WO1986006898A1

WO1986006898A1 - Device for receiving and presentation of weather forecasts and weather data

Info

Publication number: WO1986006898A1
Application number: PCT/SE1986/000205
Authority: WO
Inventors: Bengt Carlqvist; Anders Bauer
Original assignee: Bengt Carlqvist; Anders Bauer
Priority date: 1985-05-08
Filing date: 1986-05-05
Publication date: 1986-11-20
Also published as: SE8502273L; SE8502273D0; EP0255521A1

Abstract

A device for receiving and displaying weather forecasts and weather data which can be used by weather-dependent community throughout the country. The device utilizes a channel transmitting together with the ordinary broad casting programs and containing coded weather information from a transmitter in the form of a data groups (G). Each group contains a forecast head (PH) and associated fore casts data sections (PD) indicating the weather information. The device contains a signal receiving unit (1, 4, 5, 6) which recovers data signals representing the groups (G), as well as a signal processing unit (7, 8, 9, 10, 11) and a display unit (15). The signal processing unit contains a decoding unit (7) for decoding the signals recovered from the signal processing unit and for indentifying the weather information in the groups. Moreover, there is a forecast memory (9) storing forecast data (PD) on addresses determined out of the forecast head (PH) as well as a control unit (11) controlling the read out of the forecast memory and storing forecast (PD, PD2, ...) associated with one or more groups (G). The weather symbols can be stored in a special symbol memory (10) or in the display unit (15) which is controlled by the control unit for display of the weather forecast.

Description

P§ i9®_f2ϊ_ϊ.§-._:i iS§_-.5^_E-.®§-.SΪ !i25-.2f_^'i-^r?§ther_forecasts and weather data

Technical field

This invention relates to a device for receiving and presentation of weather forecasts and weather data according to the preamble of claim 1. The device is intended to be in¬ cluded in equipment usable, above all, in weather-dependent sectors such as the agricultural, building and transport sectors but also by the public. State of Art

On the radio and TV, current weather forecasts are given at fixed times and current forecasts are reproduced in newspapers at the time of printing. Weather forecasts have been supplied for a long time in this way. The development so far has been to improve the reliability of the forecasts and to give forecasts for long periods.

As the forecasts are given a form covering the whole country in public media, the regional dissolution will be bad resulting in local deviations from the forecast. This problem has been reduced in later years by supplementary forecasts via local radio broadcasting.

A special type of radio receivers for transferring weather information is previously known e.g. from

GB patent 2 078 468. Gale warnings to ships can be trans¬ ferred by means of this known device via the long wave band having a great range. Thus, this device gives immediate information about a certain type of weather to a receiver but is not limited to certain wind information for certain geographical areas within coast and sea. The known device does not give any presentation of current weather fore¬ casts or other weather data on a display unit.

The new method for transferring forecasts implies that constantly updated forecasts with a high regional dis¬ solution for different time periods can be continuously transferred to the users at optional places throughout the country and throughout the twentyfour hours without any demands for line connections. Thus, it is the object of the invention to provide a device for essentially increasing and simplifying the presentaion of weather forecasts to a plurality of user groups by a) updating a forecast already presented without any essential delay and independently of fixed times, and b) storing the received forecasts so that these are avail¬ able at any time for presentation.

The device of the invention is characterized as is apparent from the appended claims. Brief description of drawings The invention will be described in greater detail with reference to the accompanying drawings, wherein

Fig 1 shows a diagram of the base band coding structure for a radio data system;

Fig 2 shows a diagram of a format for building up the weather forecast information within the structure according to Fig 1 ;

Fig 3 shows an example of a format for transmission of certain weather information;

Fig 4 shows a block diagram of an embodiment of the device according to the invention;

Fig 5 shows a block diagram of an embodiment of a control unit included in the device according to Fig 4;

Fig 6 shows a flow chart;

Fig 7 shows a block diagram of another embodiment of the device according to the invention;

Fig 8 shows a block diagram of an embodiment of a control unit included in the device according to Fig 7.

In the following part of the specification a general presentation of the information channel for transmission of weather information is first given. After this a description of the device according to the invention for two different alternatives, alternative I and II, will follow.

