[Proj] Converting to WGS84 Latitude/Longitude

[Artur Bercik]

On Fri, Oct 24, 2014 at 7:30 PM, Charles Clercq <charles.clercq at gmail.com>
wrote:

> Dear all,
>
> I found a pdf document:
> http://www.yale.edu/ceo/Documentation/MODIS_data.pdf
>
> which state: "The data are provided in the HDF-EOS format. MODIS data at
> version 4 and above use
> the Sinusoidal projection with the WGS84 datum. A very small sample of
> common
> products are listed below."
>
> Hope it helps
>

Thank you Charles. However, the statement you have found is for land
products, and I am using atmospheric products. In this case, the data are
provided in geographic coordinate system. The pair of lats and lons I have
read are in geographic coordinate system, but do not know the datum.

>
>
> 2014-10-24 9:30 GMT+02:00 Artur Bercik <vbubbly21 at gmail.com>:
>
>>
>>
>> On Fri, Oct 24, 2014 at 3:50 PM, Mikael Rittri <
>> Mikael.Rittri at carmenta.com> wrote:
>>
>>>   Hi Artur.
>>>
>>>
>>>
>>> It could be the same thing. “Geodetic” latitude is the same as ordinary,
>>>
>>> everyday latitude. There are some other flavours of latitude as well,
>>>
>>> auxiliary latitudes that are mainly used to simplify some kinds of
>>>
>>> computations, but “geodetic” is the ordinary kind.
>>>
>>>
>>>
>>> For longitudes, there is only one flavour, but the zero meridian is
>>>
>>> not always Greenwich.
>>>
>>>
>>>
>>> So the coordinates you mention could be in WGS84 Lat/Long already.
>>>
>>> But it is not certain, since they could be expressed in some other
>>>
>>> geodetic datum that uses a different ellipsoid.
>>>
>>>
>>>
>>> Do you have any documentation about the geodetic datum of your
>>> coordinates (like Pulkovo 1942, Pulkovo 1995, PZ 1990, or WGS84),
>>>
>>> or about the ellipsoid used?
>>>
>>
>> Dear Mikael Rittri
>>
>> Thanks for your answer.
>> Actually, I could not understand which datum or ellepsoid was used. The
>> following documents says only geodetic latitude and longitude:
>>
>> http://modaps.nascom.nasa.gov/services/about/products/MOD03.html
>>
>> I have read the above data product; and retrieved the pairs of geodetic
>> lats and lons as the document says, but could not figure out if  I should
>> convert them into WGS84 or not. I have to compare the data using above
>> product with other data which are in WGS84 lats and lons.
>>
>>>
>>>
>>> Best regards,
>>>
>>>
>>>
>>> Mikael Rittri
>>>
>>> Carmenta
>>>
>>> Sweden
>>>
>>> http://www.carmenta.com
>>>
>>>
>>>  ------------------------------
>>>
>>> *From:* proj-bounces at lists.maptools.org [mailto:
>>> proj-bounces at lists.maptools.org] *On Behalf Of *Artur Bercik
>>> *Sent:* Friday, October 24, 2014 8:27 AM
>>> *To:* proj at lists.maptools.org
>>> *Subject:* [Proj] (no subject)
>>>
>>>
>>>
>>> Dear Proj list members:
>>>
>>> Being a very new in this field, could someone answer me about the
>>> following problem:
>>>
>>> I have a pair of Geodetic Latitude and Geodetic Longitude (50.89524,
>>> 117.69043).
>>> How can I convert it into Latitude and Longitude with WGS84 Ellepsoid?
>>>
>>> Thanks in the advance.
>>>
>>> Artur
>>>
>>> _______________________________________________
>>> Proj mailing list
>>> Proj at lists.maptools.org
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>>>
>>
>>
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