SVOCat Documentation

Version 2.01, October 2020, author: Carlos Rodrigo

1. Introduction
2. Download
    2.1. Extract
    2.2. Permissions
3. The files
4. Example
5. Configure
    5.1. First
    5.2. Project
    5.3. Mysql
    5.4. Web
    5.5. VO options
    5.6. Fields
    5.7. Photometry
    5.8. Search Opts.
    5.9. File Paths
    5.10. Scripts
    5.11. Registry
    5.12. Spectra
    5.13. Links
    5.14. References
6. Web Design
    6.1. style.css
    6.2. Colors
    6.3. header.php
    6.4. footer.php
7. Extra tips
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[First][Project][Mysql][Web][VO options][Fields][Photometry][Search Opts.][File Paths][Scripts][Registry][Spectra][Links][References]

Search Options

By default the 'Data Retrieval' section of the web page will include a simple Cone Search form where users can search for catalogue entries around a given point in the sky (RA and DEC) and within a search radius (SR).

But you have the option to configure your service so that users can restrict searches using other catalogue fields.

For each field (except RA and DEC, that are always required) you can set the 'Search' column to "Yes" and it will be optionally allowed for searches.

If you mark a field as "Yes", you must also set the "Search type" and "Form Type" to specify how this field should be used.

  • 'Search Type' can have three different values:
    • 'Value': the user will be allowed to specify only a value for this field. In this case, only results matching the given value will be displayed. For numeric type fields this means that the value is exactly the same. For string fields, the search will be done in a SQL " 'value'..." way, what means that "%" can be used as wildcard.
    • 'Range': the user can specify a range of values. Queries will be restricted to results so that the field value is in the range. A open range (for instance, leaving the maximum blank) will be understood as no boundary.
    • 'List': the user can specify a list of desired values separated by commas.
  • 'Form type' can have two different values:
    • 'input': a open field will be shown to the user so that he/she can write a free value.
    • 'select': a select box will be shown to the user with all the available values in the database for this field.

You must set this configuration values wisely. For instance:

  • It does not make sense to set 'Search type'='range' for string fields.
  • It is usually better to set 'Search type'='range' for double fields (they often contain an unspecified number of decimals and it's difficult for the user to match an exact value).
  • It only makes sense to set 'Form type'='Select' if the list of different values for that field (in the whole catalogue) is short. For instance, if you have a catalogue column specifying the object type as "star, galaxy, probably star, probably galaxy, unknown" it is ok. But it does not make much sense offering a select box with hundreds or thousands of values in it.

In our case we have allowed to restrict searches using the spectral type. Now the search form will show the corresponding entry for this field and users can restrict the results to those with a particular spectral type, for instance, L1.5 (just an example)::

you can see that the list of results has changed. Now there are only 3 objects objects with this spectral type.

Mags/Colors search

In the case that your catalogue contains photometry values, an special form can be included to search for magnitude and colors ranges.

Object Name/Target search

In the case that your catalogue contains astronomical objects you could want to configure special options to allow for alternative object names using Simbad information.

Default search

When a user first accesses the 'Data retrieval' section it is usual to show, at least, a part of the catalogue by default. This means performing a "Default search" and showing the results of this search.

You can configure here if you want to show the catalogue as default, how many results you want to show and if you want to add some restrictions to the default search.

In our example catalogue, that is very small, we have chosen to show all the results sorted by the object name (oby=name).

But you can include more restrictions. For instance, you can ask to show only entries with L8 spectral type:

and the default result would include that restriction:

Other search options

In this section you can allow to make searches without using RA,DEC coordinates. This is necessary for catalogues that do not contain RA,DEC and is also useful for catalogues where you expect that the most interesting queries will be made in terms of other columns.

Special listings

In the search page you can specify some special listings for catalogue entries with certain properties. These will appear as links so that, when the user clicks on of them, a search will be done and the corresponding results will be shown. To do this you must specify the text that will appear highlighted and the restrictions in terms of the database fields (only for database fields that have been configured above as available for search, that is, in this case, the spectral type (opspty).

In our example catalogue this does not make much sense because it is very small. But we could, for instance, define a link as:

That, if clicked, would produce a list of objects with spectral type = L8.

Search options in ConeSearch

Although the VO ConeSearch protocol only specifies that RA/DEC/SR must be the search criteria, it does not forbid to restrict searches using other catalogue fields.

In our particular implementation of ConeSearch all the search restrictions that are allowed for the web page are also allowed for the ConeSearch queries.

In order to make these options public, we have implemented a 'format=metadata' option in the same way as it is specified in the SSA protocol:

(where, remember, should be the main URL that corresponds to your installation)

There, among other things, the list of parameters allowed for queries are specified in the usual fashion (and the available range or list of possible values when appropriate).

so that valid queries to the catalogue ConeSearch service could be, for instance:


depending on how the user wants to restrict the query.

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