The channel to be used for transmission of weather information is the so-called RDS-system. RDS is specified in reference IJ . RDS is based on sending inaudible signals together with the usual radio programs. RDS can be utilized in FM-broadcasting within the frequency range 87.5-108 MHz. The transmitters are frequency modulated by a tone of 57 kHz to +3 kHz deviation which is a subcarrier of the data signal. The subcarrier is product modulated by a signal formed by phase modulating a tone having the frequency 1187.5 HZ with differentially coded binary information. The base band coding structure of RDS is shown in Fig 1. The greatest element in the structure is called a group G. Each 5 block consists of an information word PM of 16 bits and a parity word PM of 10 bits.

Moreover, in Fig 1 an information word of the block B is shown in greater detail which comprises a group type code GRT, a version bit V, an identification code of traffic 10 programs TP and a code PTY for the program type.

[ij "Specification of the radio data system RDS for VHF/FM sound broadcasting", European Broadcasting Union Tech. 3244-E, March 1984. Weather information structure 15 Only group types of version A are intended to be used for weather forecast information meaning that a group G may contain 5 bits from block 2, + 16 bits from block 3, + 16 bits from block 4 = 37 bits of weather information. In Fig 2 an example of a format for building up the information for 20 forecast transmission is shown. According to the example above 15 of these 37 bits are used for a so-called forecast head PH, and the remaining 22 bits for forecast data PD. In the forecast head PH there is information as follows: Ii.E®-.° -.f°Iϋ__: §-_:i 3 bits will give a possibility for 8 25 different types of forecasts. Possible

PR types are e.g. agricultural forecasts, building weather forecasts, general fore¬ casts, sea forecasts etc. y!25£∑- • For the types of forecasts requiring more 50 than 22 bits of information transmission

D the forecasts are subdivided into sub¬ sets. 2 bits give 4 possible subsets, im¬ plying that a forecast in this example may contain at most 4 x 22 = 88 information- 55 bits.

Forecast_range: 6 bits give a divison into 64 different P_Q forecast areas corresponding to what SMHI* has intended for Sweden,

40 * (The Swedish Meterological and Hydrological Institute) . Validity^ 4 bits give 16 different validity ranges, _rτ meaning that both forecasts for the next hours and several days ahead can be transmitted. If the symbols used on the display unit and/or the whole display design might be changed via the RDS-channel one or more codes in the forecast head can be forbidden and are in¬ stead reserved for the application, for example, that only seven different types of forecasts can be transmitted and that the code 000 is then reserved for symbol transmission. If one type of forecast requires an information trans¬ mission of more than 22 bits, i.e. cannot be contained with¬ in the allotted space in a group G (Fig 2), the information transmission must be distributed on several groups through subsets. Thus, one subset belongs to one single group. The next subset in the fo'recast type is transmitted either within the following group or possibly by jumping over a number of groups intended for another purpose than weather information. The forecast information can look quite different depending on which forecast (shipping, agriculture etc) is concerned. In Fig 3 an example of information for an agricultural forecast is shown. For an agricultural fore¬ cast the following information may e.g. be transmitted in the forecast data sections PD1 , PD2, PD3 in the following subsets D1-D4:

Subset_D1 (00); (Forecast section PD1) Tγpe_of_weather: 16 different types of weather can be indicated by 4 bits, e.g. clear, alternating cloudiness, overcast, drizzle, ceasing rain, thunder etc.

Temperature^ 7 bits are used for the temperature range -60 to +60°C and 2 bits are used to indicate the tendency for the validity interval (increasing, de¬ creasing or unchanged) .

Humidity^ 7 bits are used to indicate the relative humidity (0-100 and 2 bits are used to indicate the tendency.

: (Forecast section PD2)

Rain > 0,5_mm_ 4 bits are used to indicate the probabili¬ ty (0-100 , in 10% steps) for more than 0.5 mm rain during the validity range. 2 bits are used to indicate the tendency.

B ϊ-.-.>-.2_.5}5i 4 bits are used to indicate the probabili¬ ty for more than 3.0 mm rain during the validity range. 2 bits are used to indi¬ cate the tendency. F£ost_risk^ 4 bits indicate the probability for frost.

2 bits indicate the tendency.

Textual_messagesj_ 16 different fixed textual messages

(stored in the receiver) can be presented by 4 bits. For example, warning of night frost, warning of thunder storm.

