Latest Contributions by grahamlangley-edwards

Hi, I am attempting to orthorectify several satellite images.  I have read the help sections on orthorectifying but the images don't have RPC values, so none of the options described will work.  For example, the orthorectify button is greyed out.  Is there a way that I can calculate RPC values for these images to orthorectify them?  Or is there another way to do it without RPC values?  Some info about the images, Number of bands - 3 Cellsize (X,Y) - 1,1 Format - JFIF Pixel type - Unsigned integer Pixel depth - 8 bit I have Built pyramids for the images and calculated statistics.  Any help would be appreciated. Thanks, Graham ... View more

Hello, I am using ArcGIS 10 and have several orthoimages (Landsat 4-5 TM) that I got from the GLOVIS site that I need to mosaic together and orthorectify.  I don't have any experience with this, so some questions may be relatively basic.  Some info about the images that may be helpful:  Number of bands - 3 Cellsize (X,Y) - 1,1 Format - JFIF Pixel type - Unsigned integer Pixel depth - 8 bit Pyramids - Absent Statistics have not been calculated From what I understand, I need images that have RPC (Rational Polynomial Coefficient) values, and a DEM in order to orthorectify them. The images, however, have no RPC values associated with them, although I do have a DEM I can use.  The images also don't have any spatial reference, so I can't mosaic them together.  Furthermore, I have no idea what the original geographic coordinate system was, so I can't use Define Projection to rectify that problem.  Basically I need to know if it is possible to orthorectify images that don't have RPC values, or if I can calculate them, and how I can figure out a spatial reference for the images as well. Any help would be much appreciated! Graham ... View more

Hi, I am trying to generate a unique id field, in ArcGIS 10, in order to run an OLS regression.  I created a new unique id field in the attribute table of the point shape file.  I then tried to generate values for it using the field calculator and the FID field (UniqueID = FID), the FID field has different values for each row.  The process begins, but half way through I get this error - " The calculated value is invalid for the row with object ID = 32768.  For example, the calculated value may be too large for the field or you may be trying to add a string to a number field.  This row will not be updated." When I look at the unique id field after the process has run, the values go up to 9999 and then begin again at 1000.  Apparently, the field calculator is not "seeing" the entire number in the cells with more than 4 numbers, and assigns only the first 4 number in the FID field to the Unique ID field. Then at entry 32768, it begins assigning values of 0 to the Unique ID field.  There are 41,643 entries.  I tried using other fields that also have different values for each row to generate the Unique ID field, but the same problem happens.  I don't see how the calculated value could be too large for the field, and I am not trying to add a string to a number field.  I also cannot delete any of the Unique ID fields that I created in the attribute table, I tried right-clicking on the field and clicking delete to no avail.  Any help would be greatly appreciated. Thanks ... View more