Re: scale error for each pixel
Markus Neteler <[email protected]>
| Newsgroups | gmane.comp.gis.grass.user |
|---|---|
| Message-ID | <CALFmHhurHARWWLWHKte-Ob-m_U9k=b3MsRtmMO7jG=dMORe=uA@mail.gmail.com> |
Dear Ken, On Thu, Nov 9, 2017 at 12:30 PM, Ken Mankoff <[email protected]> wrote: > On 2017-11-02 at 07:17, Helmut Kudrnovsky <[email protected]> wrote: >> Ken Mankoff wrote >>> Does GRASS (or GDAL?, proj4?) have a function (or addon) to provide the >>> scale error for a given cell? >>> >>> My understanding is that for a given projection, the "lat_ts" term of >>> the proj4 string describing the projection is where 1 m in GRASS is >>> actually 1 m. Elsewhere, errors grow. I'd like to track these. >> >> AFAIR there is now an area function in r.mapcalc in GRASS trunk to >> calculate the pixel area. > > Is the scale error only in longitude and never in latitude? Or can it be in both? > Is there a way to find the error for a length error rather than an area error? > Specifically, for a vector line with an arbitrary heading? This is probably a question for the PROJ mailing list? Markus _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user