Just another WordPress.com site

Platte Carre, Platte Carree, Plate Carrée, Equirectangular, Geographic, Cartesian, Equidistant Cylindrical, Carte Parallelogrammatique…

Those names all refer to the same thing, and it looks like this…

source: NASA composite satellite imagery, Wikipedia.

What Is It?
So many of my page hits come from people googling "Platte Carre" or some spelling variant.  What is it?  It is a geometric method of peeling off the surface of our round earth and flattening it out into a rectangle so that all of the lines of latitude (the horizontals; Y) and longitude (the verticals; X) are straightened and arranged to form an evenly spaced grid (plate carrée is French for "flat square" -a description of the equally spaced lat longs).  One visually obvious byproduct of this projection is increasingly extreme horizontal stretching in the higher latitudes.  Satellite imagery of cities like Helsinki or Anchorage or Sydney end up looking really distorted.

Why Is It?
This is a popular projection in the GIS world because it is able to show the entire world at once.  Also, since the lat long grid is square, it lends itself nicely to the pixel-y row-and-column world of computerized mapping.  As a result, almost all public Web Map Services (WMS) use it.  The reason you are reading this in the first place is probably because you are trying to drape a Platte Carre WMS over a Google Maps or Virtual Earth basemap and things are not lining up (because they use the Mercator projection, not Platte Carre).  Fortunately, Platte Carre maps will line up nicely in the 3D environment (Google Earth, Virtual Earth 3d) because it only requires a linear transformation to be draped over the 3D sphere.

Where Did It Come From?
Marinus of Tyre invented it around 100 ad.  He was a geographer, map maker, and mathematician; pretty much the father of the Latitude Longitude Coordinate System.

More Info…


Wikipedia has a short but good entry on this projection:


Comparing and contrasting Platte Carre and Mercator:


What is Mercator?


Overcoming the projection mismatch:


Map Projections in the 3D environment:


J Archie sent along this note to me correcting my assertion that the Equidistant Cylindrical projection is synonomous with those listed above.  Here is what Archie says…

Equidistant Cylindrical would only be the same as the other projections listed: Platte Carre, Equirectangular etc, if the Earth were a perfect sphere. Where a Platte Carree wall map has the dimensions 180 cm x 360 cm , the Equidistant Cylindrical would have the dimensions 180 cm x 361 cm, taking into account the relatively larger equatorial circumference.


Thanks, Archie!

John Nelson / IDV Solutions / john.nelson@idvsolutions.com



32 responses

  1. mboszko

    Thanks for the excellent description of this projection. I\’m working with building 3D animated globe maps for broadcast, and was just trying to clear up this very question.

    January 1, 2008 at 6:13 pm

  2. Unknown

    wOW Gold Site supply WOW GOld cheats, Wow
    tips in Wow
    game,so you can find more thing about wOw
    cheat guide. For more information of WOw gold, please visit a the super  WOw
    website specialized in selling wow
    We will serve you with cheap WoW gold, cheap woW goLD .

    September 1, 2008 at 4:43 am

  3. Unknown

    power level
    power level
    power level
    power level
    power level
    power level
    power level
    power level -260668708837401

    September 4, 2008 at 2:33 pm

  4. Unknown

    Hi,Do you need advertising displays, advertisement screens, LCD digital signage and LCD signages? Please go Here:www.amberdigital.com.hk(Amberdigital).we have explored and developed the international market with professionalism. We have built a widespread marketing network, and set up a capable management team dedicated to provide beyond-expectation services to our customers.
    amberdigital Contact Us

    September 22, 2008 at 6:05 am

  5. Unknown

    asus u5a battery
    asus u5f battery
    asus u5 battery
    compaq nw8000 battery
    compaq nc8000 battery
    compaq v1000 battery
    compaq nc6000 battery
    compaq nx5000 battery

    compaq n600 battery
    compaq n600c battery
    compaq n610c battery
    compaq n610v battery
    compaq n620c battery
    compaq e500 battery
    compaq e500s battery
    compaq v300 battery
    compaq v500 battery

    compaq pp2060 battery
    compaq nx9000 battery
    compaq nx9005 battery
    compaq nx9010 battery
    compaq nx9020 battery
    compaq n110 battery
    compaq n110s battery
    compaq pp2101x battery
    compaq presario 2100 battery

    compaq ze4000 battery
    compaq f4809a battery
    compaq f4812a battery
    dell inspiron 700m battery
    dell inspiron 710m battery
    dell latitude x200 battery
    dell 8u443 battery
    dell 312-0058 battery
    dell inspiron 1100 series battery

    dell inspiron 1150 battery
    dell d620 battery
    dell d630 battery
    dell latitude d620 battery
    dell inspiron 5150 battery
    dell inspiron 5100 battery
    dell 1501 battery
    dell e1505 battery
    dell kd476 battery

    dell gd761 battery
    dell inspiron 6400

    October 13, 2008 at 4:29 am

  6. Unknown

    Hi,Do you have used LCD monitors, second hand lcd monitors and second hand flat screens? Please go here:www.sstar-hk.com(Southern Stars).We are constantly buying re-usable LCD panels,LCD recycle.The re-usable panels go through strictly designed process of categorizing, checking, testing, repairing and refurbishing before they are re-used to make remanufactured LCD displays and TV sets.Due to our recent breakthrough in testing and repairing technology of LCD, we can improve the value for your LCD panels.

    October 15, 2008 at 11:40 am

  7. Unknown

    您需要二手液晶显示屏、废旧液晶屏么?我们是不折不扣的二手液晶屏、旧液晶屏大批发商,长期大量供应可再利用的旧液晶屏。我公司提供的各种尺寸的二手液晶屏, 不同厚薄如笔记本屏,均已经过我们严格的分类,检验,测试流程。请访问协力液晶屏www.sceondhandlcd.com[bbgbddhcbijiahia]

    November 23, 2008 at 3:08 am

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s