Here you do find an explanation on:
- the filters under the tab "Home"
- visualization of data
- downloading via an FTP program (to be included)
- answers to frequently asked questions (to be included)
The use filters under "Data"
To find data that are of interest, you can use the search filters. There are three filters: the "what", "where" and "when" filter. These three filters work independently, but results are only shown if the criteria of all three filters are met (technical: the searches are combined with a logical AND operator).
The "What" filter
This filter allows you to search by (parts of) keywords in all the text fields of the metadata of the data sets. The filter searches for whole words which you specify it in the window. You can enter multiple keywords. All words must occur somewhere in the text of the description of the data set. The order does not matter. As a separation between the search words you can use either a space, comma or semi-colon (;) use. The filter searches in both the Dutch and English description of the dataset.
To search for a part of a word, you can use the special characters '*' or '?'. The question mark "?" represents exactly one character on that position in the keyword, the asterisk "*" means that there are 0 or more characters at that position. Two examples:
- keyword "r?in": result are datasets with for example in the text fields somewhere 'rain' or 'rein' ..
- keyword 'rain*': result are datasets with for example in the text somewhere 'rain', 'rainfall' or 'raingauge' ..
The "Where" filter
Of each dataset the four geographical boundaries (in latitude and longitude) of the data area in which all of the data contained in the dataset are located. Additionally, in most databsets also the geographical boundaries for the data in the file itself are included. If you are looking for a location, enter the border (in latitude and longitude) of the area you are interested in the "Where" filter.
The filter searches first for datasets covering all or a part of the specified search area. The datasets that meet these requirements are then displayed and of these datasets only the datafiles whose area fully or partially coincide with your specified search area are listed.
The filter searches in areas rather than precise locations. For example you are looking for information about the temperature in your hometown. A dataset with temperature data from all Dutch stations will overlap with your query. But if your hometown does not coincidence with a KNMI station you will not find data on your place of birth.
A dataset that has the whole world as coverage area will always appear as a search result when using the "Where" filter.
The "When" filter
For each dataset the date and time of the oldest and most recent data record are captured. This also applies to the datafiles themselves. Some datasets are on going as data are added continuously. For these data sets the current date and time will be held as end date. If you enter a start and/or end date the filter searches first datasets that have an overlap with the given search period. Then the filter searches within the datasets found for those datafiles that have an overlap with the search period specified.