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How to Draw Icons or Images on a Mapserver Generated Map

Article source: http://www.parsec.it/. Used with author's permission.

In this example I have used the map of the Itasca demo of the Mapserver. I have done only small changes to the map file. The Itasca demo has (into the html file) the parameters of the path where to store the images:

IMAGEPATH "set in index.html" IMAGEURL "set in index.html"

I have changed them as fixed path

IMAGEPATH "/tmp/ms_tmp/" IMAGEURL "/ms_tmp/"

Than I have set as STATUS ON several layers for a better map.

The Database

The positions and the images paths that have to be shown on the map are stored into a table of a database in MySql. I have created a new database named "mapexample" and a new table "weather":

CREATE TABLE weather (

id bigint(20) NOT NULL auto_increment,

imagepath varchar(255) default NULL,

x double(16,4) default NULL,

y double(16,4) default NULL,

PRIMARY KEY (id)

)

and than I have inserted into the table the positions of the weather images and the path of every icon:

INSERT INTO `weather` VALUES (1, '/data/weather/icons/sunny.gif', 478107.0000, 5250301.0000); INSERT INTO `weather` VALUES (2, ''/data/weather/icons/cloudy.gif', 408107.0000, 5220301.0000); INSERT INTO `weather` VALUES (3, ''/data/weather/icons/storm.gif', 468107.0000, 5270301.0000); INSERT INTO `weather` VALUES (4, ''/data/weather/icons/variable.gif', 408107.0000, 5310301.0000);

It is not necessary for the images to be stored into a directory visible from the web, because are taken directly by the script and then merged with the map.

The PHPMapscript code Here is the code I have used for generating the map:


define("img_WIDTH", 0); define("img_HEIGHT", 1); define("img_TYPE", 2);

// CONFIGURATION OF MYSQL ACCESS $MyHost = "localhost"; $MyLogin = "root"; $MyPassword = ""; $MyDatabase = "mapexample";

$mappath = "D:/data/web"; $scale_to_showicons = 1000000; // SCALE LIMIT TO START TO SHOW THE ICONS ON THE MAP

function AddImagesToMap($mapurl) {

global $MyHost, $MyLogin, $MyPassword, $MyDatabase, $scale_to_showicons, $map, $mappath;

// CONNECT TO DATABASE

@mysql_connect($MyHost, $MyLogin, $MyPassword);

@mysql_select_db($MyDatabase);

// IF the scale is small enougth to show the images on the map?

if ($scale_to_showicons > $map->scale) {

// PATH WHERE TO FIND THE MAP IMAGE GENERATED BY MAPSERVER

$mapimagepath = $mappath . $mapurl;

$mapdim = GetImageSize($mapimagepath);

$coords_map_width = $map->extent->maxx - $map->extent->minx;

$mapscale = $mapdim[img_WIDTH] / $coords_map_width;

switch ($mapdim[img_TYPE]) {

case 1:

$mapimg = ImageCreateFromGif($mapimagepath);

break;

case 2:

$mapimg = ImageCreateFromJpeg($mapimagepath);

break;

case 3:

$mapimg = ImageCreateFromPng($mapimagepath);

break;

} ;

$qry .= "select * from weather where x > '" . $map->extent->minx . "' AND x < '" . $map->extent->maxx . "'

AND y > '" . $map->extent->miny . "' AND y < '" . $map->extent->maxy . "'";

$res = mysql_query($qry);

while ($row = mysql_fetch_object($res)) {

$dimic = GetImageSize($row->imagepath);

switch ($dimic[img_TYPE]) {

case 1:

$tmpimg = ImageCreateFromGif($row->imagepath);

break;

case 2:

$tmpimg =?; ImageCreateFromJpeg($row->imagepath);

break;

case 3:

$tmpimg = ImageCreateFromPng($row->imagepath);

break;

}

$x = ($row->x - $map->extent->minx) * $mapscale;

$y = $mapdim[img_HEIGHT] - (($row->y - $map->extent->miny) * $mapscale);

@ImageCopy ($mapimg, $tmpimg, $x, $y, 0, 0, $dimic[img_WIDTH], $dimic[img_HEIGHT]);

} ;

// SAVE THE NEW IMAGE ON THE OLD ONE

switch ($mapdim[img_TYPE]) {

case 1:

ImageGif($mapimg, $mapimagepath);

break;

case 2:

ImageJpeg($mapimg, $mapimagepath);

break;

case 3:

ImagePng($mapimg, $mapimagepath);

break;

}

} ; } ;

$map = ms_newMapObj("itasca.map");

$img = $map->draw(); $url = $img->saveWebImage(); AddImagesToMap($url);

?>

Show Weather On Map

More info: http://www.parsec.it/tutorials/

Roberto Colonello owns and operates http://www.parsec.it and http://www.gmdir.com

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