images. But not exactly. This to DEMS together are only a portion of the area of each satellite image, but it covers the area that i need. (NOT ALL THE SATELLITE IMAGE IS NEEDED).

1. Do I have to reproject the mosaic DEM to UTM ZONE 30N WGS1984 first?

2. I am using ENVI 4.2 and I am doing an Automated Image to image registration. This generates automatic GCP in the DEM and relates this GCP to the Satellite image (Band 1 for example)

3. The table of GCP shows a error of 25.50m is this to much of an error? because the images are 30m.

4. I have done the registration with this values and obtain a quite similar image than the original.

Can anyone tell me if my procedure is correct? If its not, can someone explain me step by step how to do an orthorectification. I have seen tutorials, but ENVI 4.2 does not have USGS images or Landsat satellites listed to do orthorectification as all the tutorial shows. I need a more step by step (orthorectification for dummies)

Thank you very much, I am really losing my mind here.

Link to comment
Share on other sites

Change you envi program to the v4.8 or v5..Download the rigorous orthorectification module

-change the landsat image projection to the dem projection...(you can do this job on fly with envi)

-Now you can use the tool to orhorectify your portion of satellite images...

Link to comment
Share on other sites

  • 4 weeks later...
  • 5 months later...

Help: I need to orthorectify a IRS-P6-LISS-IV standard imagery. As no RPC file is associated with the image therefore, in Erdas Imagine 2011  I went for the "Orthorectify without GCP" tab. Here I have chosen "Orbital Pushbroom" as geometric model. Here message is coming "Failed to get metadata for the image. Can anyone tell me where I go wrong?? Thanks in Advance.

Edited by swagata
Link to comment
Share on other sites

  • 3 years later...

I don't think your problem is orthorectification for what you want to perform.

Before you can do classification and change detection you need to do:

  1. Convert DN to radiance
  2. Convert radiance to reflectance
  3. Then you can do NDVI, Classification, change detection, comparison etc. between sensors and temporal resolutions
Link to comment
Share on other sites

I'm getting the "failed to get metadata" error as well. In Erdas Imagine 2016. Doing the same procedure as Daniela_06 with SRTM30 and WV2 imagery. 

Hi,

 

This problem happens because, probably you don't have the metadata file , it's more or less like , the file where you have the info about your image. In the case of WV2, you could have a TIL file with another RPC/RPB file and i think that you could probably have a IMD file and of coarse the tiff file.

 

Then the program had to read all this files to process your image correctly. 

 

 

 

I hope it help...

Link to comment
Share on other sites

Hi,

 

This problem happens because, probably you don't have the metadata file , it's more or less like , the file where you have the info about your image. In the case of WV2, you could have a TIL file with another RPC/RPB file and i think that you could probably have a IMD file and of coarse the tiff file.

 

Then the program had to read all this files to process your image correctly. 

 

 

Thanks, yes I've now realized that that is the problem.

 

I have a number of WorldView images from Digital Globe. They are labelled as R1C1, R2C1 etc. and all end in P001. I have a metadata file (.imd) but only for P001 and not for each individual image. I have tried mosaicing all the WorldView images together to form a single file for P001 but am still having trouble reading the metadata file (error: Failed to getmetadata). 

 

I can view the metadata in ERDAS. 

Edited by Annjeand
Link to comment
Share on other sites

Thanks, yes I've now realized that that is the problem.

 

I have a number of WorldView images from Digital Globe. They are labelled as R1C1, R2C1 etc. and all end in P001. I have a metadata file (.imd) but only for P001 and not for each individual image. I have tried mosaicing all the WorldView images together to form a single file for P001 but am still having trouble reading the metadata file (error: Failed to getmetadata). 

 

I can view the metadata in ERDAS. 

Hi again,

 

You could create a single file from all your R1C1, R2C1, etc... with gdal it's more or less like this 

 

gdalbuildvrt yourfile.vrt *.tif

 

then export to a tif file (becareful it could be huge)

 

gdal_translate -of gtiff yourfile.vrt destinationfile.tif (you give the name of your imd file with extension .tif)

 

Then you could use the file in ERDAS...

 

See you

Link to comment
Share on other sites

  • 2 months later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.

Disable-Adblock.png

 

If you enjoy our contents, support us by Disable ads Blocker or add GIS-area to your ads blocker whitelist