Contents


GeoPortal Data

Sources:

There are many hundreds of GeoPortal data servers which provide excellent maps and some of which provide orthophotos.  The links below show some of them. There are far more.  

In Europe, first try:

http://www.eurogeoinfo.eu/national-spatial-data-infrastructures

World-wide, try:

http://www.gsdi.org/ElectronicGateways

For a large collection, but not always with live links, try one of the following:

A-F http://geographiccuriosities.freeservers.com/EurLinks1.htm

G-J http://geographiccuriosities.freeservers.com/EurLinks2.htm

I-R http://geographiccuriosities.freeservers.com/EurLinks3.htm

S-Z http://geographiccuriosities.freeservers.com/EurLinks4.htm

Other sources of satellite, aerial images and maps:

Two general sources of satellite and aerial imagery and maps are Google's  Maps and Microsoft's Bing Maps.  The advanced version of Bing Maps is called Bing 3D, (formerly Virtual Earth). They are all in the GeoPortal list and may be used like any other URL in that list.   

Please note that Bing 3D has a box called Bird's Eye which should be opened first.  Uncheck the boxes "show labels" and "show angled view" to obtain a vertical image without road map names. 



When Google Maps is chosen and you zoom in, you will see two buttons:



Click on the "Earth" button to show the aerial view of the terrain.  Uncheck the Labels button to hide road names:



Like Bing 3D this may display as an angled view as well.  Hold the left mouse button down on the lower arrow as shown:



to shift the view to vertical and then click on the N letter to re-centre the image so that north is at the top.

The GeoPortal Data function:

In AirPhotoSE on the main toolbar, click on:



to open the GeoPortal Data page.  The first time, the page will be blank.  The next time the program is run by the current user, it will open at the last used GeoPortal server unless a separate web browser has been spawned.

The main menu of the AirphotoSE GeoPortal page contains 8 items:



File offers a number of functions which are described in detail below.

Crop+Save offers a screen capture method which enables you to make multiple captures easily when you move a displayed GeoPortal map or orthophoto.

GeoPortal opens a dialogue box containing the names of more than 50 useful portals.  You can add more, see below.  

IEWindow controls spawning the Microsoft Internet Explorer web browser for GeoPortals whose web sites contain code which can not be displayed correctly or without error using the internal web browser in AirPhotoSE. When clicked it will offer the entry:



Click to activate it, and a check mark will be shown.



Help displays this help topic.

Mark enables you to write a symbol on the capture layer which can contain numerical values for coordinates displayed by the GeoPortal.

Special Capture is needed when the GeoPortal displays a secondary window containing a map or an orthophoto.

Zoom permits you to zoom into or out of  the displayed GeoPortal image  in fixed steps.  On the toolbar below the menu, a slider offers finer control of the amount of enlargement.  It can be dragged, or with a click on the button, the left and right arrow keys on the numerical keyboard will change this by a small amount.  

Click on GeoPortal to show the list of preset geoportals:



Click on a GeoPortal link on the GeoPortal choice list to highlight it.



Then click OK to open it.  The last GeoPortal opened will be saved and reopened unless you have chosen to spawn the Internet Explorer in a separate window.

Adding new links from stand-alone GeoPortal web sites:

To add a new link, open your Web browser to a desired link perhaps taken from the lists cited above and open it:

Click on the link to give it the focus and save it to the Clipboard.  Make sure you have copied the full name by holding down the Shift key, then pressing End and then Ctrl-C.





Paste the full link name into the Add a GeoPortal Web Link field.  It is necessary to put a short easily identified name in front of the link itself which must always begin with http://. That ensures that the links will be sorted in a meaningful way.



Use the Save button which becomes visible when a change is made in the entry field to  transfer the new link to the list and open it.  If you make a mistake, highlight the faulty link and press the Delete key.  You will be asked if you really want to do this, and if you agree, the link will be eliminated and you can re-enter it.



Click on Yes and the link will be deleted.  All links in the list are saved to a simple asci text file called GeoPortalURLs.txt on the directory where you have installed . AirPhotoSE You can also edit this file with an asci editor like Notepad, but if you make a mistake, the link may be unusable.

Working with the GeoPortal:

When you click on OK, the link will cause the Web browser in AirPhotoSE to display the Web site, or if an Internet Explorer window has been chosen, to spawn IE and display the GeoPortal.  This spawned version of the Internet Explorer must be closed separately.  It is not closed automatically by AirPhotoSE.



