I have two different DataFrames that look something like this:
| Lat | Lon |
|---|---|
| 28.13 | -87.62 |
| 28.12 | -87.65 |
| …… | …… |
| Calculated_Dist_m |
|---|
| 34.5 |
| 101.7 |
| ………….. |
The first DataFrame (name=df) (consisting of the Lat and Lon columns) has just over 1000 rows (values) in it. The second DataFrame (name=new_calc_dist) (consisting of the Calculated_Dist_m column) has over 30000 rows (values) in it. I want to determine the new longitude and latitude coordinates using the Lat, Lon, and Calculated_Dist_m columns. Here is the code I’ve tried:
r_earth = 6371000 new_lat = df['Lat'] + (new_calc_dist['Calculated_Dist_m'] / r_earth) * (180/np.pi) new_lon = df['Lon'] + (new_calc_dist['Calculated_Dist_m'] / r_earth) * (180/np.pi) / np.cos(df['Lat'] * np.pi/180)
When I run the code, however, it only gives me new calculations for certain index values, and gives me NaNs for the rest. I’m not entirely sure how I should go about writing the code so that new longitude and latitude points are calculated for each of over 30000 row values based on the initial 1000 longitude and latitude points. Any suggestions?
EDIT
Here would be some sample outputs. Note that these are not exact figures, but give the idea.
| Lat | Lon |
|---|---|
| 28.13 | -87.62 |
| 28.12 | -87.65 |
| 28.12 | -87.63 |
| ….. | …… |
| Calculated_Dist_m |
|---|
| 34.5 |
| 101.7 |
| 28.6 |
| 30.8 |
| 76.5 |
| …………….. |
And so the sample out put would be:
| Lat | Lon |
|---|---|
| 28.125 | -87.625 |
| 28.15 | -87.61 |
| 28.127 | -87.623 |
| 28.128 | -87.623 |
| 28.14 | -87.615 |
| 28.115 | -87.655 |
| 28.14 | -87.64 |
| 28.117 | -87.653 |
| 28.118 | -87.653 |
| 28.15 | -87.645 |
| 28.115 | -87.635 |
| 28.14 | -87.62 |
| 28.115 | -87.613 |
| 28.117 | -87.633 |
| 28.118 | -87.633 |
| …… | ……. |
Again, these are just random outputs (I tried getting the exact calculations, but could not get it to work). But overall, this gives an idea of what would be wanted: taking the coordinates from the first dataframe and calculating new coordinates based on each of the calculated distances from the second dataframe.
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Answer
If I understood correctly and assuming df1 and df2 as input, you can perform a cross merge to get all combinations of df1 and df2 rows, then apply your computation (here as new columns Lat2/Lon2):
df = df1.merge(df2, how='cross') r_earth = 6371000 df['Lat2'] = df['Lat'] + (df['Calculated_Dist_m'] / r_earth) * (180/np.pi) df['Lon2'] = df['Lon'] + (df['Calculated_Dist_m'] / r_earth) * (180/np.pi) / np.cos(df['Lat'] * np.pi/180)
output:
Lat Lon Calculated_Dist_m Lat2 Lon2 0 28.13 -87.62 34.5 28.130310 -87.619648 1 28.13 -87.62 101.7 28.130915 -87.618963 2 28.13 -87.62 28.6 28.130257 -87.619708 3 28.13 -87.62 30.8 28.130277 -87.619686 4 28.13 -87.62 76.5 28.130688 -87.619220 5 28.12 -87.65 34.5 28.120310 -87.649648 6 28.12 -87.65 101.7 28.120915 -87.648963 7 28.12 -87.65 28.6 28.120257 -87.649708 8 28.12 -87.65 30.8 28.120277 -87.649686 9 28.12 -87.65 76.5 28.120688 -87.649220 10 28.12 -87.63 34.5 28.120310 -87.629648 11 28.12 -87.63 101.7 28.120915 -87.628963 12 28.12 -87.63 28.6 28.120257 -87.629708 13 28.12 -87.63 30.8 28.120277 -87.629686 14 28.12 -87.63 76.5 28.120688 -87.629220