Dear friends!
is it possible to extract xy coordinates of points from the vector point file (esri shapefile) or .gpx file in a format (row/column) corresponded to certain Landsat image. More precisely, can we find and extract the Landsat scene pixel coordinates on that our GPS points are.
Every suggestions are very welcome.
The software we have is following: ArcGis 10.2.2, Grass GIS 7, Matlab R2011b
Regards,
Maria
Use DNRGarmin
http://www.dnr.state.mn.us/mis/gis/tools/arcview/extensions/DNRGarmin/DNRGarmin.html
Hi Maria,
You can use your point files to extract the needed points from Land scene using the sample tool in ArcGIS spatial analyst.
What actually you want to do? do you want to get the value of particular pixel or the location identification? for both you can use the sample tool.
Hope this will help you.
Vijith
In ArcGIS you should georeference your image and then extract your points.
In Matlab, you can import your image and its geolocation file. In geolocation file, geocoordinates of each pixel are known or calculated with a simple relationship which is defined in that file.
I used Matlab to import large number of satellite data. It is the best for extracting and analyzing large number of satellite data. To give more information about samples done by Matlab, you can refer to my papers:
"Investigation the Behavior of MODIS Ocean Color Products under the 2008 Red Tide in the Eastern Persian Gulf"
and
" Investigation and validation of MODIS SST in the northern Persian Gulf"
Thank you for your suggestions.
It is really not a problem to extract raster pixel values by vector point file say in ArcGis. But it is not a case. We actually don't need the values but Landsat scene pixel coordinates in xy format (row and column corresponded to the georeferenced points)
Your landsat scene has the coordinate of the corners, and you know how many rows and collumns you have on an image, you should therefore be able to calculate the location of each pixel as a x,y position. You can then verify it by comparing the data you get from a linear calculation using the pixel as unit value.
You should be able to extract it with a simple routine in Matlab or any of your favourite program...
In my site:
http://www2.env.aegean.gr/labs/Remote_sensing/EnglishBlock/Remote_sensing2.htm
in the tab: I have written myself several educational programs one of them is:
3. Transverse Mercator Projection Coordinate transformation from Ellipsoid to datum and opposite
You may download and at least you will understand the process. The theoretical analysis and mathematical formulation is in my book "Topographic Mapping" at the Amazon.
Landsat scenes are already in Universal Transverse Mercator (UTM) projection, and its coordinates are rectangular (x, y). GPS points are in World Geodetic System 1984 (WGS84), and coordinates are angular (latitude, longitude).
You should transform GPS vector points to the UTM projection (v.proj in GRASS), and coordinates will perfectly match with Landsat scene in UTM. Than you could calculate x,y coordinates of each vector point (maybe calculate geometry in ArcGIS, or v.to.db in GRASS), which will correspond to the coordinates on the Lansat scene.
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