Converting Geo-coordinates per Macro

[Martin Hauer]

I would like to convert Geo-coordinates with a click on a button in a Tiddler.

The coordinates should be converted from i.e. N 47° 04.624' to 47.077067° and then a Google-Maps link should be created (<a href="http://maps.google.at/maps?q=47.077067+015.437033" target="_blank"> [img[in Google Maps anzeigen|GoogleMaps_Logo_36.gif]] </a>)

Unfortunately I'm a beginner in writing Macros in TiddlyWiki.

The coordinates are stored in fields in the Tiddler like so:

Field1 = N

Field2 = 47

Field3 = 04

Field4 = 624

Field5 = E

Field6 = 015

Field7 = 26

Field8 = 222

Could anyone please help me in solving this problem?

Thanks in advance, Martin

[Eric Shulman]

On Thursday, April 30, 2020 at 7:31:18 PM UTC-7, Martin Hauer wrote:

I would like to convert Geo-coordinates with a click on a button in a Tiddler.

The coordinates should be converted from i.e. N 47° 04.624' to 47.077067° and then a Google-Maps link should be created (<a href="http://maps.google.at/maps?q=47.077067+015.437033" target="_blank"> [img[in Google Maps anzeigen|GoogleMaps_Logo_36.gif]] </a>)

Field1 = N

Field2 = 47

Field3 = 04

Field4 = 624

Field5 = E

Field6 = 015

Field7 = 26

Field8 = 222

The formula for converted from DMS (degrees,minutes,seconds) to DD (decimal degrees) is: DD = D + M/60 + S/3600

Note that in your example, you are specifying degrees=47 and minutes=4.624  (using two fields to hold integer and decimal portions of the minutes value).

Thus, for D=47, M=4.624, we calculate: DD = 47 + 4.624/60 = 47 + 0.077067

To get this value using TW Math Filter operators, we can write:

{{{ [{!!field2}] [{!!field3}divide[60]] [{!!field4}divide[1000]divide[60]] +[sum[]multiply[1000000]round[]divide[1000000]] }}}

* get the value from field2

* get the value from field3 and then divide by 60

* get the value from field4 and then divide by 1000 to shift the decimal point to the left and then divide by 60

* add these values

* then, to round to 6 decimal places, multiply by 1000000, round to the nearest integer and then divide by 1000000

Thus, to get the latitude and longitude as variables, we would write:

<$vars latitude={{{ [{!!field2}] [{!!field3}divide[60]] [{!!field4}divide[1000]divide[60]] +[sum[]multiply[1000000]round[]divide[1000000]] }}}>
<$vars longitude={{{ [{!!field6}] [{!!field7}divide[60]] [{!!field8}divide[1000]divide[60]] +[sum[]multiply[1000000]round[]divide[1000000]] }}}>

and to construct the desired URL, we can use the title[] and addsuffix[] filters, like this:

<$vars url={{{ [title[http://maps.google.at/maps?q=]addsuffix<latitude>addsuffix[+]addsuffix<longitude>] }}}>

Then, we can display the link this way:

<a href=<<url>> target="_blank"> [img[in Google Maps anzeigen|GoogleMaps_Logo_36.gif]] </a>

Putting it all together:

<$vars latitude={{{ [{!!field2}] [{!!field3}divide[60]] [{!!field4}divide[1000]divide[60]] +[sum[]multiply[1000000]round[]divide[1000000]] }}}>
<$vars longitude={{{ [{!!field6}] [{!!field7}divide[60]] [{!!field8}divide[1000]divide[60]] +[sum[]multiply[1000000]round[]divide[1000000]] }}}>
<$vars url={{{ [title[http://maps.google.at/maps?q=]addsuffix<latitude>addsuffix[+]addsuffix<longitude>] }}}>
<a href=<<url>> target="_blank"> [img[in Google Maps anzeigen|GoogleMaps_Logo_36.gif]] </a>
</$vars>
</$vars>
</$vars>

enjoy,

-e

Eric Shulman

TiddlyTools.com: "Small Tools for Big Ideas!" (tm)

InsideTiddlyWiki - http://TiddlyTools.com/InsideTW

[Martin Hauer]

Hi Eric,

many thanks to this solution and the detailled description!

With this it is easy to understand how it is accomplished.

I use TiddlyWiki for so many years now and it is always great to see how many different things can be accomplished with it!

Thanks again!