Using spatial reference system / shapefile projection

Question

I am new to using QGIS and having some problems getting some shapefiles to project correctly. I am using publicly available shapefiles for New York City municipal boundaries found here: http://www.nyc.gov/html/dcp/html/bytes/dwndistricts.shtml (ie borough shapefile)

When I download and add the shapefile to my project, the shape is projected in an inaccurate geographic location (as in WAY off).

The extents read as: 835386,112481 : 1144283,277548

And the metadata says:

"General: Storage type of this layer: ESRI Shapefile Source for this layer: /Users/Koren Manning/GIS/nybbwi_12a_av/nybbwi.shp Geometry type of the features in this layer: Polygon The number of features in this layer: 5 Editing capabilities of this layer: Add Features, Delete Features, Change Attribute Values, Add Attributes, Delete Attributes, Create Spatial Index, Fast Access to Features at ID, Change Geometries Extents: In layer spatial reference system units : xMin,yMin 912287.07,116411.37 : xMax,yMax 1067382.51,273617.84 Layer Spatial Reference System: +proj=lcc +lat_1=40.66666666666666 +lat_2=41.03333333333333 +lat_0=40.16666666666666 +lon_0=-74 +x_0=300000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=us-ft +no_defs"

This doesn't make a lot of sense to me but it clearly seems like something is off with the spatial reference system. I tried changing the coordinate reference system to EPSG:4269 - NAD83 which is what other shapefiles I was using were in (from a different source) but this did not change the projection.

Any idea what I am doing wrong?

• Melita Kennedy: I don't know whether it helps, but a possible EPSG code for that coordinate reference system is 2263 (NAD83 / New York Long Island (ftUS)).

Answer 1

Select EPSG 4269 as your Coordinate Reference System. (Settings-Project Settings - Coordinate Reference System EPSG:4269 and important: enable on the fly CRS transformation. Now load your new york shape file done:Ney York in EPSG 4269

• Koren: Thanks so much for your response. I was able to change the project settings to the correct coordinate system, however the shapefiles themselves are still projecting in coordinates that are way off.
• Kurt: can you upload one of your other shapefiles as zip, so we can take a look at this?

Answer 2

EPSG 4269 is a CRS based on lat lon coordinates, and the one you describe before is on us feet, also origin of coordinates are different. If you want to reproject the one in feet load this layer, then choose it, right click on it, and then choose save as. Format is the same (shp) In the CRS Section choose EPSG:4269. Sometimes people think that using "set layer crs" (right click on the layer) or "specify crs" (in layer properties/general tab) means that they are reprojecting. This is not the case. Reprojecting means change from one coordinate system to another that can have different measuring units, datums, origins and projections. The method described above should reproject correctly your file

• Koren: Thanks so much for your response. I tried this but the file is still projecting with coordinates that are way off. (the extent is 840236,116304 : 1140322,276662).
• Micha: The original does seem to be in an unusual CRS, but QGIS recognized the projection data fine (as you saw in metadata) so all you need to do is reproject to 4369. Do NOT change the coordinate system - as Gerardo explained this does not reproject. Make sure you do NOT have any nybb.qpj file with the shapefile, then reproject, as Gerardo explained, by RightClick -> Save As and choose the CRS as EPSG:4269. The new shapefile should overlay your other data OK.

Answer 3

Taking the "nybbwi.shp" shapefile as an example, QGIS is interpreting the data in the .prj file correctly and using this to make a custom CRS. So load the file, right-click on it in the layers panel and go "Set project CRS from layer". Then enable on-the-fly coordinate transformation.

From the above, I gather that you have some shapefiles in EPSG:4269 that you wish to add to the project. All you should now need to do now is load these into the project, where they should transform on-the-fly to the projection of "nybbwi.shp".

If the EPSG:4269 data does not align properly with the "nybbwi.shp" shapefile it means that QGIS is not recognising its CRS, so manually set the CRS of these layers to EPSG:4269.