Handling apostrophes in field names and class expressions
Pagurek,Debbie [NCR]
Debbie.Pagurek at EC.GC.CA
Mon Oct 24 13:14:25 EDT 2005
CLASSITEM "type_de_cours_d__eau_échantillonné"
CLASS
NAME "Cours d'eau"
EXPRESSION /Cours d\'eau/
COLOR 0 151 0
SYMBOL "circle"
SIZE 5
END
Found a solution to part of my problem. Regex helps when dealing with a class expression that contains an apostrophe.
I've been trying to deal with the French part of our app, and one of the issues is having meaningful field
Names when the user queries in Chameleon. SQL Server / OVF let's you write stuff like:
select typ as "type_de_cours_d'eau_échantillonné". Mapserver won't let you use this
for a classitem. It will if you use %27 for the apostrophe, but then Chameleon query widget doesn't like it. But it's probably not good practice to have apostrophes in field names, so we will have to do a search and replace in our chameleon query widget (2 underscores = ', 1 underscore = space).
The other problem was that I needed to classify on something that had an apostrophe in it (e.g. the words
"cours d'eau" are in the database). Mapserver doesn't like that in a string expression, but I found
out that regex works:
EXPRESSION /cours d\'eau/
So - some more solutions to the difficulties I was having. I just didn't know where my problems were
occuring - in the OVF, in Mapserver, or in Chameleon. Turned out to be a bit of SQL Server (it really
shouldn't let you put quotes into a field name, postgresql doesn't) and handling everything in
Mapserver and chameleon.
Hope this helps someone else.
D. Pagurek
-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Pagurek,Debbie [NCR]
Sent: Friday, October 21, 2005 5:11 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] Handling apostrophes in field names and class expressions
Hi all,
I'm experiencing some difficulties with a mapfile that I'm using that has apostrophes in fieldnames and also apostrophes in class expressions.
Funny - I thought my problems would all happen because of the French characters, but that doesn't appear to be the problem.
For instance - can someone confirm that a CLASS Expression "Cours d'eau" will work?
Mapserver 4.6.1, Windows.
Can anyone comment on what Mapserver does with encoding?
D. Pagurek
-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Frank Warmerdam
Sent: Friday, October 21, 2005 4:16 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] RFC 5 - Horizon clipping during reprojection
On 10/21/05, Bruce Raup <brauplists at gmail.com> wrote:
> Hi Frank,
>
> RFC-5 was just today called to my attention. I think it's great that
> this is being (has been) addressed. Two closely related issues (I
> think) are these:
>
> A. How are polygon vertices joined? 1) By straight lines in the
> projection, or 2) as great-circle arcs? Can this be specified in the
> mapfile? If not, it would be great to have a LAYER-level parameter,
> something like JOINVERTICES=greatcircle or JOINVERTICES=straightline.
> The GMT program "psxy" offers such a choice (the -A option).
Bruce,
Currently a straight line in the output projection is created between the point at which the polygon boundary went "over the edge", and where it came back. This does result in anomolies as we can see a bit in the sample images I provided.
The reason something smarter (like great circles or some other way to track the horizon) wasn't done was limited time. The client decided they didn't want to fund that degree of fidelity unless they find the current approach unsatisfactory.
> B. When making a selection in the mapserver viewport (via jbox, for
> example), only the corner coordinates of that box get converted back
> to the coordinate system of the data, which means that what is
> selected can be very different from what you see. I wrote about this
> before. See http://spot.colorado.edu/~braup/MapServer/ for an example
> of polar weirdness. Has this issue made it to the bug list? I can do
> that if you guide me on how.
I am aware of this problem, but there has been no effort (other than a bit of thinking) to resolve it. I'm not sure if there is a bug report on this issue or not. You can find info at the following url on how to submit bugs.
http://ms.gis.umn.edu/development/bugs/
The case of reprojecting bounding boxes is handled specially via the
msProjectRect() (in mapproject.c) and this function already has lots of logic about sampling along edges, and through the rect if some points fail to reproject. But it does not have any logic to deal with special polar issues. If we could force it to use the internal sampling for such cases that would help though not completely resolve the issue.
I have included the code in case you would like to skim it and consider possible fixes.
There is a wiki area for discussion of "world mapping problems" where I liked to accumulate such issues, but with the wiki locked down now there isn't an easy place to catalog such things.
Best regards,
--
---------------------------------------+--------------------------------
---------------------------------------+------
I set the clouds in motion - turn up | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
ack. This does result in anomolies as we can see a bit in the sample images I provided.
The reason something smarter (like great circles or some other way to track the horizon) wasn't done was limited time. The client decided they didn't want to fund that degree of fidelity unless they find the current approach unsatisfactory.
> B. When making a selection in the mapserver viewport (via jbox, for
> example), only the corner coordinates of that box get converted back
> to the coordinate system of the data, which means that what is
> selected can be very different from what you see. I wrote about this
> before. See http://spot.colorado.edu/~braup/MapServer/ for an example
> of polar weirdness. Has this issue made it to the bug list? I can do
> that if you guide me on how.