The whole Web page will be shown as if you had opened it in a normal Web browser.  

Note:

AirPhotoSE has no control over the appearance of the page or the way you can interact with it.  Each site can only be used in the way the designers of the Web page of the GeoPortal intended.  Although there are a few features which are common to most GeoPortals, nearly all of them differ considerably, so you must learn to use each one separately.



In the example shown here, taken from the Swiss mapping service Web site, you can move seamlessly between an aerial and a map view of any chosen region in Switzerland with a choice of different map backgrounds:



For example, you can show the whole of the country as seen from a great altitude and zoom in or move with the tools provided by the Web site.



On this site, you can display aerial and map detail with scales as large as 1:1000, but most other sites do not offer such high resolution.



Well designed sites offer an option for mixing the aerial and the map view of an area and show grid lines in the coordinate system of the country.  Many other items of interest can also be shown like in a GIS programme.

Warning:

For copyright or other reasons, many GeoPortal sites forbid doing anything except examining an area in their data window.  Consult the terms of use for a site of interest before using any of the options described in the following sections.

To save data to a file for further use in AirPhotoSE, click on Crop + Save on the main GeoPortal menu.  A selection rectangle with inverted colour will appear draped over the middle of the display. It defines the limits of the part of the Web page which can be automatically cropped and saved to a new file.





You can drag, expand or contract this rectangle to exclude Web site features which you don't want to see in the result.  Then with the mouse, hold down the Shift key and click the Right button and you will be presented with a File Save dialogue box which permits you to name the result files in any way desired and to select an output file type as well. Closing this dialogue saves the screen area as selected.  You can then drag the image displayed by the GeoPortal and save with a Right click after each dragging action as many times as you wish to make multiple overlapping images using the same inverted colour rectangular frame.

Each time you click on Crop + Save, the selection rectangle will be shown with the same dimensions and position as it was the first it was displayed and moved. If you wish to save multiple areas, just click the Right mouse button, and the image will be saved with the previously chosen name plus a numerical identifier, e.g. Swiss001., with the number augmented automatically with each right mouse click.  If you prefer, you can use the right click without choosing a file name or type and the files will be saved in Jpeg format starting with 0001.jpg, 0002.jpg etc. However this is ambiguous and unsuitable if more than one location is to be treated. When saving multiple images with incremental numbering, the word Saved and the current number will appear on the menu when the cropped area has been written to disk so that you know that you may continue.  Details of saved cropped areas may be viewed in the Edit window opened from the File menu



If you have copied the coordinates of the mouse cursor (not all Geoportals show this)  to the coordinate search boxes at the top of the GeoPortal window, these will be shown in the Edit window.  They can also be written to the image as described in the topic Calibrating GeoPortal Variants

It may be helpful to use Windows menu keyboard actions to choose a menu item when you want to capture something like coordinates at the mouse position without moving the mouse.  Hold down the Alt key and then press:

F : File menu

S: Crop and Save

G: GeoPortal list

I: Internet Explorer

H: Help or F1

M: Mark the capture with coordinates entered into the coordinate fields above

P:  Special Capture window if enabled as described below

Z:  Zoom

This will allow you to change layers in GeoPortal, and crop a matching area of map and photo precisely in separate files.  The quality of the match between the aerial or satellite image and the map will vary, depending on their relative original scales.  If these differ considerably, then items like buildings or roads may be displaced considerably.

A small number GeoPortal sites open a new secondary browser window to display the site data.  To capture the data from such sites, a separate floating capture window has been added.  The menu bar contains an entry called Special Capture which is activated when a code containing the flag [sc] is inserted in front of the URL name of the site in the selection list. You can insert this code yourself when adding a site that shows capture problems.  For example:

BadenWurttemberg [sc] http://www.geoportal.lv-bw.de/mapbender/



Otherwise the Special Capture menu item is not enabled.

When clicked, a little window pops up with a short menu:



Click on Start Capture to begin the capture process.  

Two temporary hot keys, Ctrl + F10 and Ctrl + F11 are now enabled  Holding down Ctrl  and pressing F10 shows the selection rectangle to be displayed as described above, and this may be moved and re sized.  The information in the rectangle can be saved to a file in the same way as that also described above.  If the site of interest has offered a full screen option, you can also save the full screen using Ctrl and F11.  In some cases, other programmes may be using the Ctrl and F11 combination.  In that case a message will inform you that the capture window will try to use Ctrl and F9.

You can work with the captured area after you have pressed one of the key combinations.



After capturing, you can toggle between a full screen view or the compact initial view by clicking on the Full Screen On/Off menu item.

If you have made a mistake, click the Clear item and then click Start Capture again. 

When you have finished, close the special capture window using the Exit menu item.

If the site starts a new instance of the Internet Explorer to display a detailed area of interest as is the case in the example above, the data to be captured and saved may be displayed and partly hidden behind the secondary browser instance window.  Close this secondary window and move and drag  the selection area to exclude unwanted data, then right click with shift to save to a desired file name or without shift to augment an existing file name with a count as above. 

If you write [ie] after the name you have given to a GeoPortal in the space to the left of the Internet link, the Internet explorer will always be spawned.  In the standard version, the link for the French Geoportáil site and the Java version of the German Bundesamt für Kartographie und Geodäsie sites are always opened in a spawned Internet Explorer window, because the internal web browser of AirPhotoSE can not control their features properly.

Saving the data:

When you have finished, click on Exit to AirPhotoSE and your cropped and saved images will be displayed in separate AirPhotoSE windows unless you have spawned the Internet Explorer in a separate window.  In this case you can use the Snipping Tool which is built into Microsoft Windows Vista, 7, 8 and later versions to make a screen capture, or somewhat more conveniently, you can use a stand-alone tool like Snagit for this purpose.  The files created must be loaded manually for further use.  If you use the Snipping Tool 



and want to save the values of displayed coordinates in the tool output, it is convenient to create a keyboard shortcut so that mouse coordinates are not changed.  



Stitching multiple images with the Microsoft Image Compositing Editor (ICE)

For saving multiple images, it is usually best to move the Web page image with the portal's "drag" function, usually the left mouse key held down after perhaps clicking on a hand button rather than moving the selection window which retains it's size, shape and position for multiple crops and saves. If the multiple windows are to be stitched together to form a larger image, this makes it easier to judge the extent of the required overlap between images so that the stitching programme can match features in the overlap area easily.  The overlap should be at least 10% of the image width.  In areas with few features or with maps that have sparse thin lines, up to 25% may be necessary.

Many GeoPortal sites also offer the option of moving the viewer window in the image database by a fixed amount either left or right or up or down by clicking on small arrows on the borders of the viewer window. This makes it easy to keep multiple images aligned.

If calibration of the result is desired, and if the GeoPortal offers a search option using numerical coordinates in a local grid or in UTM, then it is helpful to move in fixed distance steps to the east or west and north or south such that the saved image tiles overlap.  Some GeoPortal sites place a marker at the centre of the image after moving.  The coordinates entered in the search option can usually be saved to the Clipboard and pasted into Notepad running at the same time to create a list of centre coordinates for each tile.  These may then be used as calibration points.

Busy GeoPortal sites sometimes fail to react during a long session when saving multiple images and the operation must be completed at a later time when the site isn't busy.  The GeoPortal code in AirPhotoSE records the file name of each image tile created in a list which is written to disk when the GeoPortal window is closed and reloaded from disk when it is opened later.  The File menu:

 

offers the option for clearing this list and deleting the small disk file which contains the tile image file names.  It also offers an option for running the free image stitching programme Microsoft ICE when a set of image tiles has been created using the list of file names.  These are opened automatically in ICE when it starts up.

Multiple images may be stitched together using many image stitching programmes, but the Microsoft Image Compositing Editor (ICE) is recommended for it's ease of use and ability to make very large files. It also provides for the stitching of plane images which is needed in this application.  It can be downloaded and installed without charge from:

Microsoft Research


Install ICE before running AirPhotoSE.  See the Installation Notes for details.

If it is installed, and you have saved two or more images, the Run ICE entry on the file menu becomes visible. When clicked, the names of the saved images or the sequence names described above are passed directly to ICE which then stitches them into a larger image.  The list of saved names can be added to if you have missed an area and the operation repeated. The number of currently saved images which can be passed to ICE is shown next to the Saved entry on the main menu.  When you choose Exit to AirPhotoSE or Quit, the list of names is not cleared so that you can add more tiles to a previously created set.  The tile name list is called "GeoPortalFiles.txt" and it is always written to the directory on which the tiles reside.  If you change the working directory and open GeoPortal again, you can create new tile lists without overwriting an extant list.

