Fayil na Duniya

**Fayil na Duniya** wato *World File*, fayil ne mai layi shida bayyana rubutu sidecar fayil amfani da yanayin bayanai tsarin (GIS) zuwa georeference raster taswirar images. Esri ne ya gabatar da takaddun fayil,   kuma ya ƙunshi amintattun abubuwa shida na wani canjin canji wanda kuma ke bayyana wuri, mizani da juyawar raster akan taswirar

## Ma'anoni

Ma'anar jimla guda shida a cikin fayil na duniya (kamar yadda Esri ya bayyana  ) shine:

* Layin 1: *A* : girman pixel a cikin *x* -zuwa cikin taswirar raka'a / pixel
* Layi na 2: *D* : juyawa game da *y* -axis
* Layi na 3: *B* : juyawa game da *x* -axis
* Layin na 4: *E* : girman pixel a cikin *y-* kwatance a cikin sassan taswira, kusan koyaushe ba shi da kyau 
* Layi na 5: *C* : *x* -n daidaita tsakiyar pixel na hagu na sama
* Layi na shida: *F* : *y* -n daidaita tsakiyar pixel na hagu na sama

Wannan bayanin yana ɓatarwa duk da cewa *sifofin D* da *B* ba juyawa suke ba, kuma cewa *sifofin A* da *E* ba su dace da girman pixel ba idan *D* ko *B* ba sifili ba ne. Ana kiran *sigogin A*, *D*, *B* da *E* a wasu lokutan "x-scale", "y-skew", "x-skew" da "y-scale".

Mafi kyawun kwatancen *A*, *D*, *B* da *E* shine:

* Layin 1: *A* : *x* -ababin ɓangaren fayel pixel ( *x* -scale)
* Layi na 2: *D* : *y* -kwarikin faifan fayel ( *y* -skew)
* Layi na 3: *B* : *x* -kamawa na tsayin pixel ( *x* -skew)
* Layi na 4: *E* : *y - mai* haɗin tsayi na pixel ( *y* -scale), yawanci mummunan
* Layi na 5: *C* : *x* -n daidaita tsakiyar asalin hoton pixel na sama na hagu wanda aka canza zuwa taswira
* Layi na 6: *F* : *y* -n daidaita tsakiyar asalin hoton pixel na sama na hagu wanda aka canza zuwa taswira

Dukkanin sigogi guda huɗu ana bayyana su a cikin sassan taswirar, waɗanda aka bayyana ta hanyar tsarin kwatancen sararin samaniya don raster.

Lokacin da *D* ko *B* ba sifili ba ana ba da faɗin pixel ta:

: \sqrt{A^2+D^2}

kuma tsayin pixel ta

: \sqrt{B^2+E^2}

Fayilolin duniya waɗanda ke bayanin taswira akan tsarin haɗin gwiwar Universal Transverse Mercator (UTM) suna amfani da waɗannan tarurrukan:

* *D* da *B* yawanci 0 ne, tunda galibi ana sanya pixels ɗin hoto don daidaitawa da layin UTM
* *C* shine UTM gabas
* *F* shine UTM komai
* Alwaysungiyoyi koyaushe mita ne ta pixel

Bayanin da ke sama ya shafi hoto mai lankwasa, wanda ba ya juyawa wanda zai iya zama, misali, an zana shi a kan taswirar da aka tsara ta yadda ake so. Idan fayil ɗin duniya yayi bayanin hoto wanda yake juyawa daga ginshikin abin da aka sa gaba, to, to A, D, B da E dole ne a samo su daga canjin da ake buƙata (duba ƙasa). Musamman, A da E ba za su ƙara zama ma'auni na mita / pixel a kan mashigin su ba.

Ana kuma amfani da waɗannan ƙimomin a cikin sauye-sauyen tabbataccen sifa shida:

: 
\begin{bmatrix} x\prime \\
y\prime \end{bmatrix}
= \begin{bmatrix} A & B & C\\
D & E & F\end{bmatrix}
\begin{bmatrix} x \\
y \\
1 \end{bmatrix}

wanda za'a iya rubuta shi azaman wannan daidaitaccen lissafin:

: \begin{align}
x' &= A\,x + B\,y + C \\
y' &= D\,x + E\,y + F
\end{align}

ina:

