# Finding the rectangular domain that covers an oblique area **URL:** \ **Category:** Q&A\ **Created:** [May 4, 2022, 10:06am UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872 "2022-05-04T10:06:25Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://forum.generic-mapping-tools.org/u/Andreas)\ **Post date:** [May 4, 2022, 10:06am UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/1 "2022-05-04T10:06:25Z")
My script looks like this (1st figure): ``` gmt pscoast -Bafg -JS36/90/30c -R-15/60/68/90 -Ggray -png pie ``` I would like to make this a rectangular map instead, i.e. I have to provide a `-Rw/s/e/n+r`. To obtain this I do: ``` $ gmt mapproject -JS36/90/30c -R-15/60/68/90 -Wn0/0 -1.85242110467 62.3326996594 $ gmt mapproject -JS36/90/30c -R-15/60/68/90 -Wn1/1 126 80.9626773189 ``` and use this in `-R` (2nd figure): ``` gmt pscoast -Bafg -JS36/90/30c -R-1.85242110467/62.3326996594/126/80.9626773189+r -Ggray -png rectangular ``` Reading about [mapproject -Wr/R](https://docs.generic-mapping-tools.org/dev/mapproject.html#w): ``` To output the rectangular domain that covers an oblique area as defined by -R -J, append r, or use R to get the result in -Rw/e/s/n string format. ``` I was hoping that this would give me the wanted `-R`: ``` $ gmt mapproject -JS36/90/30c -R-15/60/68/90 -WR -R-15/60/68/90 ``` But obviously this just gives me the input `-R`. I don’t understand when `mapproject -Wr/R` would give valuable information. Am I misunderstanding the description of `mapproject -Wr/R`? Is there any way of getting `-R-1.85242110467/62.3326996594/126/80.9626773189+r` out of `mapproject` given `-JS36/90/30c -R-15/60/68/90`? ![pie](https://canada1.discourse-cdn.com/flex047/uploads/gmt/original/2X/2/211069221053163b5a70616c8e81cb3b9099364f.png) ![rectangular](https://canada1.discourse-cdn.com/flex047/uploads/gmt/original/2X/3/3ce1ac6811de1331554e57c0a19b883f6e2e8257.png) ---
**Author:** ![mkononets](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/mkononets/32/4029_2.png) [@mkononets](https://forum.generic-mapping-tools.org/u/mkononets)\ **Post date:** [May 4, 2022, 6:28pm UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/2 "2022-05-04T18:28:20Z")
> [@Andreas](#): > > `the rectangular domain that covers an oblique area` it says “oblique”, that is, oblique Mercator, not stereographic. you are specifying JS… = stereographic. But thanks anyway, personally I liked the question. ---
**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://forum.generic-mapping-tools.org/u/Andreas)\ **Post date:** [May 4, 2022, 9:15pm UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/3 "2022-05-04T21:15:18Z")
Why mercator? In [gmt.conf](https://docs.generic-mapping-tools.org/dev/gmt.conf.html#term-MAP_ANNOT_OBLIQUE) _oblique_ is defined as ``` This setting applies to “oblique” projections, which in this context means maps whose boundary is a rectangle not specified by meridians and parallels ``` ---
**Author:** ![mkononets](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/mkononets/32/4029_2.png) [@mkononets](https://forum.generic-mapping-tools.org/u/mkononets)\ **Post date:** [May 4, 2022, 9:36pm UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/4 "2022-05-04T21:36:21Z")
yet another context I believe while the examples on the `mapproject`'s manual page explicitly use oblique Mercator projection ---
**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://forum.generic-mapping-tools.org/u/Andreas)\ **Post date:** [May 4, 2022, 9:38pm UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/5 "2022-05-04T21:38:44Z")
Yes. Thanks. I’ll have a closer look at the docs. Can’t understand why this is so confusing to me. ---
**Author:** ![mkononets](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/mkononets/32/4029_2.png) [@mkononets](https://forum.generic-mapping-tools.org/u/mkononets)\ **Post date:** [May 4, 2022, 10:24pm UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/6 "2022-05-04T22:24:07Z")
what I wrote was probably totally wrong. you wrote: I would like to make this a rectangular map instead, i.e. I have to provide a `-Rw/s/e/n+r`. `mapproject`'s option `-WR` gives `-Rw/e/s/n`. This is rectangular _but not oblique_, so it returns a copy of your `-R-15/60/68/90`. Note the difference: you want `-Rw/s/e/n+r` while `-WR` gives `-Rw/e/s/n`. `-WR` does not do what you want. ---
**Author:** ![pwessel](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/pwessel/32/30_2.png) [@pwessel](https://forum.generic-mapping-tools.org/u/pwessel)\ **Post date:** [May 6, 2022, 8:48pm UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/7 "2022-05-06T20:48:51Z")
See new documentation and illustration for **-W** in **mapproject** at the [dev version](https://docs.generic-mapping-tools.org/dev/mapproject.html) documentation. ---
**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://forum.generic-mapping-tools.org/u/Andreas)\ **Post date:** [May 9, 2022, 11:45am UTC](https://forum.generic-mapping-tools.org/t/finding-the-rectangular-domain-that-covers-an-oblique-area/2872/8 "2022-05-09T11:45:24Z")
As Paul wrote, this is now implemented. And I can do this: ```auto gmt mapproject -JS36/90/30c -R-15/60/68/90 -WE -R-1.852421104674526/62.33269965938534/126/80.96267731894207+r ``` which answers my question. Slick.