Subset_D3_(1.0)_ (Forecast section PD3)

Wind_direc"tion and._wind._force^ 3 bits are used to indicate direction of the wind (N, NW, W, SW, S, Se, E, NE) . 3 bits are used to indicate the wind force (according to accepted grouping of wind force) and 2 bits are used to indicate the tendency of the wind force. Reserve^ 14 bits in subset D3 (10) and the whole subset D4 (11) are in reserve. For e.g. a forecast for building weather another type of weather information is transmitted but the information is built up in a similar way.

As the information is transmitted continuously to the users they will receive the latest forecast made on each occasion. If the receiver is active continuously the fore¬ cast information can be presented immediately. If the receiver is inactive the object is that the user should not need to wait for more than about 10 min. from activation of the receiver before the selected forecast can be presented. Thus, as a summary, the weather information is trans¬ mitted from a weather station to one (or more) sub¬ scribers intended to utilize the weather information by means of an available radio channel supplied by the tele- communication authorities of the country for presentation on the subscriber's disply unit. The transmission is carried out in the form of two main blocks within the groups forming the base band structure of the radio transmission. These two blocks are a) a forecast head PH1 , PH2, PH3 ... for transmission of one or more of the information types forecast, subsets, forecast area and validity, and b) forecast data PD1 , PD2, PD3 ... for transmission of the weather information (rainfall, temperature, pressure etc) associated with the relative forecast head.

Embodiments

Alternative I

In the block diagram according to Fig 4, and embodiment of the receiving device according to the invention is shown, where the blocks 1, 4, 5, 6 represent the known units included in a known receiver for reveiving the information transmitted according to the so-called RDS-system described in the above-mentioned technical report. The block 1 is an FM-receiver which consists of a conventional UHF/FM demodulator. A product-modulated sub- carrier is obtained across its output. This is filtered in filter means not shown in order to let through a signal having a frequency about 57 kHz which gives a signal containing the differentially coded and phase-modulated data signal for weather information. This signal is supplied to a data detector 4 for decoding, and an unsynchronized data signal of a certain rate, e.g. 1187.5 bits/sec, is obtained across its output. This data signal is supplied to an error correction unit 5 which can consist of a shift register network for decoding and for performing error detection (see e.g. Fig 18 in the above-mentioned reference). The signal from the output of the detector 4 is also supplied to a group and block synchronizing unit 6 described in Fig 19 of the above-mentioned reference. The unit 6 will then supply group and block synchronizing pulses to the error correction unit 5 in known manner.

Thus, a digital signal in the form of digital data bits in the form of series (64 bits per group G according to Fig 2) is received across the output of the unit 5. These represent group and block synchronized and error corrected data of the subsequent receiver unit.

The characterizing feature of the inventive device is the design of the receiver unit to the right of the dashed line according to Fig 4.

This part of the receiver device contains staticizer 8, a group type decoder 7, a first memory unit 9, the so-called forecast memory, a second memory unit 10, the so-called symbol memory, a control unit 11, a first selector 12 for selection of type of forecast, a second selector 13 for selection of forecast time, a third selector for selection of forecast area and a display unit 15. The function of the units in the receiving unit will now be described in greater detail. 27 bits of the 64 bits per group G transmitted from the error correction unit 5 are always used for special in¬ formation. The remaining 37 bits per group G can be used for weather information according to Fig 2, viz. for the forecast head PH and for forecast data PD. In the alterna- tive I described herein the forecast head is used in each subset (according to Fig 3) while only one forecast head PH is used for all subsets D1 , D2 , D3 ... associated with several associated groups of the same type in the alterna¬ tive II described later. Of course there may be cases when there is room for PD together with forecast head PH within one single group G. 15 bits of the 37 bits for weather information form a forecast head and the remaining 22 bits contain forecast data. However, the invention is not limited to said number of bits and contents for forecast head and forecast data, respectively.

The error correction unit 5 transmits digital data bits in the form of series, 64 bits per group G. Conversion of the 37 bits containing weather information takes place in the staticizer 8. The forecast head PH is obtained across the first output bus "15" and is supplied to an address input AW of the forecast head 9. Forecast data PD is ob¬ tained across the other input bus "22" and supplied to the data input DW of the memory 9 to be entered into this memory on an address defined by the 15 address bits of the address input AW. The four GRT-bits in block B2 according to Fig 2 are clocked into the group type decoder 7 and decoded. If the group G is a group type with weather information an activation signal is emitted from the decoder 7 to the E-input ("enable") of the forecast memory 9 and the fore¬ cast data is intered into this memory in the address indicated by the forecast head. This memory has an additional address input AR as well as a data output DR connected to the control unit 11 for addressing and feeding out the forecast data to this unit, as described below.

