Hello. I am new in this new Forum.
With the Interpolate Tool (form 3D Analyst, Functional Surface) I need to calculate the length (in metres) of a rivers polyline shp file.
I already have TIN and DEM. The shape file is in WGS 1984 and the country is Panama.
However, Arc Map help tells me that: "You can only calculate the area, length, or perimeter of features if the coordinate system being used
is projected. Keep in mind that different projections have different spatial properties and distortions. If the coordinate system of the data
source and data frame are not the same, you may get a different result if you calculate geometry using the data frame's coordinate system than
when you calculate using the data source's coordinate system. It is recommended that an equal-area projection be used when calculating areas."
How can I project it with an equal-area projection to use the Interpolate Tool? Where can I find the projection data for Costa Rica, Nicaragua, Honduras, El Salvador and Guatemala to use with the Interpolate Tool.
Thanks in advance for your response,