Introduction to the EIS WEB Services

30 August 2004


Since the start of the EIS project it has been recognized that maintaining WEB services is of major importance for Public Surveys: serving as a portal to provide:

  1. information about the origin and ongoing developments of the EIS project

  2. list of people, survey proposals and other relevant documentation

  3. information relevant to the surveys and products available

  4. survey data and other products to the community

  5. on-line services (e.g. image cutouts)

  6. a conduit for the user-survey group interaction

Given the inherently dynamical nature of this service and the breadth of information, conventional WEB administration practices requiring long periods of training and repeated interventions, proved to be untenable with the finite resources of the project. Conscious of this short-coming , a long-term, more reliable solution has been pursued. This involved the design, development, implementation, and testing of an infra-structure enabling the maintenance of contents, plots, and tables to be performed automatically. In order to achieve this goal, a major overhaul had to be carried out (requiring the periodic suspension of WEB services) which involved:

Since the information presented in the WEB service is created from well-defined procedures based on data ingested into database tables shared by the survey system, errors are minimized and more easily detected. The navigation has also been greatly simplified, operating mostly in a tree-structure and eliminating nearly all links between branches (surveys). The organization of the pages has also been designed to support a wide variety of survey strategies. The use of XML technology and associated customized style-sheets makes it easier to maintain uniformity of formats and to carry out global changes in the presentation.

Since the WEB services are created and updated automatically, they must follow well-defined procedures. This hands-off operation implies some loss of flexibility in introducing specific features and an economy of words. However, the benefits in terms of content, agility, and ease of maintenance far outweigh this disadvantage.

All automatically generated pages comply with HTML 4.0(1) specifications. We strongly suggest that you use a standard compliant browser and point out that Netscape 4.x, still popular with many UNIX users, does not properly implement HTML 4.

Page Descriptions

This section is meant to outline the different pages and their interconnections in the EIS WEB services. The pages are intended to be self-explanatory and this introduction should serve as an overview of the types of information provided.

EIS Home Page

The EIS Home Page consists of the following sections:

The central element on the EIS Home Page is the table listing all surveys. The information in this table is not only split up by survey name but also by the observing strategies for a survey. For all surveys and strategies, the start and end date of observations, the number of regions and fields (pointings) in these regions are given, as well as the telescope, instrument, and passbands used for the particular observing strategy. The primary aim (galactic/extragalactic) is also indicated.

From this table, links lead to survey specific pages described below.

Survey Pages

For each survey the following pages are available and are described in more detail in the following sections:

If a survey is selected from the main EIS page the user is presented with the Strategy page for that survey and the navigation bar is replaced with one that has links to the survey specific pages and back to the EIS home page.


The Strategy page is split into several sub-pages according to the number of strategies in a survey. By default, the strategy page for deep optical observations is shown first. If a survey has more than one strategy, pages for them are available from a second level navigation bar.

Each strategy page consists of:


This page gives a list of all observing runs for a survey. The Statistics link at the top right leads to a summary of all observations for this survey, split by instruments. Likewise, links to observing run summaries and to period summaries are available from the Observations page.

These summaries present general information about the observations in a chosen time period (survey duration, period or run) such as number of frames, total exposure time, fraction of time spent on source, data volume and data rate, as well as a list of all science targets and standards. All summaries have links down to summaries of a shorter time period (run, night) as well as links to a detailed breakdown of OBs for a given target. Additional statistics about the performance of the observations in the chosen time interval are available from the Statistics button at the top right.


The type of information presented in the Progress page depends on the survey layout in the same way as it does for the strategy page. It is split into several sub-pages according to the number of strategies in a survey. By default, the progress page for deep optical observations is shown first. If a region is covered by more than one field, a DSS cutout with the fields overlayed is presented for each filter. For each field the completeness is specified; fields with completeness $\ge$ 100% are green hatched.

For regions covered by a single field, a table listing the completeness in all passbands is shown.


The Summary page lists the information about exposure time, the number of OBs, the number of frames, the minimun, maximum and median DIMM seeing with which the survey fields were observed for each filter as well as the completeness as shown in the Progress page. If a field is to be observed in more than one filter histograms of the completeness and exposure time are available from the link in the field name column.


The Release page is an overview all data releases of a survey. The link in the left column leads to a page listing all survey products of this release. From there these products can be requested. The README links to a description of the products associated with this release as well as all the information relevant to it.

Non-Survey Pages

A few of the non-survey specific pages are described in the following.

Old Web

This links to the old set of EIS WEB pages. We currently keep this page not only as a reference but also because not all data releases are yet available from the new pages.


This page is very much like the survey specific Observations pages. It gives an overview of all EIS observing runs. The Statistics page in the top right leads to global statistics of the EIS observations. The telescope utilization statistics are based on the rather optimistic assumption that all telescopes are available 365 night/year and 8h/night.

Known Issues

As mentioned in the Introduction, the EIS WEB services continue to evolve and known issues are addressed, fine-tuned and rectified, whenever possible. Some of the issues known to persist are listed below. For problems not listed here user feedback is welcome user feedback. This file will be periodically updated.

About this document ...

Introduction to the EIS WEB Services

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