[Freegis-list] Re: GRASS still quite far from usable

[Markus Neteler]

On Mon, Sep 12, 2005 at 12:27:14PM -1000, Ben Discoe wrote:
> Markus,
> 
> Thanks for trying to help.
> 
> > -----
> > From: Markus Neteler
> > Sent: Monday, September 12, 2005 11:38 AM
> > 
> > > was able to generate tons of cryptic errors about command-line 
> > > arguments, but could not get a single line to be drawn.
> > 
> > Consider to post the error, otherwise I can't help much :-)
> 
> First, i get "ERROR: Required parameter <map> not set."  If i select my
> imported vector (again..) in the 'Name of input vector' field, then i get
> "No socket to connect to for monitor <x0>: No graphics device selected.

The last message means that you have to select a graphics device
(which can be a GRASS monitor, the PNG output etc). The d.mon command
will help you (select x0 for example). Or: use the d.m GIS manager
which will *automatically* open a monitor.
 
> I can almost understand having to tell GRASS which layer to draw (although
> it's unfriendly, i simply want to draw the data i've got, which should be
> obvious.)

It's not always obvious: if you have 1-thousands of maps in your mapset,
which one to draw? In many computer software programs which can operate
with several input files (alias maps), the user has to choose or has
to define a rule how to choose (alias script programming).

> However, i don't understand GRASS having to be told that i have a
> monitor(?!) 

Again, use the d.m GIS mananger (which is *automatically* opened
when starting GRASS with a location). Or use QGIS or use JAVAGRASS or ...

> Is this something left over from the early 1970s when graphics
> output was not always available?

In fact the "GRASS monitor" is the graphics output (exists since the
early 1980s).

> > > GRASS opens with a window titled "GRASS 6.0.0 GIS 
> > > Manager - spearfish60".  Nothing is displayed in the window
> > > - not graphics, not a list of layers, nothing!
> > 
> > Sure. How should GRASS know which of the many maps the user 
> > wants to see?
> 
> If i load a set of layers, it shouldn't show me what layers i've loaded?
> This doesn't make any sense at all.

I think it does...

> > Not even ArcView starts with displaying a map 
> > but just with the user interface.
> 
> ArcView shows you what layers exist,

GRASS does the same.


> and as soon as you turn on a layer,
> it's drawn.  This is really obvious and easy.

Same thing in the GIS manager, in QGIS, in JAVAGRASS.

> > > I looked for, but could not find any command to Zoom
> > > All, or otherwise draw the data
> > 
> > There are:
> > - in d.m: a magnifying glass symbol [1]
> 
> I was looking for a Zoom All because i was guessing that GRASS wasn't smart
> enough to start the view with the full extents of the data. 

This is intentionally. The GIS cannot know which part of the map should
be shown. To always auto-zoom to the full extend doesn't make much sense
if you work in a subset of the area.

> Now it seems
> that's not the problem, instead GRASS isn't even smart enough to draw the
> data at all until i locate some undocumented command to tell it i have a
> monitor.

:-)

> > - in d.m: a menu entry under "display"
> 
> I don't find a "Display All" or "Zoom to Full Extents" command under
> "display".  This is possibly the most common display operation in GIS, and
> it's mysteriously missing.

http://mpa.itc.it/markus/osg05/

> > Sure: how should GRASS know which map you want to see?
> 
> Because it's the map i loaded?  It could at least show me what maps exist so
> that i could indicate which to display?

Then hit the magic button which shows what maps exist.
 
> > >  Command "Display: Redraw active display" opens a blank 
> > > window titled "dialog1" with nothing in it.  And so on.
> > > I get the impression that rather little testing or 
> > > debugging has been done with this application.
> > 
> > We have 1 million hits per month on grass.itc.it
> 
> That's very sad that there are so many people evaluating it when it's so
> broken and far from usable. 

You won't believe it, there are even thousands of *users*...

> Even a tiny amount of testing would turn up
> broken things like that empty "dialog1".
> 
> > Did you consider to read documentation?
> 
> If it existed, i'd love to read it.  The "GRASS GIS 6.0.0 Reference Manual"
> is actually only a reference guide to the backend, low-level command-line
> programming aspect of the program.  I have not found any documentation for
> _the GRASS application itself_.

Well, then I cannot help much.

> >  http://grass.itc.it/gdp/books.php
> 
> As mentioned in another email, one (1) page listing the menu items with a
> screenshot is like no documentation at all.

Here are some more slides:

http://mpa.itc.it/markus/osg05/
Slides (English): OSG'05 GRASS Workshop slides (3.4MB PDF)

Enjoy pages 15 to 18.

> >  http://grass.itc.it/download/addons.php
> >  -> Qt/GRASS
> >  -> QGIS & GRASS
> >  -> JAVAGRASS
> 
> Those are APIs for programmers. 

This indicates that you only looked at the first link.

> I'm talking about an actual GIS application
> intended for use by GIS users.  Isn't anyone considering that?

Yes, many of us. And thousands are already using it.
Maybe I am missing the point here.


Markus

> -Ben
>