In the symbol memory 10 the various weather symbols are fixedly stored and can be fed out via the data output DR upon addressing from the control unit 11.

The forecast memory can consist of a

memory (RAM) while the symbol memory preferably consists of a read memory (ROM) .

Three selectors are connected to the control unit 11 in this embodiment, viz. the forecast type selector 12, the forecast time selector 13 and the forecast area selector 14. These can be activated by the user in a suitable manner, e.g. from a panel on the display unit 15, where push-buttons are arranged in known manner and electromechanically connected with the relative selector. Upon activation of the respective selector 12, 13, 14, type of forecast, validity interval and area of the forecast are selected for the fore¬ cast that the user will have presented on the display unit and in the form of the symbols stored in the symbol memory 10. Thus, the different symbols for different types of weather forecast data are stored in the symbol memory. The symbols are stored in a way adapted to the desired display unit. If the display unit consists of a graphical LCD-dis¬ play, each symbol can for instance be built up by a number of words in the memory with a certian word length. The symbol memory can also consist of a read-write memory (RAM) , and it is then possible to realize the receiving device so that the symbols can be changed at the RDS-channel.

The control unit is shown more closely in Fig 5. This contains a subset memory 111 for storage of the number of subsets required for a certain type of forecast and has its address input connected to the output of the selector 12. An address generator 112 has four inputs connected to the outputs of the selectors 12, 13 and 14 and to the output of the subset memory 111. The output of the address generator 112 is connected to the address input AR of the forecast memory 9.

The block 113 consists of a combined forecast data decoder, address generator and presentation unit driver. This block has three inputs for receiving signals from the respective selector 12, 13 and 14 and a fourth input for receiving the output signals from a staticizer 114 which is connected to the output DR of the forcast memory 9. Thus, forecast data are fed to the block 113 from the output of the staticizer 114. The three inputs from the relative selector output are only activation inputs to the block 113 for selected forecast (type, time or area).

The read address of the selected forecast data in the forecast memory 9 is generated in the address generator 112. The number of subsets of the different forecast types are stored in the subset memory 111. The selected forecast type forms the address (A) of the subset memory 111 and the out¬ put data (D) from the subset memory 111 will then indicate the number of subsets of which the selected forecast type consists. The number of subsets is an input signal to the address generator 112. If the forecast data of the chosen forecast type consists of more than one subset, the address generator 112 will generate the addresses of all the subsets.

A forecast data (DR) from the forecast memory 9 is supplied to the staticizer 114 in the control unit 11. The forecast data is thereafter shifted from the staticizer 114 to the block 113. The addresses for selected forecast data are generated in an address generator 112 at even intervals so that a possible new forecast data received and entered into the forecast memory can be presented directly. I Fig 6 an overall flow chart of the included funtions in forecast data decoder, address generator and display unit operating means is shown. The whole block 113 is preferably realized by the aid of a microprocessor as well as associated programs according to the flow chart. This microprocessor can of course also be utilized for the functions described above. Alternative II

Fig 7 shows a block diagram of the receiving device according to the invention in the second alternative. Like alternative I the forecast data in this second alternative is divided into several subsets where one subset is emitted per group. However, in alternative II only the subset in the first group G (Fig 2) contains forecast head PH with in¬ formation about forecast type, area and validity. The sub- sets which follow in the next groups only contain additional forecast data PD and therefore utilize available capacity better.

The units shown in the block diagram according to Fig 7 have their counterparts in the block diagram according to Fig 4 except for the control unit 11. Moreover, the staticizer 8 has been provided with two outputs where the output P feeds out forecast head information and output PS feeds out one forecast start bit. The information P and PS is available in the data signal from the error correction unit 5 entering the staticizer 8. The address input AW of the forecast memory 9 is in this case connected to the control unit 11 as well as the output GT of the group type decoder 7.

