Tag Info

Hot answers tagged

5

Since Landsat satellites are not placed a true polar orbit -- they are in a "near polar" orbit -- their heading (azimuth) is never zero. See NASA's Landsat Handbook and Landsat Science. It is closest to zero at the equator (8.2°) but deviates from this the closer it gets to the poles. Thus, yes, knowing the center coordinates (latitude, actually) of the ...


4

For anyone needing this: function computeAngle(pointA, pointB){ var dLon = (pointB.x - pointA.x) * Math.PI / 180; var lat1 = pointA.y * Math.PI / 180; var lat2 = pointB.y * Math.PI / 180; var y = Math.sin(dLon) * Math.cos(lat2); var x = Math.cos(lat1)*Math.sin(lat2) - ...


4

Bearing Distance To Line (Data Management) Creates a new feature class containing geodetic line features constructed based on the values in an x-coordinate field, y-coordinate field, bearing field, and distance field of a table. bearing_units (Optional) The units of the values in the Bearing Field. DEGREES —Values in decimal degrees; this ...


4

For accurate calculations, convert (lat, lon, elevation) directly to earth-centered (x,y,z). (If you don't do this, you need to retain additional information about the local normal ["up"] directions in order to compute angles accurately at nonzero elevations.) Elevation Given two points (x,y,z) and (x',y',z') in an earth-centered coordinate system, the ...


3

If the data you will be using is on the scale of the given example, you can treat the problem and Earth as flat without significant accuracy loss. If that does not violate your use case, then calculate the metric shift for both dimensions like you had a triangle and convert it back to degrees. The only tricky part is that the longitude degrees are not of ...


3

The Generate Near Table tool (under Analysis Tools > Proximity) will get you started. You can give the tool a search radius around your reference points and tell it to find the 4 nearest other points, it will calculate the distance and angle to each of the 4 points from the reference point. Make sure the Angle box is checked, Find Only Closest Feature is ...


2

I have attached a simple ArcGIS model that converts 1) source point coordinates 2) a bearing distance (angle) and 3) distance to a point shapefile. The only input is a .dbf or .csv file of your source point coordinates, bearing and distance. The output should be exactly what you are looking for. Best of luck!


2

Eventually, I came up with a good result. This is the procedure I followed to estimate Landsat azimuth at my location. I drew two segments in a GIS, one for each side of my scene (left and right, see figure 1), and added four ("real") corner points on the end of them (green points). This is done in the Reference System of the specific scene (in my case is ...


2

Ok, I've figured this out. Steps are as follows: Use a PolylineAnalyzer and output segments only (this method is better, but slower than just using a Chopper transformer as it outputs angles of segments). Intersect the segments using an Intersector transformer and output nodes. Store incoming segments in a list. Ensure the intersection nodes are not ...


1

The problem was that I was calculating the angle for the marker symbol variable, rather than each instance of the symbol added to the graphics array. I changed the loop where the graphics are added, so that each new addition created a new instance of the marker symbol with its own angle calculated. Now the orientation of the symbol stays consistent.


1

PolylineAnalyzer (from the FME Store) you can type 'PolylineAnalyzer' on the workbench worksheet and download from there. Takes polylines and polygons and analyzes relationships between their components - vertices and segments. FME Store link https://store.safe.com/transformers/polylineanalyzer usage: You can work the angle out and then use a ...


1

If the LineOnLineOverlayer (According to the help files) does indeed give a list of the lines associated with the intersection. You could get the line start and end vertices for each line (CoordinateExtractor) perhaps after clipping to a small area around the intersection. Then it's into the 'ExpressionEvaluator' for some back to basics trigonometry to get ...



Only top voted, non community-wiki answers of a minimum length are eligible