I am aware of this problem, but there has been no effort (other than a bit of thinking) to resolve it. I'm not sure if there is a bug report on this issue or not. You can find info at the following url on how to submit bugs.
http://ms.gis.umn.edu/development/bugs/
The case of reprojecting bounding boxes is handled specially via the
msProjectRect() (in mapproject.c) and this function already has lots of logic about sampling along edges, and through the rect if some points fail to reproject. But it does not have any logic to deal with special polar issues. If we could force it to use the internal sampling for such cases that would help though not completely resolve the issue.
Best regards,
--
---------------------------------------+--------------------------------
---------------------------------------+------
I set the clouds in motion - turn up | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
/***********************************************************************
*/
/* msProjectGrowRect()
*/
/***********************************************************************
*/
#ifdef USE_PROJ
static void msProjectGrowRect(projectionObj *in, projectionObj *out,
rectObj *prj_rect, int *rect_initialized,
pointObj *prj_point, int *failure )
{
if( msProjectPoint(in, out, prj_point) == MS_SUCCESS )
{
if( *rect_initialized )
{
prj_rect->miny = MS_MIN(prj_rect->miny, prj_point->y);
prj_rect->maxy = MS_MAX(prj_rect->maxy, prj_point->y);
prj_rect->minx = MS_MIN(prj_rect->minx, prj_point->x);
prj_rect->maxx = MS_MAX(prj_rect->maxx, prj_point->x);
}
else
{
prj_rect->minx = prj_rect->maxx = prj_point->x;
prj_rect->miny = prj_rect->maxy = prj_point->y;
*rect_initialized = MS_TRUE;
}
}
else
(*failure)++;
}
#endif /* def USE_PROJ */
/***********************************************************************
*/
/* msProjectRect()
*/
/***********************************************************************
*/
#define NUMBER_OF_SAMPLE_POINTS 100
int msProjectRect(projectionObj *in, projectionObj *out, rectObj *rect) { #ifdef USE_PROJ
pointObj prj_point;
rectObj prj_rect;
int rect_initialized = MS_FALSE, failure=0;
double dx, dy;
double x, y;
dx = (rect->maxx - rect->minx)/NUMBER_OF_SAMPLE_POINTS;
dy = (rect->maxy - rect->miny)/NUMBER_OF_SAMPLE_POINTS;
/* first ensure the top left corner is processed, even if the rect
turns out to be degenerate. */
prj_point.x = rect->minx;
prj_point.y = rect->miny;
#ifdef USE_POINT_Z_M
prj_point.z = 0.0;
prj_point.m = 0.0;
#endif /* USE_POINT_Z_M */
msProjectGrowRect(in,out,&prj_rect,&rect_initialized,&prj_point,
&failure);
/* sample along top and bottom */
if(dx > 0) {
for(x=rect->minx; x<=rect->maxx; x+=dx) {
prj_point.x = x;
prj_point.y = rect->miny;
msProjectGrowRect(in,out,&prj_rect,&rect_initialized,&prj_point,
&failure);
prj_point.x = x;
prj_point.y = rect->maxy;
msProjectGrowRect(in,out,&prj_rect,&rect_initialized,&prj_point,
&failure);
}
}
/* sample along left and right */
if(dy > 0) {
for(y=rect->miny; y<=rect->maxy; y+=dy) {
prj_point.y = y;
prj_point.x = rect->minx;
msProjectGrowRect(in,out,&prj_rect,&rect_initialized,&prj_point,
&failure);
prj_point.x = rect->maxx;
prj_point.y = y;
msProjectGrowRect(in,out,&prj_rect,&rect_initialized,&prj_point,
&failure);
}
}
/*
** If there have been any failures around the edges, then we had better
** try and fill in the interior to get a close bounds.
*/
if( failure > 0 )
{
failure = 0;
for(x=rect->minx + dx; x<=rect->maxx; x+=dx) {
for(y=rect->miny + dy; y<=rect->maxy; y+=dy) {
prj_point.x = x;
prj_point.y = y;
msProjectGrowRect(in,out,&prj_rect,&rect_initialized,&prj_point,
&failure);
}
}
if( !rect_initialized )
{
if( out == NULL || out->proj == NULL
|| pj_is_latlong(in->proj) )
{
prj_rect.minx = -180;
prj_rect.maxx = 180;
prj_rect.miny = -90;
prj_rect.maxy = 90;
}
else
{
prj_rect.minx = -22000000;
prj_rect.maxx = 22000000;
prj_rect.miny = -11000000;
prj_rect.maxy = 11000000;
}
msDebug( "msProjectRect(): all points failed to reproject, trying to fall back to using world bounds ... hope this helps.\n" );
}
else
{
msDebug( "msProjectRect(): some points failed to reproject, doing internal sampling.\n" );
}
}
rect->minx = prj_rect.minx;
rect->miny = prj_rect.miny;
rect->maxx = prj_rect.maxx;
rect->maxy = prj_rect.maxy;
if( !rect_initialized )
return MS_FAILURE;
else
return(MS_SUCCESS);
#else
msSetError(MS_PROJERR, "Projection support is not available.", "msProjectRect()");
return(MS_FAILURE);
#endif
}
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