topic Re: Changing / matching spatial extents in Data Management Questions

Changing / matching spatial extents

KimberlyRoberts — Wed, 14 Nov 2012 14:58:04 GMT

Hi, I have two shapefiles of the Atlantic coastline of the US that are in the same geographic coordinate systems, however their extents are different, and therefore they cannot be displayed together. One appears to be in Lat/Lon, and one in UTM. Here is what they look like:

COASTLINE 1:

Extent:
Top: 45.180969 m
Bottom: 24.501657 m
Right: -66.849304 m
Left: -97.570702 m

Data Type: Shapefile Feature Class
Shapefile: C:\NAHU_Surge_2011\CatResponse\Sandy\Coastline_shapefile\Coastline2ndpass_Full_Mar18_polyline.shp
Geometry Type: Line

Projected Coordinate System: NAD_1983_UTM_Zone_16N
Projection: Transverse_Mercator
False_Easting: 500000.00000000
False_Northing: 0.00000000
Central_Meridian: -87.00000000
Scale_Factor: 0.99960000
Latitude_Of_Origin: 0.00000000
Linear Unit: Meter

Geographic Coordinate System: GCS_North_American_1983
Datum: D_North_American_1983
Prime Meridian: Greenwich
Angular Unit: Degree

COASTLINE 2:

Extent:
Top: 5204656.913239 m
Bottom: 2723560.465375 m
Right: 2086827.768663 m
Left: -566623.472411 m

Data Type: Shapefile Feature Class
Shapefile: C:\NAHU_Surge_2011\CatResponse\Sandy\Coastline_shapefile\US_medium_shorelineUTM16_sml.shp
Geometry Type: Line

Projected Coordinate System: NAD_1983_UTM_Zone_16N
Projection: Transverse_Mercator
False_Easting: 500000.00000000
False_Northing: 0.00000000
Central_Meridian: -87.00000000
Scale_Factor: 0.99960000
Latitude_Of_Origin: 0.00000000
Linear Unit: Meter

Geographic Coordinate System: GCS_North_American_1983
Datum: D_North_American_1983
Prime Meridian: Greenwich
Angular Unit: Degree

I would like to display both shapefiles in the coordinate system and extent of Coastline 2. How can I accomplish this? I tried using the project tool to re-project Coastline 1 into Coastline 2's coordinate system, but that does not work.

Thanks,
Kimberly

Re: Changing / matching spatial extents

EricRice — Wed, 14 Nov 2012 16:25:15 GMT

COASTLINE 1:

Extent:
Top: 45.180969 m
Bottom: 24.501657 m
Right: -66.849304 m
Left: -97.570702 m

Data Type: Shapefile Feature Class
Shapefile: C:\NAHU_Surge_2011\CatResponse\Sandy\Coastline_shapefile\Coastline2ndpass_Full_Mar18_polyline.shp
Geometry Type: Line

Projected Coordinate System: NAD_1983_UTM_Zone_16N
Projection: Transverse_Mercator
False_Easting: 500000.00000000
False_Northing: 0.00000000
Central_Meridian: -87.00000000
Scale_Factor: 0.99960000
Latitude_Of_Origin: 0.00000000
Linear Unit: Meter

Geographic Coordinate System: GCS_North_American_1983
Datum: D_North_American_1983
Prime Meridian: Greenwich
Angular Unit: Degree

Kimberly,

Coastline 1 is your problem dataset. The extent is in decimal degrees. You simply cannot have data in UTM and have an extent like that. My guess is someone "defined" the coordinate system to be UTM, rather than actually "projecting" the data into UTM. You will find that if you start a blank map and add one of our basemaps to it, then add Coastline 1 data, the coastline data will not be in the right spot on the planet.

You need to clear the current projection info, then redefine the projection to be something in geographic - probably NAD83 or WGS48. Then check with our basemaps again to see if it is in the correct place.

Having different extents is common and it is not a requirement that two datasets have the same extent to be displayed together. Its ok to add one dataset in UTM and another dataset in Geographic. The key is that they must be defined correctly, and for sure, one of yours is not defined correctly. If you want to have Coastline 1 be in UTM, you have to define it first to be in what it was collected in, then you can project it into UTM. Defining the coordinate system is different than actually projecting data.

Best Regards,
Eric