Friday, 5 February 2016

arcgis desktop - Projected maps should but do not overlap in ArcMap?



I am very new to ArcGIS and trying to build a series of layers of data in ArcGIS 9.3.1 for a river catchment in Leicestershire, using data from several sources. All data covers at least the area of interest.


I have maps using British_National_Grid and NAD_1983_Albers as the projected co-ordinate system. When projected together one British National Grid layer doesn't all appear with the others. The Albers layers match the majority of the National Grid layers.


As far as I can tell the National Grid layers data (see below) is the same for all.



Data Type: Shapefile Feature Class Shapefile: C:\luke-work\Analysis 2 data\aquatic landscapes\AquaticLandscapes.shp Geometry Type: Polygon


Projected Coordinate System: British_National_Grid Projection: Transverse_Mercator False_Easting: 400000.00000000 False_Northing: -100000.00000000 Central_Meridian: -2.00000000 Scale_Factor: 0.99960127 Latitude_Of_Origin: 49.00000000 Linear Unit: Meter


Geographic Coordinate System: GCS_OSGB_1936 Datum: D_OSGB_1936 Prime Meridian: Greenwich Angular Unit: Degree




The other two projections data are



Data Type: Personal Geodatabase Feature Class Location: C:\luke-work\Analysis 2 data\catchment\catchment.mdb Feature Dataset: Layers Feature Class: DrainageLine Feature Type: Simple Geometry Type: Line


Projected Coordinate System: NAD_1983_Albers Projection: Albers False_Easting: 1500000.00000000 False_Northing: 6000000.00000000 Central_Meridian: -100.00000000 Standard_Parallel_1: 27.50000000 Standard_Parallel_2: 35.00000000 Latitude_Of_Origin: 18.00000000 Linear Unit: Meter


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



Any suggestions on what I am doing wrong?




Thanks for your answer. I have tried out what was suggested and answer each comment below.


2). I only have GIS data for the UK that I am looking at currently, so have had to assume (seperately) that each data set is OK, and it is the other that is mis-behaving (i.e. everything has been done twice). Is this even a safe approach.



4). No, data for catchment is still projected about 100 miles south west of where it should be.


6). No. data remains in the wrong place.


Subsequent comments: Data seems to be scaled appropriately - UK is larger than catchment!


Further investigation of the data I was given also reveals that there is a dataset which is projected significanly south west of the data in the above problem (now referred to as "Drain"). I am guessing somehere in Brazil! This appears (to me) to be using the same co-ordinate system as the catchment. This is backed up (in my mind) by the fact that is has previously been used in a modelling exercise for the catchment. That work was carried out on a different computer at a different site (would this even be significant?).


Catchment data:



Data Type: Personal Geodatabase Feature Class Location: C:\luke-work\Analysis 2 data\catchment\catchment.mdb Feature Dataset: Layers Feature Class: Catchment Feature Type: Simple Geometry Type: Polygon


Projected Coordinate System: NAD_1983_Albers Projection: Albers False_Easting: 1500000.00000000 False_Northing: 6000000.00000000 Central_Meridian: -100.00000000 Standard_Parallel_1: 27.50000000 Standard_Parallel_2: 35.00000000 Latitude_Of_Origin: 18.00000000 Linear Unit: Meter


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




Drainage:



Data Type: Personal Geodatabase Feature Class Location: C:\luke-work\Analysis 2 data\catchment\catchment.mdb Feature Dataset: Layers Feature Class: DrainagePoint Feature Type: Simple Geometry Type: Point


Projected Coordinate System: NAD_1983_Albers Projection: Albers False_Easting: 1500000.00000000 False_Northing: 6000000.00000000 Central_Meridian: -100.00000000 Standard_Parallel_1: 27.50000000 Standard_Parallel_2: 35.00000000 Latitude_Of_Origin: 18.00000000 Linear Unit: Meter


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





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