http://bbs.esrichina-bj.cn/ESRI/viewthread.php?action=printable&tid=59229

http://control.blog.sina.com.cn/admin/article/article_add.php

http://geodata.nju.edu.cn/Portal/metadata/viewMetadata.jsp?id=210093-10246

帮一个同学解决envi中Sinusoidal 转 Geographic Lat/Lon的问题。这个只要Sinusoidal 设置对了，转换只是顺道的事。

数据如下：

http://hiphotos.baidu.com/qqzwind/pic/item/e1e3ba1c8701a18be77165ed9e2f07082938feb5.jpg

打开数据-Edit Header-Edit Attributes- map Info --

http://hiphotos.baidu.com/qqzwind/pic/item/ba210024ab18972bf8087768e6cd7b899e510a1c.jpg
主要设置三个地方：投影，左上点坐标、像素空间分辨率。

1： 投影当然选择Sinusoidal 。这样就可以了。

这里面Datum是这个不影响。不过你真要设置也是可以的：

在POLDER格式文档里面有下面的说明

-------------------------------------------------------

Projection: Standard full resolution POLDER grid
* type of projection: Sinusoïdal
* projection parameters:
length of the ellipsoid minor axis: 6356752.3141
length of the ellipsoid major axis: 6378137.0000
* ellipsoïd of reference: GRS 1980

----------------------------------------------------------------

envi里是有GRS 1980这个ellipse参数的。不过你想用的话需要在envi的Datum里，需要envi安装目录下Datum.txt文件，在下面加一行，例如：Sinus_p, GRS 80,0,0,0 。然后重启envi，就可以选择这个Datum了。

2 左上点坐标。这里数据 经度：-180-180, 维度：90-- -90。 Sinusoïdal投影的半径是,6370997m

所以左上点经度的是：-6370997.0*2*!pi/2 = -20015100

左上点维度是6370997.0*2*!pi/4 = 10007500

3 投影分辨率：查文档可知是 1/18度，所以：6370997.0*2*!pi/360/18 = 6177.49
这样就设置完了。

叠加矢量看看效果：

http://hiphotos.baidu.com/qqzwind/pic/item/c3db8313632762d08fc5d31da0ec08fa503dc654.jpg

成功！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！

下一步可以转投影：

结果如下：

http://hiphotos.baidu.com/qqzwind/pic/item/66e0982397dda14415d91b10b2b7d0a20df48673.jpg

头文件信息意义

http://bbs.esrichina-bj.cn/ESRI/viewthread.php?action=printable&tid=59229

1、图中那个Image Cooedinate of Point里Image X和Image Y标示什么意思，应该怎么设置？
2、我的数据打开时显示的Image X和Y都是1.5，是不是反映的数据的性质，不需要做变动？
3、我数据的范围应该是南北纬50°，东西经180°之间，为什么我设置了数据左上角为-180，-50之后（也设置了投影类型），envi打开时显示的左上角经纬度不是180W和50S，而是：

http://bbs.esrichina-bj.cn/ESRI/attachments/forumid_28/091214171974e60a08966827d1.jpg

Entering Map Information for Georeferenced Files
Map information is associated with georeferenced files. In ENVI, the term georeferenced refers to images that are geometrically corrected (that is, rectified) such that they conform to a known projection. To establish the georeferenced data coordinate system, you must know the sample and line coordinates of one pixel (the reference pixel), the pixel size, the map projection, and map coordinates of this pixel.
In ENVI, pixel values always refer to the upper-left corner of the pixel. Map coordinates also typically refer to the upper-left corner of the pixel. However, if you want the map coordinate to reference the middle of the pixel, add 0.5 to the image coordinate of the reference pixel specified in the Map Info field of the header (for example, x = 1.5, y = 1.5 would make the map coordinates refer to the center of the pixel). In the Header Info dialog, click Edit Attributes and select Map Info.

In the Edit Map Information dialog, enter the reference pixel coordinates in the Image Coordinate of Tie Points X and Y fields and the pixel size in the Pixel Size and Rotation X and Y fields. Be sure to enter the pixel size in the units appropriate for your selected projection.

If North is not up in the image, enter a rotation angle in degrees in the Map Rotation field. Measure the angle in a clockwise direction where zero degrees is straight up (see Overlaying Grid Lines).

Select the map projection by clicking on Change Proj and selecting the appropriate projection from the list of projections (see Selecting Map Projection Types).

Enter the coordinates of the reference pixel in the appropriate fields.

The corresponding latitude and longitude are automatically calculated. To view the coordinates, click on the arrow toggle button for Proj.

Click OK. The Header Info dialog appears.

这是envi的帮助，你以后呢，可以经常参照一下help，或许可以帮你解决。