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[McIDAS #MHL-637032]: question about imgremap



Hi Ying,

> Thanks a lot Tom!

No worries.  I'm sorry that this has not progressed quicker...

> From the comments tag which is at the end of GeoTIFF, it says the projection
> name is north pole gnomatic projection.

You mentioned a Gnomic projection before, but I didn't know why until now.

Here is a dump of the TIFF and GeoTIFF tags included in an image created
on your machine:

geotiff read in = Geotiff file= NEXRCOMP0003.TIF
0 IFDEntry ==  tag = 256 (ImageWidth) type = SHORT count = 1 values = 1828
1 IFDEntry ==  tag = 257 (ImageLength) type = SHORT count = 1 values = 846
2 IFDEntry ==  tag = 258 (BitsPerSample) type = SHORT count = 1 values = 8
3 IFDEntry ==  tag = 259 (Compression) type = SHORT count = 1 values = 1
4 IFDEntry ==  tag = 262 (PhotometricInterpretation) type = SHORT count = 1 
values = 1
5 IFDEntry ==  tag = 269 (DocumentName) type = ASCII count = 44 
values=/usr/local/ldm/mcidas/data/NEXRCOMP0003.tif
6 IFDEntry ==  tag = 270 (ImageDescription) type = ASCII count = 27 values 
=converted McIDAS AREA file
7 IFDEntry ==  tag = 273 (StripOffsets) type = LONG count = 846 values = 8 1836
 3664 5492 7320 9148 10976 12804 14632 16460 18288 20116 21944 23772 25600 2742
8 29256 31084 32912 34740 36568 38396 40224 42052 43880 45708 47536 49364 51192
 53020
8 IFDEntry ==  tag = 274 (Orientation) type = SHORT count = 1 values = 1
9 IFDEntry ==  tag = 277 (SamplesPerPixel) type = SHORT count = 1 values = 1
10 IFDEntry ==  tag = 278 (RowsPerStrip) type = SHORT count = 1 values = 1
11 IFDEntry ==  tag = 279 (StripByteCounts) type = LONG count = 846 values = 18
28 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1
828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828 1828
12 IFDEntry ==  tag = 282 (XResolution) type = RATIONAL count = 1 values = 4194
30400/2097152
13 IFDEntry ==  tag = 283 (YResolution) type = RATIONAL count = 1 values = 4194
30400/2097152
14 IFDEntry ==  tag = 284 (PlanarConfiguration) type = SHORT count = 1 values =
 1
15 IFDEntry ==  tag = 296 (ResolutionUnit) type = SHORT count = 1 values = 2
16 IFDEntry ==  tag = 305 (Software) type = ASCII count = 13 values = geotapu
t 1.0
17 IFDEntry ==  tag = 306  type = ASCII count = 20 values = 2006:02:06 14:46:
00
18 IFDEntry ==  tag = 33550 (ModelPixelScaleTag) type = DOUBLE count = 3 values
 = 0.035991 0.035991 0.0
19 IFDEntry ==  tag = 33922 (ModelTiepointTag) type = DOUBLE count = 6 values =
 0.0 0.0 0.0 -129.22116088867188 52.20180892944336 0.0
20 IFDEntry ==  tag = 34735 (GeoKeyDirectoryTag) type = SHORT count = 48 values
 = 1 1 0 11 1024 0 1 1 1025 0 1 1 1026 34737 68 0 2048 0 1 4326 2049 34737 12 6
8 2057 34736 1 0 2058 34736
         geoKey = 1024 (GTModelTypeGeoKey) value = 1 (Projected)
         geoKey = 1025 (GTRasterTypeGeoKey) value = 1 (Area)
         geoKey = 1026 (GTCitationGeoKey) values = RADAR        2006/02/06 14:4
6:00 Band=31 Calibration: BRIT  Scale=0|
         geoKey = 2048 (GeographicTypeGeoKey) value = 4326 (WGS_84)
         geoKey = 2049 (GeogCitationGeoKey) values = McIDAS RECT|
         geoKey = 2057 (GeogSemiMinorAxisGeoKey) values = 6378388.0
         geoKey = 2058 (GeogInvFlatteningGeoKey) values = 6356911.888395185
         geoKey = 3072 (ProjectedCSTypeGeoKey,) value = 32767 (UserDefined)
         geoKey = 3074 (ProjectionGeoKey,) values = 32767
         geoKey = 3075 (GeoKey_ProjCoordTrans) values = 17
         geoKey = 3076 (ProjLinearUnitsGeoKey) value = 9001 (Meter)

21 IFDEntry ==  tag = 34736 (GeoDoubleParamsTag) type = DOUBLE count = 2 values
 = 6378388.0 6356911.888395185
22 IFDEntry ==  tag = 34737 (GeoAsciiParamsTag) type = ASCII count = 81 value
s = RADAR        2006/02/06 14:46:00 Band=31 Calibration: BRIT  Scale=0|McIDAS
RECT|

Both the ProjectedCSTypeGeoKey and ProjectionGeoKey tags indicate a user
defined projection, not Gnomic.

> There IS such projection in ArcGIS, but I failed to set it to the GeoTIFF
> images. There might be problems in the parameters so ArcGIS doesn't
> recognize it.

I think that ArcGIS 9 and previous may be treating the user defined projection
incorrectly.  ArcGIS 9.2 beta appears to understand that this is a user defined
projection.

> If I know the value of these parameters(i.e. the center's position in
> long/lat), I believe the image could be projected correctly after i
> adjust the parameters.

Hopefully, the dump of values I provided above will contain parameters
that are useful.

re: UPC was able to display the image with a map 
> Is it related with database? Could I know what database did you load for that?

Since I am a total novice wrt ArcGIS, I will not be of much help here.  I 
believe
that we used a census database that contained US maps in Lat,Lon projection
(don't know the specific ArcGIS name right off).  The procedure we used to
load the GeoTIFF and add map was:

- start ArcMAP with a blank template
- bring in the GeoTIFF
- stretch the colors (from gray scale to color)
- add a map database (this is where I am hazy since I was not doing the steps
  myself)
- play with the map layer to turn off features we did not want (like cities,
  counties, etc.)
- change the map background to hollow (transparent)

After doing this, we ended up with a display of the NTP features overlaid
with a correctly possitioned map.  We compared precipitation features with
state borders against displays in McIDAS and saw that the mapping was correct.
Our conclusion was that ArcMAP 9.2 beta could be used to display the images
and also display features in other layers.  Beyond this, we can not say much
more since we are total novices when it comes to ArcGIS.

re: McIDAS RECTilinear projection
> I was planning to overlay some other spatial data with the NEXRCOMP data.
> And projections like Plate Carree Projection is preferred.

McIDAS does not support the Plate Carree projection, sorry.

> So I need to
> reproject the GeoTIFF to that projection. In case you know the parameters
> of the RECTlinear projection, could you let me know about it?

Does the tag listing above help?

> thanks and regards!

No worries.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: MHL-637032
Department: Support McIDAS
Priority: Normal
Status: Closed


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