[Therion] Georeferenced PNG export problem - Bug in Xtherion "\help\Calibrate bitmap"

[Evaristo Quiroga]

I have found a bug in the Xtherion command  "\help\Calibrate bitmap".

The command does not work when the longitude is between Greenwich and 1 
degree west (example -0.2333). I do not think it should work for the 
latitudes between the equator and 1 degree south.

I think the problem comes from the "ll2ozi" function of the Xtherion 
"mapcalc.tc" file. It takes the integer value of the longitude and 
latitude (int [$ lat]). When the longitude  is between 0 and 1 of west 
corresponds a negative value of 0, which the integer function considers 
a error.

The problem is that I just have two karstic zones that are located in 
those longitude.

As long as that error is not corrected I have developed in following trick.

    /Process twice the pdf file with the command //"\help\Calibrate
    bitmap". /
    /With the first execution I create the png file. //Later it changed
    the name to the pdf, and I open it in an editor, //and search
    "thCalibrate". //I eliminate the minus signs of the coordinates (L,
    F). /
    /Execute again //"\help\Calibrate bitmap" with this new file,
    generating the file ".map". //I open and edit the .map file changing
    the E by W in the coordinates. /
    ///Finally I rename the ".map" file to match the first created png
    file./

It works but it is a bit cumbersome.

Regards,

Evaristo.

El 26/03/2018 a las 13:25, Evaristo Quiroga via Therion escribió:
> The reverse engineering is not with the PDF. Martin do a good job here 
> putting in all the therion output pdf a comment with the reference. 
> You only have to open the file and search "thCalibrate". You found the 
> next text:
> /
> ///thCalibrate0 (X=-22.16017pt, Y=260.12132pt, L=-0.3641990570, 
> F=42.2992656650) //
> ///thCalibrate1 (X=1921.38345pt, Y=199.8752pt, L=-0.3608862211, 
> F=42.2991894208) //
> ///thCalibrate2 (X=3864.92708pt, Y=139.62904pt, L=-0.3575733981, 
> F=42.2991130810) //
> ///thCalibrate3 (X=-0.2183pt, Y=967.96619pt, L=-0.3641616744, 
> F=42.3001613659) //
> ///thCalibrate4 (X=3886.86893pt, Y=847.47388pt, L=-0.3575359218, 
> F=42.3000087771) //
> ///thCalibrate5 (X=21.72351pt, Y=1675.81102pt, L=-0.3641242900, 
> F=42.3010570667) //
> ///thCalibrate6 (X=1965.26714pt, Y=1615.56487pt, L=-0.3608113605, 
> F=42.3009808177) //
> ///thCalibrate7 (X=3908.81078pt, Y=1555.31871pt, L=-0.3574984437, 
> F=42.3009044731) //
> ///thCalibrate8 (X=1943.32529pt, Y=907.72003pt, L=-0.3608487917, 
> F=42.3000851193) //
> ///thCalibrate (HS=3913.97253pt, VS=1573.34683pt, HD=546.7244489428)/
>
> All the information is here:  pdf coordinates (X,Y), real coordinates 
> (L,F) and the pdf width (HS) and height (VS).
>
> You only need know the width and height from the generate PGN, and you 
> have all the data to do the calculation.
>
> The reverse engineering is to understand the ".map" format and found 
> in the tcl file (mapcalc.tc) the equations to do the conversion.
>
> Regards,
>
> Evaristo.
>
>
> El 26/03/2018 a las 12:57, Nikita Kozlov via Therion escribió:
>> You can export 2 PNGs one with grid to put GCPs on, and second PNG 
>> without grid, but exactly same size (in pixels).
>> And use GCPs put on first grid-equipped PNG to georeference second 
>> "grid-free" PNG.
>>
>> Grid is used only to get pixel coordinates.
>>
>> Dealing with pdf and 'reverse engineering' for me seems a bit 
>> complicated stuff,
>> since in addition to 6 georeference parameters, you need to deal with 
>> scale and so on,
>> so I'd rather used quick and dirty solution with grid and rasters.
>>
>>
>>
>>
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>> Therion at speleo.sk
>> https://mailman.speleo.sk/listinfo/therion
>
>
>
>
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