Fig 8 shows the control unit 11 in alternative II in greater detail. This contains a register 116 for parallel loading of the data signal P (13 bits), the forecast start bit PS (1) and the signal GT (1) from the group type decoder 7. The loading of the data signal P is activated by the forecast start bit PS. Moreover, a first address generator 117 for forming a writing address for entering the data signal from the converter 8 via the input DW of the forecast memory 9 and a second address generator 118 to form a read address when feeding out data from the fore¬ cast memory 9 to the parallel staticizer 114 are included. A subset memory 121 corresponding to the subset memory 111 according to Fig 5 is connected to the address generator 117 via a demultiplexer 120. The output of the register 116 is connected to the address generator 117 for supplying the forecast head to this and is further connected to one input of a multiplexer 119 for multiplexing the type of forecast by the type of forecast selected from the forecast type selector 12. The block 113 is of the same design as the corresponding block in Fig 5.

When a current type of groups for weather information has been received containing forecast head the signal GT from the group type decoder and the signal PS, the forecast start bit, from the staticizer 8 are activated by the data signal. The forecast head information is then entered into the control unit 11 via the data signal P. When type of forecast, area and validity have been decoded in the address generator 117 the associated memory area is indicated by address AW in the forecast memory 9, the forecast data in the subsets being stored in the memory 9 via the input DW of the memory 9. When the next subset is received, the group type signal GT is activated as before. However, the forecast start bit PS (=0) is not activated, and therefore no new forecast head is entered into the control unit 11. Instead a new address is calculated when the address generator 117 is activated by means of the group type signal GT. The new address AW points out the new address of the subset in the memory 9. According to the above the subset memory 121 contains information how many subsets the relative type of forecast contains. Upon presentation of forecast the desired forecast type, forecast time and forecast area are selected by means of the selectors 12, 13, 14 connected to the control unit 11. After this the read address AR where the desired forecast is stored is generated from the address generator. The same subset memory 121 as that for the address generator 117 can then be used to generate all the addresses of the associated subsets.

When the read address has been generated, stored fore¬ cast information can be read from the forecast memory 9 via the staticizer into the block with forecast decoder, address generator and presentation unit driving means. This block has the same functions and operates in the same way as in the control unit 11.

In order that the subset memory 121 might be utilized both at entering of forecast type across "3" (Fig 8) via the address generator 117 to the forecast memory 9 and upon addressing via the address generator 118 at read-out of data via DR of the symbol memory 10, a multiplexer 119 and a demultiplexer 120 are provided. When reading of forecast type across "3" is to take place the multiplexer 119 is in such a position that its input a_* is activated, the forecast type being entered into the subset memory 121. At the same time the demultiplexer is in such a position (due to the synchronous connection) that information about the number of subsets from the sub¬ set memory 121 the address generator 117 is given across its output a-■>

When addressing from the address generator 118 is to take place for reading from the forecast memory 9 the input b^ of the multiplexer 119 is activated (from the forecast type selector 12) and an activation signal across the out¬ put b₂ from the demultiplexer 120 is emitted to the address generator 118 for the read-out.

The forecast data coder included in the block 113 receives a forecast data read from the memory 9 and de¬ codes this so that an address to the address input AR of the symbol memory is obtained and so that read-out of the symbols responding to the forecast data takes place across the output DR, see the flow chart according to Fig 6. These are thereafter fed to the following display unit 15 by means of the display operating means included in the block 113 in the same way as in alternative I above according to Fig 5.

In the embodiments according to alternative I and II described above the symbol memory consists of a separate memory unit 10.

It is also possible that the display unit 15 consists of a unit adapted to the customers and with predetermined fixed symbols on definite places. These can then be activated directly from the control unit instead of, as in a graphical display unit, activating point by point and building up in this way different symbols. The symbol memory can then be excluded by such a unit adapted to the custormers as the symbols in this case are "stored" on the display unit. In the illustrative examples shown, the control unit, after entering a current forecast data from the forecast memory and decoding this, will instead generate signals directly to the display unit for activation of the current symbols.

The address generation function in unit 113 in the control unit 11 in Figs. 5 and 8, respectively, will then^' be unnessary.

In the flow chart in Fig 6 the activities "fetch text and display on the display unit" are then changed into "generate activation signals to the display unit for activation of current symbols on the display unit".