: *x *' shine lissafin UTM gabas da pixel akan taswira
: *y *' shine lissafin UTM na pixel akan taswira
: *x* shine lambar shafi na pixel a cikin hoton ana kirgawa daga hagu
: *y* shine lambar jere na pixel a cikin hoton ana kirgawa daga sama
: *A* ko *x* -scale; girma na pixel a cikin sassan taswira a cikin *x* -rashiya
: *B*, *D* kalmomin juyawa ne
: *C*, *F* kalmomin fassara ne: *x*, *y* hadewar taswira na tsakiyar pixel na sama-hagu
: *E* ba daidai ba ne na *y* -scale: girman pixel a cikin sassan taswira a *y* -direction

*Y* -scale ( *E* ) ba shi da kyau saboda asalin hoto da tsarin haɗin UTM sun bambanta. Asalin hoto yana cikin kusurwar hagu ta sama, yayin da asalin tsarin haɗin taswira yake a kusurwar hagu ta ƙasa. Valuesimar jere a cikin hoton yana ƙaruwa daga asalin zuwa ƙasa, yayin *da* -an daidaita y a cikin taswirar ke ƙaruwa daga asalin zuwa sama. Yawancin shirye-shiryen taswira basa iya ɗaukar hotunan "juye juzu'i" (ma'ana waɗanda ke da kyakkyawan *y* -scale).

Don tafiya daga UTM (x'y ') zuwa matsayin pixel (x, y) mutum na iya amfani da lissafin:

: \begin{align}
x&=\frac{Ex'-By'+BF-EC}{AE-DB}\\
y&=\frac{-Dx'+Ay'+DC-AF}{AE-DB}
\end{align}

Misali: Asali `falknermap.jpg` shine pixels 800 × 600 (taswirar da ba a nuna ba). `falknermap.jgw` duniya shine falknermap.jgw kuma ya ƙunshi:
 32.0
 0.0
 0.0
 -32,0
 691200.0
 4576000.0
Matsayin hasken tsibirin Falkner akan hoton taswira shine:
 x = 171 pixels daga hagu
 y = 343 pixels daga sama
Wannan yana bada:
 x1 = Mita 696672 na Gabas
 y1 = mita 4565024 Ba Komai
Ba a ba da yankin UTM (grid) don haka masu daidaitawa ba su da tabbas &#x2014; za su iya wakiltar matsayi a kowane yanki na layin grid 120 UTM. A wannan yanayin, an duba kusan latitude da longitude (41.2, &#x2212; 072.7) a cikin wata gazetteer kuma an gano yankin UTM (grid) 18 ne ta amfani da mai canza yanar gizo.

## Fadada sunan fayil
Sunan filen sunan fayil ɗin duniya ya dace da sunan firam ɗin asalin raster, amma yana da sabon sunan filen ɗin daban (kari). Akwai taron kara sunan suna uku wanda aka yi amfani da shi don fayilolin duniya, tare da tallafi mai sauyawa a cikin software.

Conventionaya daga cikin yarjejeniya mai sauƙi tare da tallafi mai yalwa shine a haɗa harafin "w" zuwa ƙarshen sunan firam na raster. Misali, raster mai suna *mymap* .jpg yakamata ya sami fayil na duniya mai suna *mymap* .jpgw .

Conventionarin kiran sunan fayil wanda ke amfani da haɓaka mai haruffa uku don dacewa da babban taron suna na 8.3 yana amfani da halaye na farko da na ƙarshe na ƙarin fayil ɗin raster, sannan "w" a ƙarshe. Misali, anan ga wasu 'yan taron sanya suna don shahararren salon raster:

Taro na uku shine amfani da tsawan fayil .wld, ba tare da la'akari da nau'in fayil ɗin raster ba, kamar yadda GDAL da QGIS ke tallafawa, amma ba Esri ba . 

## Gargajiyance
Lokacin rubuta fayilolin duniya yana da kyau a yi watsi da saitunan gida kuma koyaushe amfani da "." kamar yadda ake rabo gida goma. Har ila yau, ya kamata a ƙayyade lambobin mara kyau tare da harafin "-" kawai. Wannan yana tabbatar da iyakar damar hotunan.

## Duba kuma

* Grid Esri - shigar da irin wannan yanayin a cikin fayil ɗin raster guda ɗaya
* GeoTIFF
* Tsarin MapInfo TAB - sanannen tsarin bayanan vector na kayan aikin GIS software

## Bayanan kula da manazarta


## Hanyoyin haɗin waje

* Kalkaleta na Duniyar Duniya
* Tsarin Duniya
* Tsarin Fayil na Esri na Duniya