Hi
I have a similar problem.
I have one dataset with environmental data in a WGS 1984 UTM zone.
I am trying to add another environmental data layer from a netcdf file (works fine with the make netcdf raster layer) but the projection is off. Importing it "on the fly" into the existing dataset do not work. Projecting, reprojecting and exporting it do not work.
The information with the netcdf file states that it uses the "native tripolar grid (ORCA025) at ¼° resolution with 75 vertical levels" as the only info. What kind of projection is that?
Clearly someting is wrong with my projection
Old data set
extent :
Top : 9501969,24636
Bottom: -1831567,57809
Right: 3230932,42191
Left: 5176969,24636
New netcdf file
extent :
Top : 188,5
Bottom: 0,5
Right: 177,5
Left: 0,5
Helle
At first glance, I thought these were GCS (geographic) coordinates, but that doesn't look correct.
New netcdf file
extent :
Top : 188,5
Bottom: 0,5
Right: 177,5
Left: 0,5
Bottom left is 0.5, 0.5. Top right is 177.5, 188.5
Doesn't look like anything to me. Are you sure this data is actually georeferenced to anything.
And, those numbers on your original data don't look anything like i would expect from UTM. Have you actually looked at this data with some other background info to confirm that it is where you think it is?
Hi Neil
Thank you for taking time to reply.
Yes I agree with the weird numbers. It might be a problem with references missing in the net.cdf file (which is generated in Matlab after data has been assembled) nccreate and ncwrite were used in matlab to build the file. I am not sure excatly what is missing as ARCGIS plots the data but it is "to small" and totally off - so I think something must be added when building the net.cdf file.
The orginal data plots fine with a worldmap and should be ok.
Helle
If those original coords are utm, then it is about 6 or 7 zones to the right of the zone you are using. Might be considerable distortion in your data.
Hello Helle,
Did you find this site: CM2.X model ocean and sea ice grids information
You might want to check whether they've exported the variable you want into a rectangular grid-based file.
Melita
Hi!
I am facing troubles re-projecting vector data from USGS HYRO1k for Africa to WGS84. The projection doesn’t match with correct WGS84 maps (about 3 miles east offset). Have tried all kinds of transformations and re-definitions of the original projection, though without success.
Shapefile 1:
Sphere_ARC_INFO_Lambert_Azimuthal_Equal_Area
Authority: Custom
Projection: Lambert_Azimuthal_Equal_Area
False_Easting: 0,0
False_Northing: 0,0
Central_Meridian: 20,0
Latitude_Of_Origin: 5,0
Linear Unit: Meter (1,0)
Geographic Coordinate System: GCS_Sphere_ARC_INFO
Angular Unit: Degree (0,0174532925199433)
Prime Meridian: Greenwich (0,0)
Datum: D_Sphere_ARC_INFO
Spheroid: Sphere_ARC_INFO
Semimajor Axis: 6370997,0
Semiminor Axis: 6370997,0
Inverse Flattening: 0,0
Data is from USGS Earthexplorer – Digital Evelation – GTOPO30 –HYDRO1k https://lta.cr.usgs.gov/HYDRO1KReadMe
Any ideas? Your help is highly appreciated.
Thanks a lot & best,
Uli
Hello all,
I've read through all past posts going back years, and unfortunately none of the prior fixes worked for me. This thread has been alive and well for years, hopefully someone is still out there to provide a little insight!
I have two polygon shapefiles with the same coordinate system:
WKID: 32651 Authority: EPSG
Data Type: Shapefile Feature Class
Geometry Type: Polygon
Coordinates have Z values: No
Coordinates have measures: No
Projected Coordinate System: WGS_1984_UTM_Zone_51N
Projection: Transverse_Mercator
False_Easting: 500000.00000000
False_Northing: 0.00000000
Central_Meridian: 123.00000000
Scale_Factor: 0.99960000
Latitude_Of_Origin: 0.00000000
Linear Unit: Meter
Geographic Coordinate System: GCS_WGS_1984
Datum: D_WGS_1984
Prime Meridian: Greenwich
Angular Unit: Degree
The two shapefiles should overlap, however their extents are different:
File 1 (the "correct" file):
Top: 1255609.389774 m
Left: 707424.654017 m
Right: 721689.696680 m
Bottom: 1237012.701112 m
File 2:
Top: 63404.759644 m
Left: -15831.190479 m
Right: 20830.738005 m
Bottom: -17715.538242 m
When I activate both layers, they are offset by thousands of meters. I can also tell that File 2 is sized incorrectly, it's scaled significantly larger than file 1. I received these files from a local city government, I wanted to use their shapefiles to recreate some maps for spatial analysis. It's a wonder to me that they created the maps they did when the extents are so different.
Any advice would be greatly appreciated!
Shaye
Is the data approximately 10 km west of Palo, in the Philippines?
I looked at the other coordinate systems that we support for the Philippines, but none of them match the coordinates of your second dataset. The fact that it has negative and positive values implies that its center is in the area, so not a standard UTM or Philippines zone.
I have found some references to local cadastral grids/projections, so it's possible that is what the second data is using. You'd have to find out the parameters. I think the origin is usually the first point of the cadastral survey.
Melita
Hi Melita,
Thank you for your reply, and for all the insight you've contributed to this thread. No, the data is not west of Palo, but more like 20 km north of Palo. I have reached out to the creator of the dataset to inquire about the potential use of local cadastral grids/projections. I'll reply with updates should that work as we figure it out, so others with similar issues might learn as well.
Thank you!