Author Topic: Inconsistent Extent  (Read 1375 times)

Grad_Student

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Inconsistent Extent
« on: January 04, 2013, 10:46:58 AM »
I was given a mosaic of Iapetus that was generated in ISIS 2. The creator of the mosaic set the Easternmost Longitude=-2; WesternMost Longitude=360 (Clong=180 & Projection=Simple Cylindrical). I clipped the mosaic in ISIS 3 using map2map. When I tried bringing the cub into ArcGIS 10 I got a “Warning, inconsistent extent!” error.

I’m not sure if I should convert the cub or if something is wrong with it.

thare

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Re: Inconsistent Extent
« Reply #1 on: January 04, 2013, 11:24:41 AM »
Since the image is going beyond 0, ArcMap is warning that this is beyond a 360 longitude range. The ISIS2 image still may work directly in ArcMap 10.x without processing in ISIS3 (even though it will also probably return an extent warning). So what maptemplate did you use to map project the image using map2map?

For using global products in ArcMap you should either set
(1) lonsys = 180 with a clon=0
or
(2) lonsys = 360 with a clon=180
Otherwise it will probably have issues with the Cartesian system.

For local areas this generally will not come up if the clon is set reasonably for the area. this related thread might help:
https://isis.astrogeology.usgs.gov/IsisSupport/index.php/topic,360.0.html

-Trent

Grad_Student

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Re: Inconsistent Extent
« Reply #2 on: January 04, 2013, 12:37:39 PM »
Hi Trent,

I guess I should back up. I first tried to bring in the ISIS2 image into Arc but got the Extent Error. So I looked at the file and noticed the longitude range was beyond 0-360.  I assumed that was why I was getting the extent issue so I decided to clip it so it wasn’t going beyond 0. When I used map2map in ISIS3 I used the Simple Cylindrical map template.  

I also installed ISIS2 and tried opening the original cub file (longitude range=-2-360) in qview but I got an error message saying it couldnt open the file.  
« Last Edit: January 04, 2013, 12:40:43 PM by Grad_Student »

thare

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Re: Inconsistent Extent
« Reply #3 on: January 04, 2013, 03:14:03 PM »
The Simple Cylindrical template is a start but you should force the parameters you want. For ArcMap, I would recommend using these parameters for a 0 to 360 longitude system.

> maptemplate map=Ia_SIMP_clon180 projection=simplecylindrical clon=180 targopt=user targetname=Iapetus rngopt=user minlat=-90 maxlat=90 minlon=0 maxlon=360

which will look like:
Code: [Select]
Group = Mapping
  ProjectionName     = SimpleCylindrical
  CenterLongitude    = 180.0
  TargetName         = Iapetus
  EquatorialRadius   = 747400.0 <meters>
  PolarRadius        = 712400.0 <meters>
  LatitudeType       = Planetocentric
  LongitudeDirection = PositiveEast
  LongitudeDomain    = 360
  MinimumLatitude    = -90.0
  MaximumLatitude    = 90.0
  MinimumLongitude   = 0.0
  MaximumLongitude   = 360.0
End_Group
End


Since the Map-a-Planet image was so small I simply requested it as a PDS image (compatible in ArcMap) and placed it here:
ftp://pdsimage2.wr.usgs.gov/pub/pigpen/iapetus/

This one is -180 to 180 which ArcMap prefers but I think you can request a 0 to 360 with a clon=180 from Map-a-Planet also.
http://www.mapaplanet.org/explorer/iapetus.html

let us know,
Trent
« Last Edit: January 04, 2013, 03:24:31 PM by thare »