Welcome to the GALEX Map. This is a sky browsing and downloading tool for GALEX data organized by sky "tiles." The Map is generated in the open source MapServer development environment as back-end and OpenLayers UI as front-end (the client side). The application has been constructed by GALEX team member Antonio Volpicelli of the Observatory of Turin. We invite comments both on functionality and performance.

The Map has been tested so far with the major browsers ( see table below ) . It is possible that it does not yet work optimally for certain browser/platforms. For example if one is using another window of the browser with a resource hogging application (e.g. tuning into a webcast).

Users may manipulate the Map display in one of two browser planes. Both of these serve as entry points for downloading of data or images of particular tiles. Clicking on the "Images" button will take the user from the tile to the image plane. In doing so, the user will notice a tool tip that advises of the opening of the image tile page, the magnification level at which one enters the new page and, via "Learn More," can take one to the Image Projection section on this help page.

TILE PROJECTION:

This plane allows one to navigate quickly to an interesting sky region. These are based on a Mollweide (cylindrical projection of the sky onto an elliptical shape on the screen) and Mercator (rectangular) projections. We call our Mollweide projection, the entry point of the tool, the "tile plane" because it shows tiles as squares denoting the positions of various GALEX GR3 survey observations. These squares are deformed at high declinations.

IMAGE PROJECTION

We refer to the Mercator projection also as the "image plane" because it enables browsing of the GALEX sky image in NUV bandpass. One brings up the image plane by clicking on the "Images" button above the Mollweide projection.

 

 

IMAGE PROJECTION

We refer to the Mercator projection also as the "image plane" because it enables browsing of the GALEX sky image in NUV bandpass. One brings up the image plane by clicking on the "Images" button above the Mollweide projection.

THREE MODE ICON CONTROLS

Many of the functionalities of the Map are controlled by Icons in the lower right and are listed as follows: Controls affect the display or behavior of the map. Note that clicking on any of the first three icon initiates a particular operating mode. This mode continues to function until an alternate mode is activated by clicking on one of other two icons. Hence only one these three icons is active at a time. When the mode is active, the icon button turns bright. Note that the Globe button follows the 3 icon/mode buttons, but it does not work quite the same way: clicking the Globe button enables its functionality (repositioning the entire tile sky on the screen) but retains the functionality of the still active icon.

PANNING (DRAGGING)

The most common operating mode is panning (dragging) across the sky plane (enabled when the map start). This works on either the tile or image planes. Panning can be initiated in any of three ways. The first is to click on the Hand on the icon menu. (Note again that the Hand and other icons do not 'toggle' on and off.)
Second, panning can be initiated by clicking on any of the four compass arrows above the zoom bar. This action is independent of (but equivalent to) invoking panning by clicking Pan icon. To move the sky up (tiles or images down) click on the up compass arrow. Note that as the user pans, new images will be reloaded into the client computer. For the third way of panning, consult the OVERVIEW section below. A special (if redundant) note: If one has many surveys like the AIS survey clicked on (see LAYER SWITCH, also below), image loading can be a time consuming process. For this reason we recommend that a user click on the mininum number of surveys he/she plans to work with and restrict oneself to a fairly small region of the sky before turning on the image plane.

RUBBER BAND (ZOOM) BOX

The user may control the region of the sky on the screen by clicking the rubber band icon with the cursor. The first click enables the drawing of a rectangle. Moving to a new posiiton defines the diagonal with respect to the first clicked point and hence the extent of the rectangle. After the second click, the tile plane redraws on an expanded region defined by the rectangle just drawn. Tip: it's a common mistake to forget after this action that the rubber band mode is still active. Be sure to click on the Hand or Info icon to get into a new operating mode.

INFORMATION ON TILES (DOWNLOADING):

To initiate the data product inspection and download process, the user clicks on this Information button in the icon menu. Once this mode is activated. This will return an active Table page listing all tiles centered within one degree of the designated sky position, sorted by that position. The first two columns can be selected either to inspect the tile's image up close or to take us to a list of grouped data products, such as "Minimum Recommended Rroducts." Clicking on a tile entry takes one to a listing of these products, and one can check some or all boxes to download files of interest. (This is a similar route that GALEX users take to access to these data from the Survey pages.)

ZOOMING

GLOBE

SCREEN CENTER MARKING

One may place/delete a red cross symbol on the tile plane by clicking/unclicking on the red cross button. This will keep track of the position of the center of the screen's screen when he pans and zooms around. This symbol is useful to help prevent getting lost, particularly if one comes to a new small sky region after zooming in without recentering.

OVERVIEW

A nice feature of the Map is that one can retain a postage stamp image of the full sky to see what subregion the tile plane is showing. This allows one additional navigational control. Clicking on the in the lower left of the tile screen will show the subregion of the sky displayed in the tile plane. This shows the region of the sky the user sees on his/her screen. Notice that by moving the cursor on the red rectangle across the small image of the whole sky, one can move the region represented on the main plane. This is a third way of panning across the sky to a new position.

LAYER SWITCH

Clicking on the symbol in the top right (next to the "Legend" ) depicts all the possible surveys ("layers" in Mapserver parlance). The Base Layer defines the Map and its bounds, the Overlay Layers are superimposed to the base. The user is free to check or uncheck any of them anytime. Depending on whether a survey is clicked or not, this operation shows or hides the various surveys. In general, it is most convenient to designate only those surveys that the user expects to browse - again, this action can be revised anytime during the session.

LEGEND

Notice in the upper right of the tile screen a series of tabs and a box containing more information - so far only "Legend" and "Search" is represented.

The Legend is a color-coded list of the various GR surveys. To the left of the Legend is a + symbol. Clicking on this symbol will allow one to immediately turn on or off the tile symbols for the various surveys. To get familiarized with the Map's features, we suggest clicking off the AIS (All Sky imaging Survey: deep blue). This will minimize confusion and speed up loading of images into your computer. Note also the presence of the grism surveys (DSS, MSS,WSS). These are actually the direct-image pictures of the tiles observed by the grism. (Howver, to download grism data, one can click on the Information icon and then on a *SS survey of interest to download grism fits data.

SEARCH BOX

The Search button at the top allows input of a set of coordinates or an object name. The tile page will then recenter to this requested position. Note that this request results in an automatic zooming to the maximum level.

Type the name or coordinates of an object of interest into the "search box" and click on "search". If an object name is used, the request is sent to the name resolver at NED, which returns the coordinates. Some examples might be: