Instructions for use
Upon logging in to geo-wiki.org (either as guest or registered user), assuming you have properly configured your browser for Activated JavaScript and the Google Earth Plug-in (see main page), you will be presented with the following screen:
On the left panel you will see the menu list which is currently set to "show none". By clicking on the different radio buttons, you can overlay various land cover and disagreement datasets on Google Earth. Clicking on any of these will automatically display the associated legend below the menu.
The first three options are to show MODIS, GLOBCOVER or GLC2000 original land cover data. Clicking on any of these will display the associated legend below the menu, with the option to show details of the legend classes. Further, you may show the overall disagreement map, which shows total forest and cropland disagreement among all three land cover datasets. For closer examination of disagreement between the datasets, it is then possible to view cropland and forest disagreement maps separately for each combination. Finally, you may wish to load basedata, which adds the standard Google Earth planimetric data to the overlay, along with loading Panoramio photos.
If you select one of the various datasets above for visualization, and zoom in or out, the dataset will automatically refresh itself (by default) based on the new resolution. The following screens shows you the displayed Overall Disagreement Map:
If you do not wish it to auto-refresh, you may click this box off. Manual refresh is always possible by clicking Refresh. If you are ready to begin validating, or wish to go to a location that you know, you may type the name in the box available and click Go to location.
On the top right of the screen you will see the current status of your session, which will appear as below when you first login:
Before you can begin to validate the maps, you must zoom in to a desired location for validation. It is recommended that unless you have local knowledge, you choose areas that are covered with high resolution images. At approximately 10000 meters above the ground, your status will change. If you are currently logged in as a visitor, the following message will appear:
If you wish to proceed with the validation, you must return to the home page by logging out and then registering yourself. If you have registered, you will instead see your status change to the following:
At this stage you are now ready to begin the validation. For validating you have two options: either ALT + left mouse to validate individual pixels from the three datasets; or CTRL + left mouse to validate an entire area (e.g. large homogenous blocks of land cover such as desert or forest). Using ALT + left mouse will bring you to the screen below. This shows you the representative pixel from each of the three land cover datasets for the location that you identified. The smallest in red (GLOBCOVER), the next largest in dark blue (MODIS) and the largest in light blue (GLC 2000) all drawn to scale.
In the panel on the right, you will see the following options for validation as shown below. You will notice that the pixel colors match those in the menu. Both the name of the datasets (in the left column) and the assigned classes (in the right column) are color coded. In the middle, you have the option to click on either correct, not sure or incorrect for each of the three land cover datasets.
If you have uploaded or found pictures on an online photo website (e.g. Panoramio), it is possible to click on "show", and enter the URLs for those photos, even including the cardinal direction and date if you know it.
Additionally, if you made the validation using Google Earth high resolution image, please click the Highres image box.
Finally you may click the Submit button to submit your validation to the geo-wiki database. Alternatively you may click Cancel to leave the validation.
If you wish to validate a larger area (e.g. large homogenous blocks of land cover such as desert or forest), it is possible to use CTRL + left mouse twice, first clicking on one corner of the desired area, then on the opposite corner. You will then be able to see the selected area and if that is correct, begin to validate, or if incorrect, cancel and retry. The menu options are identical to the pixel validation.
