topic Re: Shape file Projection problems in Coordinate Reference Systems Questions

Shape file Projection problems

NeilBombardier — Wed, 15 Oct 2014 02:15:17 GMT

Afternoon everyone,

I have 2 shape files which are not aligning correctly, despite having used the Project tool to reprojected both the projected coordinate systems and the geographic coordinate systems. Can anyone advise what I might be doing wrong. Thanks

File one

Projected Coordinate System: AGD66_AMG_zone_54

Projection: Transverse_Mercator

false_easting: 500000.00000000

false_northing: 10000000.00000000

central_meridian: 141.00000000

scale_factor: 0.99960000

latitude_of_origin: 0.00000000

Linear Unit: Meter

Geographic Coordinate System: GCS_Australian_1966

Datum: D_Australian_1966

Prime Meridian: Greenwich

Angular Unit: Degree

File two

Projected Coordinate System: AGD66_AMG_zone_54

Projection: Transverse_Mercator

false_easting: 500000.00000000

false_northing: 10000000.00000000

central_meridian: 141.00000000

scale_factor: 0.99960000

latitude_of_origin: 0.00000000

Linear Unit: Meter

Geographic Coordinate System: GCS_Australian_1966

Datum: D_Australian_1966

Prime Meridian: Greenwich

Angular Unit: Degree

Re: Shape file Projection problems

OwenEarley — Wed, 15 Oct 2014 05:47:53 GMT

It appears that you have projected both files to the same coordinate system (AMG Zone 54 with the AGD66 datum). The issue may be the input data sets.

Did the input data sets share the same coordinate system (including datum)?

If they had different coordinate systems then one of the datum transformations when projecting may be the issue. If the input data did have the same coordinate system and you applied the same projection parameters then they should line up.

Re: Shape file Projection problems

NeilBombardier — Wed, 15 Oct 2014 07:25:02 GMT

How do I check the input data sets coordinate systems - I'm a relatively novice user

Re: Shape file Projection problems

OwenEarley — Wed, 15 Oct 2014 21:56:15 GMT

Add one of the input data sets to ArcMap and then right-click on it in the layers list, select Properties and then click on the Source tab:

This will show the coordinate system of your input data. Do this for both inputs and see if they are the same.

Re: Shape file Projection problems

DarrenWiens2 — Wed, 15 Oct 2014 22:27:16 GMT

As Owen alludes to, make sure your data is first defined correctly (according to the original data) and then projected properly, if necessary. See this Knowledge Base article:

When do I define a projection, and when do I project data?

Re: Shape file Projection problems

MelitaKennedy — Thu, 16 Oct 2014 21:31:09 GMT

Neil,

Step back to the original data with their original coordinate systems. If you can't get them to overlay properly, check if you can get either one to line up with some reference data that you know is correct. That should tell you which one doesn't have its correct coordinate system. For that one, please post its extent, plus the general location that it represents.

Melita