Note:

Each list refers to a set of image tiles from a chosen location.  If you change this location by a large amount, the data will be ambiguous and stitching will fail.  Hence, take care to clear the list before starting a new tiling operation in another area or create the new tiles on a different directory.

The File Menu



When an image list is loaded, more options appear on the file menu.  You can clear the list to start over again, load an existing list which you have saved with save image list or edit the image list. When you click Edit, a window pops up showing the full file name of each image, and if saved, the geographic coordinates of it's centre in the grid system chosen in Options.  The images are passed to ICE in the order shown in the list.  You can change the order of the images passed to ICE by highlighting an image name on the list with a mouse click or with the up and down arrow keys on the numerical keypad and then holding down the Shift key while pressing an arrow key to move the highlighted entry up or down in the list.  You can also delete an entry by holding down Shift and pressing the Del key.  

If you are working with greyscale maps whose lines are faint, you can enhance them.  If this is the case, it is sensible to use ICE's Structured Panorama option and save your individual tiles in serpentine order.  You can move either column-wise or row-wise, but you must use the same choice for all image tiles when capturing them.  If the images don't match well after ICE runs, try setting the Search radius to a higher value and use overlap values which are roughly the same as those used when making the tiles. If you have left out an image, you can return to the site image and capture the omitted area.  The file name of this image will be added to the editing list at the bottom,  Move it up as described above so that it lies between the capture tiles adjacent to the omitted area.



Many GeoPortal programmes permit movement by fixed amounts in the horizontal and vertical directions, and these usually overlap fairly well. For full greyscale or coloured images, it is usually sufficient to use the New Panorama option, which is the default in ICE.

Calibration:

Images captured from GeoPortal sites can not be calibrated automatically for use in AirPhotoSE.  Many Geoportal sites show the coordinates at the mouse cursor in either a local grid or in latitude and longitude. If a map shows a national or international grid, then you can note the numerical values for at least four grid crossing points to use in AirPhotoSE's calibration option.  If these values are in a national grid, then they can be converted to their latitudes and longitudes with a free utility like GeoTrans, see:

National Geospatial Intelligence Agency

If no grid is shown, you can note the coordinates of prominent features which you will be able to see easily when the images have been saved and displayed in AirPhotoSE. Google Maps  for example, shows the latitude and longitude at any point with a right click and places this into it's Search field.  From there it can be copied to the clipboard.  If you have opened Notebook before opening GeoPortal, you can paste this value along with those of other easily recognised points into the Notebook page from which they can then be pasted into the AirPhotoSE calibration dialogue box. If the GeoPortal site offers a coordinate search facility, then Calibrating GeoPortal Variants as described in a later chapter may save some work.

Special Sites:

A few GeoPortal sites use external programmes to implement special needs.  For example,  the site at the Belgian Royal Library which offers full resolution views of all 275 140 x 90 cm sheets of one of the earliest set of large scale maps made in Europe, the Carte de Ferraris completed in 1777, requires that the Adobe Shockwave Player be installed if the imagery is to be seen at full screen resolution along with panning and zooming at maximum speed.  This must be installed by a user with administrative rights in the Microsoft Internet Explorer, version 8 or later before attempting to view the site in AirPhotoSE. The free download installation file may be found at:

http://www.adobe.com

and there, choose:



Other sites may use the Flash Player from the same source.  Please consult the documentation for any site of interest to see if there are special requirements.

A very few sites require the latest version of the Oracle Java runtime environment.  An example is the digital orthophoto viewer from the German Bundesamt für Kartographie und Geodäsie.  

http://sg.geodatenzentrum.de/web_dop_viewer/dop_viewer.htm

It offers two viewers, one for Java script which is built into all browsers, and one for Oracle's Java which gives the site a higher resolution display and a faster and better search engine.  If you choose the Java version, AirPhotoSE will spawn the Internet Explorer in a separate window so that it can be run in stand-alone mode.  

You can force any GeoPortal site to use the Internet Explorer by clicking on the "Use IE" on the GeoPortal menu and making sure that the Use IE tab is checked.  For frequent use, put [ie] in the GeoPortal list in the space to the left of the URL address to save having to select Use IE from the menu each time you open it.