XYZ Contour Superimposed on Google Earth Image
tmaguire
Mon, 10/17/2011 - 05:04 pm
I’m brand new to Igor and entirely self-taught from this message forum and the tutorial videos. So here’s what I’m trying to do.
I collected slope data on a nearby beach, I converted all my polar coordinates to Cartesian, and put the whole thing into Igor as XYZ data. I was able to create a contour map, now I would like to superimpose the contour map on a Google Earth (or whatever) image. I have the lat/long for my (0,0) point. Does anyone have any suggestions?
Thanks!
Tim
Your XYZ contour is drawn in a rectangular coordinate system. Google maps are typically viewed using some projection so that straight grid lines from your real domain are going to be mapped into curves. If you know the projection used for your Google map you can apply it to the contour traces so that they match; superimposing one on top of the other is then simply a matter of displaying the Google image using:
followed by
If you don't know the projection of the Google map it will be more complicated especially if you require high accuracy.
A.G.
WaveMetrics, Inc.
October 17, 2011 at 05:34 pm - Permalink
A.G.
Thanks for your reply, I'm still not able to make this work however.
When I enter the NewImage command "expected wave name" comes up as an error. I then clicked explain operation and put in "NewImage [/F/G=g /HIDE=h /HOST=hcSpec /K=k /N=name /S=s ] matrix" filled in the g,h... and so on, but still get the "expected wave name"... any advice?
_Tim
October 18, 2011 at 06:00 pm - Permalink
The commands that I suggested were based on the assumption that you were able to import the Google map image into IGOR. If that is the case then odds are that the image is represented in IGOR by a 3D wave (this is the resulting format when you import a jpeg or png image). So, suppose you imported that image and named it "wave3D". To display this wave you would execute the command:
The error message that you are reporting suggests that you do not have a wave by that name in the current data folder. Since you are new to IGOR you may not be familiar with the Data Browser. I suggest that you try using it (Data Menu->Data Browser). If you check all the check boxes on the left hand side of the Data Browser window you should be able to see icons representing all data objects in your experiment. Identify the wave that corresponds to the loaded Google image, right-click on it and select New Image. That should be equivalent to the command above.
After you have displayed the image you can attempt to add the contour map on top using AppendMatrixContour. I assume that before you try this you have considered the issues of projections and scaling mentioned in my previous post.
A.G.
WaveMetrics, Inc.
October 19, 2011 at 11:07 am - Permalink