[Gvsig_english] copying shape file layers

[Robert Sanson]

Hi Simon
 
If you come from an ArcView 3.x background (as I do),  then GvSIG behaves in a similar manner (both in terms of layers and the Project Manager). Copy merely copied the layer in the View, not the underlying Shapefile.
 
I think later versions of ArcMap also allow you to have multiple layers derived from the same underlying datasource, that you can symbolise differently etc. If you actually want to create a whole new Shapefile on disk, then you need to use Save As.
 
Regards,
 
Robert Sanson

>>> "Simon Cropper (The fosGIS Workflow Guides)" <scropper at botanicusaustralia.com.au> 3/08/2011 12:29 p.m. >>>
On 02/08/11 17:00, Benjamin Ducke wrote:
> I disagree. A layer IS a reference (to e.g. a Shapefile).
> There is no such thing as a reference to a layer.
> A Shapefile is not a layer. It's a dataset comprising
> several files. A layer is an abstract concept in GIS,
> not physically existing data.
>
> In this case, gvSIG does use the right terminology,
> and it should stay that way.
>
> Also, "Copy" is the right name for the function. It
> is in the context menu of a layer, so it clearly
> copies a layer (and nothing else). Your word processor
> does not say "Copy text" either. It simply says "Copy",
> yet nobody expects it to be copying the actual file.
> Likewise, nobody thinks its "Format" function is
> for formatting the hard disk.
>
> It makes sense to separate the concepts of layer
> and dataset. A gvSIG layer can reference many
> types of datasources: a table in a spatial DBMS,
> a WMS data stream, etc., etc. How would you implement
> a "Copy" function of physical data for these?
>
> If you want to have an actual copy of your Shapefile,
> either use your file manager, or use "Save as"
> (now, this one should really be called "Save data"!)
> from gvSIG's "Layer" menu.
>
> Ben

Hi Ben,

I respectfully disagree.

Any GUI element (e.g. button, dialog), function or documentation that 
causes confusion should be clarified.

I get what you are saying but if people are confused then something 
needs to be done to avoid this situation.

Assume you are a newbie that wants to view a vector file - 'roads'. You 
download gvSIG and through a little experimentation get the vector file 
to open in a view.

OK. You want to copy the file so you can edit the copy. How?

OK. You know the vector file is a shapefile so you close gvSIG then copy 
the file roads.shp to roads-new.shp, open gvSIG and try and open the 
file. The process does not work. roads-new.shp does not open.

You look at the directory and see extra files of the same name - that is 
roads.shp, roads.shx and roads.dbf. Should you copy and rename all these 
files? OK, but why do other file collections have more files? Confusion 
rains.

Obviously if users reads the manual, researches shapefiles, etc then 
these questions would be answered pretty quickly but lets face it most 
people don't do this; they just open the program and use it.

In the absence of a duplicate shapefile feature in the project window or 
main menu, users will gravitate to anything that states 'copy'. Using 
your example of copying text in a word processor document. If a user 
highlights some text, copies it then pastes it elsewhere in the 
document, they can edit this version of the text separately from the 
original. Most users would expect that if you can see a block of data 
and copy it, you should be able to edit the copy safely without 
influencing the original. This is exactly what Klaus did.

When you find a menu option that allows you to 'copy' a shapefile you 
expect that this is what it does. If all it does is copy the reference 
to a shapefile then the menu option should state this. What harm would 
it do the be more explicit? If a newbie found a menu option called 'copy 
ToC reference' instead of 'copy' they would automatically know that it 
did not copy the file.


In addition, gvSIG requires an extension or main menu option called 
'Manage Files' that would allow you to copy and rename your shapefiles. 
I remember ArcView use to have an extension like this.

The suggestion, proposed later in the thread, for a separate file 
manager is a good idea but does not negate the need for some basic 
functionality somewhere in the main GUI of gvSIG.

*Extra Ramblings*

Something I never quite understood with gvSIG is the fact that there is 
a list of views, maps and tables in the project manager. To me it would 
be logical to have a list of data sources (shapefiles, tables, database 
connections), views, maps and/or derived documents (pdfs, images and 
tables). This would better represent a normal workflow.

With the status quo, views show you your data, maps show you your 
representation of this data and tables the attribute data of shapefiles 
referenced in your view and/or unique tables referenced on your file 
system and/or derived data (e.g. summary tables). What's listed in the 
tables list is very messy and confusing.

Having the project manager better reflect common workflow practices 
would make using gvSIG so much easier.

List 1. define data you want to use (shapefiles, databases, CAD, tables)
List 2. define data views including Coordinate Reference System
List 3. define and track different data conversions and analysis.
List 4  define and track derived project data (maps, images, graphs,
         pdfs, tables). As maps are common outputs from most projects,
         retaining a separate list of maps may be warranted.

Just a thought...

-- 
Cheers Simon

    Simon Cropper
    Website Administrator
    http://gis.fossworkflowguides.com 
    The fosGIS Workflow Guide
    (c) Simon Cropper CC-BY-SA 3.0 Australia
    http://creativecommons.org/licenses/by-sa/3.0/au/deed.en 
_______________________________________________
Gvsig_internacional mailing list
Gvsig_internacional at listserv.gva.es 
http://listserv.gva.es/cgi-bin/mailman/listinfo/gvsig_internacional


This email and any attachments are confidential and intended solely for the addressee(s). If you are not the intended recipient, please notify us immediately and then delete this email from your system.

This message has been scanned for Malware and Viruses by Websense Hosted Security.
www.websense.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://listserv.gva.es/pipermail/gvsig_internacional/attachments/20110803/61d91c53/attachment.htm