Zooming and Centering Question: Second Run

[Bob Bruce]

Giridhar:
            I have never used zoompoint but, by my reading of the PHP
documentation, you can use it to zoom by a factor of the current scale
instead of specifying an actual scale. Other than that, the arguments are
identical.

    Bob

On Sat, 30 Apr 2005 02:51:51 -0400, Giridhar Manepalli <gmanepal at GMAIL.COM>
wrote:

>Thanks Bob! It really helped. Can you tell me how zoomscale and
>zoompoint are different from a map point of view.
>
>Giridhar
>
>On 4/25/05, Bob Bruce <covariance at shaw.ca> wrote:
>> On Sun, 24 Apr 2005 23:01:06 -0400, Giridhar Manepalli <gmanepal at GMAIL.COM>
>> wrote:
>>
>> >Hello All,
>> >I am using php mapscript. I cannot get the image to center when I
>> >click on the image and with some zooming factor.
>> >
>> >I am using image coordinates (not geographical coordinates) for zooming.
>> >
>> >1.)Can anyone think of possible reasons? I can provide with any
>> >necessary information.
>> >
>> >2.) Also, how do I center the image based on my click without zooming?
>> >
>> >3.) Finally, does the extent of the map automatically changed by
>> >mapscript, when I zoom?
>> >
>> >I hope, i can get this resolved!
>> >
>> >Thanks,
>> >Giridhar
>> >
>> >
>> >Hello All,
>> >I tried to center the image based on a click when I zoom using
>> >php/mapscript. For some reason, I am failing to do so.
>> >
>> >Is it because, the lat long I calculated using javascript is wrong?
>> >but it almost matches with 'ArcIMS Author'.?
>> >
>> >Can anyone write the snippet of php/mapscript code that will zoom to
>> >the point i click, provided I have the lat-long of the click? Also,
>> >can you explain what the new extent will be?
>> >
>> >Thanks,
>> >Giridhar
>>
>> Giridhar:
>>
>> here's a code snippet that I use for zooming in:
>>
>> } elseif($_POST['mode'] == "ZoomInAtPT" ) {
>>          $new_point = ms_newPointObj();
>>
>>
$new_point->setXY(floatval($_POST['mapimage_x']),floatval($_POST['mapimage_y']));
>>          $map->zoomscale($mapscale/$mapScaleZoomFactor, $new_point,
>> $map->width, $map->width,
>>
>> $mapRect, $maxmapRect);
>>
>> the post variables are the image coordinates of the mouse click. You should
>> have those anyway and it shouldn't be necessary to convert them to Lat/Long.
>> I get $mapscale using the statement:
>>
>>      $mapscale = isset($_POST['mapscale']) ? floatval($_POST['mapscale']) :
>> $maxscale;
>>
>> and I set the post value of mapscale using the following statements:
>>
>> // now set up some web page display values
>>      $currentscale = round($map->scale);
>>      $char_scale = number_format($currentscale);
>>
>> and this is my code to re-center the draw:
>>
>>      } elseif($_POST['mode'] == "recenter" ) {
>>          $new_point = ms_newPointObj();
>>
>>
$new_point->setXY(floatval($_POST['mapimage_x']),floatval($_POST['mapimage_y']));
>>          $map->zoomscale($mapscale, $new_point, $map->width, $map->width,
>> $mapRect, $maxmapRect);
>>
>> (notice that I don't change the scale in this call)
>> and this is the code to set the last two values of the above call:
>>
>>      if(isset($_POST['mapextent'])) {
>>          $extents = explode("+",$_POST['mapextent']);
>>          $mapRect = ms_newRectObj();
>>
>>
$mapRect->setextent(floatval($extents[0]),floatval($extents[1]),floatval($extents[2]),floatval($extents[3]));
>>          $maxmapextent = $_POST['maxmapextent']; // save this for the hidden
>> form variable
>>      } else {  // set this for the hidden form variable using the values
>> from the map file
>>          $maxmapextent = $map->extent->minx . "+" . $map->extent->miny . "+"
>> . $map->extent->maxx . "+" . $map->extent->maxy;
>>      }
>>
>>      if(isset($_POST['maxmapextent'])) {
>>         $maxextents = explode("+",$_POST['maxmapextent']);
>>         $maxmapRect = ms_newRectObj();
>>
>>
$maxmapRect->setextent(floatval($maxextents[0]),floatval($maxextents[1]),floatval($maxextents[2]),floatval($maxextents[3]));
>>      }
>>
>> hopefully there is enough here to get you going.
>>
>>      Bob Bruce
>>