topic Re: change the projection of a shapefile in Data Management Questions

change the projection of a shapefile

Kiriaki-MariaFameli — Wed, 26 Oct 2011 10:37:12 GMT

I am a new user of GIS and I have a polyline shapefile with roads in GCS_WGS_1984 geographic projection and I want to extract part of it (only the motorways) in a new shapefile with projection Lambert Conformal Conic in order to calculate the length of each polyline. How can I extract the information I need and save it in a different projection from the one the initial shapefile has?

Re: change the projection of a shapefile

RichardFairhurst — Wed, 26 Oct 2011 14:03:16 GMT

I am a new user of GIS and I have a polyline shapefile with roads in GCS_WGS_1984 geographic projection and I want to extract part of it (only the motorways) in a new shapefile with projection Lambert Conformal Conic in order to calculate the length of each polyline. How can I extract the information I need and save it in a different projection from the one the initial shapefile has?

First I assume there is an field in the attribute table that classifies the roads to that you can create a query to select the motorways only. You can use either the Selection menu item for Select by Attributes or open the layer's table and use the Select by Layer in the table. After you have the correct layer as your target build an SQL expression to do the selection. Something like:

ROAD_CLASS = 'MOTORWAY'

Once all of your Motorways are selected, you can right click the layer in the Table of Contents and choose Data then Export. Browse to the directory where you want the shapefile to be, give the new file a name and choose shapefile as the type of file to export. Hit OK and you have a new shapefile with just the motorways you selected.

Re: change the projection of a shapefile

Kiriaki-MariaFameli — Thu, 27 Oct 2011 09:39:48 GMT

Thanks a lot for the advice. I did as you suggest but the new shapefile has the projection of the initial shapefile(which is GCS_WGS_1984) and I want the new shapefile (with the motorways)to have Lambert projection. How can I change and save the projection of the new shapefile?

Re: change the projection of a shapefile

MattMorris — Thu, 27 Oct 2011 12:43:52 GMT

Set your data frame projection to the one you want; when you export the shp file, check the "use the data frame projection" button. Or, you can re project in Arc Toolbox, Data Management Tools, Projections and Transformations, Project. It's a lot simpler to just use the data frames projection though, and the result is the same.

Re: change the projection of a shapefile

Kiriaki-MariaFameli — Mon, 31 Oct 2011 09:27:28 GMT

Thanks a lot!The new shapefile has the projection I want.