[Mapserver-users] Question/Bug on CGI/Template Interface

Tue Dec 23 10:23:18 EST 2003

Hi Steve: I think I'd classify this as both a bug and a mis-application.
As I read the template I see that you're essentially telling MapServer 2
ways to generate an image in the same form- from a mouse click and from
a point/scale. That's likely confusing things. There is an order of
precedence in place, but that addresses using an image zoom box vs a
point zoom. The order of arguments could also be having an impact. I've
tried to minimize confilcts like this but to a certain extent it's
unavoidable. Perhaps setting a 'no scale' value where scale is ignored
would help (that's the bug) but I'd have to check the source.

To fix? Well, if you can use javascript it's easy. I'd rename the
control for setting scale to something else (so as not to confuse the
CGI and have it call a small function to regenerate the interface at the
right point. You'd move the substitutions for [mapx] and [mapx] into
that function instead of hidden variables.

If you can't use javascript then you'd be best of having 2 forms. One
for the main pan/zoom and another for the scale-based zoom.

Steve

>>> <woodbri at swoodbridge.com> 12/23/2003 12:16:37 AM >>>
Hi all,

I have run into an interesting problem. I would like to be able to 
have some fixed zoom scales so I built the template below. You will 
notice that in the <INPUT NAME="img1" ..> tag I named the image 
"img1" this is because if I name it "img" I get the following error:

msCalculateScale(): General error message. Invalid image extent. 
msCalculateScale(): General error message. Invalid image extent. 

BUT, if I add the <input type=hidden name=IMGEXT ...> then the zoom 
to scale does not work. But without the "img" tag I can't pan the 
map.

So is this a bug, A miss-application, Or what?

I would like to be able to pan and zoom, but also be able to force 
the map to a specific scale. What am I missing here?

Thanks,
  -Steve W.

------------------------------ main template file -------------------
<html>
<head><title>MapServer Demo Interface</title></head>
<body bgcolor=#FFFFFF>

<center><h1>MapServer Demo Interface</h1></center>
<hr>
<form method=GET action="/cgi-bin/mapserv">

<center>
<table border=0 cellspacing=0 cellpadding=4 bgcolor="#000000">
<tr>
<td valign="top" align=center>
  <table cellpadding="0" cellspacing="0" border="0">
    <tr>
      <td colspan="2">
        <INPUT NAME="img1" TYPE="image" SRC="[img]" width=[mapwidth] 
height=[mapheight] border=0>
      </td>
    </tr>
    <tr>
      <td>&nbsp;<font size=-1 face="arial,helvetica" 
color="#FFFFFF"><b>Powered by MapServer</b></font></td>
      <td align="right"><img src="[scalebar]"></td>
    </tr>
  </table>
</td>
<td valign="top" bgcolor=#ffffff>
  <table cellpadding="5" cellspacing="0" border="0" 
bgcolor="#ffffff">
    <tr><td>
      <center><input type="submit" value="Refresh/Query"></center>
      <p>

      <input type="radio" name="mode" value="browse" checked> 
<b>Browse map</b><br>
      <input type="radio" name="mode" value="query"> <b>Query 
feature</b><br>
      <input type="radio" name="mode" value="nquery"> <b>Query 
multiple features</b>

      <hr>
      <p>
      <input type="radio" name="scale" value="20000000"> Scale 
1:20M<br>
      <input type="radio" name="scale" value="4000000"> Scale 
1:4M<br>
      <input type="radio" name="scale" value="1000000"> Scale 
1:1M<br>
      <input type="radio" name="scale" value="500000"> Scale 
1:500K<br>
      <input type="radio" name="scale" value="150000"> Scale 
1:150K<br>
      <input type="radio" name="scale" value="50000"> Scale 1:50K<br>
      <input type="radio" name="scale" value="25000"> Scale 1:25K<br>
      <input type="radio" name="scale" value="15000"> Scale 1:15K<br>
      <input type="radio" name="scale" value="10000"> Scale 1:10K<br>
      <input type="radio" name="scale" value="7500"> Scale 1:7500<br>
      <input type="radio" name="scale" value="5000"> Scale 1:5000<br>
      <input type="radio" name="scale" value="2000"> Scale 1:2000<br>

    </td></tr></table>

  </td></tr>
</table>
</center>

<input type="hidden" name="mapxy"                value="[mapx] 
[mapy]">
<input1 type="hidden" name="imgxy"                value="299.5 
299.5">
<input1 type="hidden" name="imgext"               value="[mapext]">
<input type="hidden" name="map"                  value="[map]">
<input type="hidden" name="map_web_template"     
value="[map_web_template]">
<input type="hidden" name="map_size"             value="[map_size]">
<input type="hidden" name="map_legend_status"    value=off>
<input type="hidden" name="map_scalebar_status"  value=on>
<input1 type="hidden" name="savequery"            value="true">
<input1 type="hidden" name="mapext"               value="shapes">

</form>

<p><hr><p>
Scale 1:[scale]
</body></html>

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