Mapdex Webservice Guide

• Overview
• Request
• Response
• Access Methods
• Query Samples

Overview

The Webservice allows you to search the Mapdex database for

• servers
• services
• layers
• columns
• a combination of the above queries
• layers showing a given latitude-longitude envelope(or a part of it)

webservice url: http://www.mapdex.org/search/MapdexToolbar/mapdexsearch.cfm

Request

Search parameters

Example

servers=usgs or noaa
service=
layer=road or street
column=address or label or name
operator=and

translates to...

search all layers with,
(server name containing usgs or noaa) and
(layer name containing road or street) and
(column name containing address or label or name)

Limitations

• The parameters are case-insensitive. However, sorting of results is case-sensititve.
• One of the server, service, layer, column or envelope keywords is mandatory for the request to succeed. However, envelope alone queries(without layer keywords) should be avoided as they tend to be exhaustive.
• Envelope queries have to and can only be accompanied with layer keywords(provided through the 'layer' parameter). However, the results may be sorted based on server names, service names, layer names or projection type.
• For 'server' queries, the response will not include xml attributes specific to layer description(layer name, layer id, minscale, maxscale etc.,) unless otherwise you also provide a value for the 'sort' parameter other than 'svr'. This is because the server queries are exhaustive.

Response

The response for the queries is in XML format. The name of the root node in the XML data is 'mapdex'. The result node is 'response' and the error node is 'error'.

Response for a successful query:

• the root node(<mapdex>) has attributes that restate the request.
• the <header> node provides quantitative information about the response.
• the actual results will be in separate <response> nodes.

<?xml version="1.0" encoding="UTF-8"?>
<mapdex servers="" service="" layer="" column="" envelope="" operator="" type="" srt="" odr="" alpha="">
	<header requested="" returned="" from="" to="" total="" hasmore=""/>
	<response attr1="val1" attr2="val2"... />
	...
	...
	<response attr1="val1" attr2="val2"... />
</mapdex>
		

Response for a failed query:

• the root node(<mapdex>) has no attributes.
• <header> node is not applicable for error responses.
• the <error> node has a <message> child and occasionally <type>, <detail> and/or <database>

<?xml version="1.0" encoding="UTF-8"?>
<mapdex>
	<error>
		<type>...</type>
		<message>...</message>
		<detail>...</detail>
		<database>
			<sql>...</sql>
			<query>...</query>
		</database>
	</error>
</mapdex>
		

<mapdex> attributes

The <mapdex> element restates the search query.

• servers - server keywords
• service - service keywords
• layer - layer keywords
• column - column keywords
• envelope - lat-long envelope
• operator - boolean operator for combinational queries
• type - type of query processed
• srt - sort field
• odr - sort order
• alpha - alphanumeric character, if any, provided
• needurl - whether the user requested for server and service info urls or not

<header> attributes

• requested - number of results requested per query
• returned - number of results actually returned in this query
• from - the index of the first result in the query
• to - the index of the last result in the query
• total - total number of matches for the query in the database.
• hasmore - YES: if there are more records, NO: if there are no more records.

<response> attributes

Each <response> node corresponds to a record in the database that matched the query.

• server - the name of the server
• ip - the IP address of the server
• serverinfourl - web location where you can find the information about the server such as services hosted in it
• service - the name of the service
• projection - the type of projection set for this service
• serviceinfourl - web location where you can find the information about the service such as layers, environment, properties etc.
• layername - the name of the layer
• layerid - the layer ID
• featureid - the feature ID
• minscale - the minimum possible scale for the layer
• maxscale - the maximum possible scale for the layer
• minx, maxx, miny, maxy - envelope extremes
• columncount - the number of columns in the layer that matched the given column keywords [for column search only]
• env_diff - a rough calculation of the extent of area covered by the envelope. Mathematically, it is equal to (maxx-minx)+(maxy-miny) [for envelope search only]

How to access the webservice?

Simple method

A url is called with the required parameters submitted through either GET or POST. The base url is:
http://www.mapdex.org/search/MapdexToolbar/mapdexsearch.cfm

Sample query string to be used for GET method is:
?servers=usgs+or+noaa&service=&layer=road+or+street&column=address+or+label+or+name&operator=and

Notice that 'usgs or noaa' is represented as usgs+or+noaa i.e '+' is substitued for space.
The querystring is appended to the base url to obtain the complete url for query.

Query Samples