Claims

1. A device for receiving and presenting weather fore¬ casts and weather data, containing information about various forecast categories- such as one or more of the categories area, time and type of weather information and which are transmitted via a certain channel in a certain transmission medium, e.g. a channel superimposed the program channels in the FM-bands of the broadcasting net in the form of data groups, of which groups (G) at least one contains a forecast head (PH) indicating said forecast category and at least one forecast data section (PD) associated with said forecast head (PH) and indicating the weather information, said device containing a signal receiving unit of a structure known per se for recovery of the data signals representing said groups (G) and a data receiving unit containing a signal processing unit and a presentation unit (15), c h a r a c t e r i z e d in that the signal processing unit comprises a) a decoding unit (7) for decoding the data signals recovered from the signal receiving unit (1,4,5,6) and representing said groups (G) , the group type of weather information being identified, b) a forecast memory (9) , which is activated by said decoder (7) when said data for weather information have been identified in order to store the forecast data (PD) out of the received data signals from said forecast data sections (PD1,PD2...) on addresses determined out of said forecast head (PH or PH1 ,PH2, ...) , c) storing.means (10,15) for storage of the symbols representing together a possible weather forecast given from said forecast information which is displayed in the display unit (15). d) a control unit (11) for decoding the different statements as to weather type, air humidity etc, contained in a forecast data section (PD1) and for generation of an address to said forecast memory (9) , the forecast data (PD1 ,PD2) associated with one or more forecast data sections (PD1 ,PD2) being read and stored.

2 . The device of claim 1 , c h a r a c t e r i z e d in that it contains, moreover, at least one selector unit (12,13,14) for selection of the desired forecast category out of a definite number of categories such as type, time or area of forecast, said control unit (11) being activated upon activation of the selector unit for reading the selected forecast stored in the forecast memory (9) and belonging to the selected category and activating said storing means (10,15) for reading the symbols belonging to the selected forecast and utilized by the display unit (15) .

3. The device of claims 1-2, c h a r a c t e r i z e d in that said storing means consist of a symbol memory (10) storing the symbols utilized by the display unit (15) at display of the current weather forecast, the symbol memory being addressed from the control unit (11) for reading where decoding is carried out in order to generate a dis¬ play point by point on the display unit (15).

4. The device of claims 1-2, c h a r a c t e r i z e d in that said display unit consists of a unit adapted to the customers, said storing means consisting of symbols stored on the unit which are activated by the control unit (11).

5. The device of claim 1 in the case when each subset contains both forecast head (PH1,PH2...) and forecast data (PD1 ,PD2 , ... ) , c h a r a c t e r i z e d in that the staticizer (8) has a first output (15) for feeding forecast head information (PH) to a write address input of the forecast memory (9) and a second output (22) for feeding forecast data to a writing input for data of the forecast memory (9) and that the control unit (11) contains a) a first memory unit (111) for storage of the number of subsets (D1,D2,...) belong to a certain type of forecast and being addressed by one of said selectors (12), b) an address generator (112) which forms an address in dependence on the number of subsets stored in the first memory unit (111) and the output quantities from one or more of said selectors (12,13,14), for read-out of forecast information from said forecast memory (9) , and c) a microprocessor unit (113) for decoding the stored forecast data upon activation from one or more selectors (12,13,14) and for addressing said storing means (10) so that the weather symbols responding to said forecast in- formation are presented on the display unit (15).

6. The device of claim 1 for the case when there is only one forecast head for subsets (D1,D2,...) belonging to several groups (G) . c h a r a c t e r i z e d in that the forecast head information from said staticizer (8) is divided into forecast start information (PS) and forecast head information (P) , the control unit (11) containing a) recording means (116) for storage of said forecast head information (PH) , b) a memory unit (121) for storage of the number of subsets (D1,D2,...), c) a first address generator (117) for generating an address to the writing address input of the forecast memory (9) in dependence of the stored forecast head information (PH) and the stored number of part quantities in order to write forecast data associated with subsets from several groups (G) , d) a second address generator (118) for addressing the forecast memory (9) in dependence on the number of subsets stored in the memory unit (112) and in dependence on the output quantities from one or more of said selectors (12,13, 14), for output of forecast data (PD) associated with the selected weather information (type, area, time), and e) a microprocessor unit (113) for decoding the fore¬ cast information fed from the forecast memory (9) upon activation of the correspondning selector (12,13,14) and addressing said storing means (10) so that the symbols associated with the forecast information are presented on the display unit (15).