1 / 15

Cartographic Standards

Cartographic Standards. Body-Fixed Rotating Co-ordinate Systems Software, and ‘cubes’... 26th September, 2002: Data Prep. Workshop Dave Heather (ESTEC). Body-Fixed Rotating Co-ordinate Systems. There are two fundamental co-ordinate systems in planetary mapping

michaelbryan
Download Presentation

Cartographic Standards

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cartographic Standards Body-Fixed Rotating Co-ordinate Systems Software, and ‘cubes’... 26th September, 2002: Data Prep. Workshop Dave Heather (ESTEC)

  2. Body-Fixed Rotating Co-ordinate Systems • There are two fundamental co-ordinate systems in planetary mapping • Plantocentric (planet at centre, fixed rotator) • Planetographic (planet rotates beneath ‘fixed’ spacecraft or sub-Earth point) • These are discrete from the final map projection

  3. Planetocentric System • Co-ordinates • Origin: COM • Long: increasing to east • Lat: positive to north, from equatorial plane (spherical) • Used for: Mars post-1992, but not exclusively • Pros: Requested officially as a standard by the PDS • Cons: not precise for locating places on planetary surface

  4. Planetographic System • Co-ordinates • Origin: COM • Long: increasing with planet rotation (to west for prograde) • Lat: positive to north, local vertical from equatorial plane • Used for: Mars pre-1992 • Pros: Precise location of surface features, accounts for shape • Cons: no longer standard for PDS

  5. Is this in the label? • GROUP = IMAGE_MAP_PROJECTION • A_AXIS_RADIUS = 1737.4000000 • B_AXIS_RADIUS = 1737.4000000 • C_AXIS_RADIUS = 1737.4000000 • POSITIVE_LONGITUDE_DIRECTION = EAST • MAP_PROJECTION_TYPE = 'SINUSOIDAL_EQUAL-AREA' • MAP_SCALE = 0.1000000 • MAP_RESOLUTION = 303.2334900 • EASTERNMOST_LONGITUDE = 190.0200958 • WESTERNMOST_LONGITUDE = 180.0000000 • MINIMUM_LATITUDE = 48.9868011 • MAXIMUM_LATITUDE = 56.0000000 • CENTER_LONGITUDE = 195.0000000 • REFERENCE_LATITUDE = 0.0000000 • REFERENCE_LONGITUDE = 0.0000000 • MAP_PROJECTION_ROTATION = 0.0000000

  6. Planetocentric (’02 onwards) Inconsistant with previous data Assumes sphere for projections Requires separate model of planet shape for actual planetary positions As measured in space missions Directly compatible with S/W Standard accepted by PDS Planetographic (Pre ’02) Consistent with previous data Acknowledges non-spherical nature of planet Same model for positioning can be used for map projection Requires transformation from space mission measurements Requires transformation for most S/W (simple) Not ‘PDS standard’ The Ongoing Mars Feud

  7. MOC planetocentric MOLA planetographic 0.3 degrees latitude difference max. Equates to 20 km difference max Transformation required! MOC vs MOLA MOLA MOC

  8. What Should We Use Then? • For full PDS compliance, Mars data should be planetocentric • Planetographic will still be acceptable though! • Lander surveys, planetographic more accurate • Conversion is easy and routinely available • BOTTOM LINE: • Use whatever you’re comfortable with!!

  9. Software, ISIS, cubes etc.

  10. Co-ordinate conversion simple and standard for most up to date processing packages Image and Data Processing Packages: ISIS (Geom, Plansinu, etc.) tfiles ENVI IDL VICAR etc. etc. All of these can convert systems and reproject images Some Basic Software Available

  11. What is this ISIS thing? • Integrated Software for Imaging Spectrometers • Uses cubes • MGS, MPF, Clementine, Viking etc. • Geometric, photometric, radiometric etc. • More than 45 geometric routines in ISIS. • See website: http://wwwflag.wr.usgs.gov/isis-bin/isis.cgi

  12. ISIS cubes • 3-dimensional data format • x and y plane containing data • z plane contains stacked bands (for example) • Sub-cube specifier allows processing of any part of a cube.

  13. Cube File Structure ______________________ . / / /| . ^ / backplane / / | } suffix . / /_ _ _ _ _ _ _ _ _/_ _/ | } region . / / / /| | . / d / / / |c | . / n / / / |o | . / a / core / / |r | . / B / / / |n | . / /_________________/___/ e |e | . /----------------> | | | d e|r | . | Sample | | | i n | /| l . | s | | |s a |/ / a . | L p | | | l / / r . | i a | core | |p /|/ t . | n t | | | / / c . | e i | | | / / e . | a | | | / / p . | l |_________________|___|/ / s . v | bottomplane | | / } suffix . |_________________|___|/ } region . spatial ^^^ . suffix region .

  14. The Clementine Example • Raw data to cube clem2isis • Radiometric correction and file merging: calmrg or expmrg • Geometric correction: plansinu and geom • Photometric correction: photom • These are mission specific - generic routines are also available.

  15. Here end-eth the lesson…. Happy data-producing!

More Related