I'm using python and trying to download and create a layer using the exportImage functionality here:3DEPElevation (ImageServer) . I find that I'm able to download a clipped raster from exportImage much faster than using MakeImageServerLayer_management. ExportImage takes less than 15 seconds, where MakeImageServerLayer takes 45+ seconds. So long story short I'd like to use exportImage if possible.
However, sometimes it works great, but sometimes intermittently, I'm receiving a 400 status code when I try to download the image using exportImage. The request to exportImage returns an href link in the json response, but when I try to download and write it to file, the request fails with a 400. When I use retries, the file will sometimes download on subsequent attempts, but sometimes it will never download. Even when I copy the link into a browser.
Can anyone offer an explanation, insight, and/or solution?
My requests config is something like this:
import requests, arcpy, datetime
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry
retry_strategy = Retry(
total=4,
status_forcelist=[400, 429, 500, 502, 503, 504],
method_whitelist=["HEAD", "GET", "OPTIONS"],
backoff_factor=1
)
adapter = HTTPAdapter(max_retries=retry_strategy)
http = requests.Session()
http.mount("https://", adapter)
http.mount("http://", adapter)
And my imageServer code is something like this:
exportURL = r"https://elevation.nationalmap.gov/arcgis/rest/services/3DEPElevation/ImageServer/exportImage?"
clipPoly=r'C:\test.gdb\test_poly'
tempDir=r'C:\temp'
featExtentJSON=arcpy.Describe(clipPoly).extent.JSON
exportParams = {'bbox':featExtentJSON,
'bboxSR':'',
'size':'',
'imageSR':'',
'time':'',
'format':'tiff',
'pixelType':'F32',
'noData':'',
'noDataInterpretation':'esriNoDataMatchAny',
'interpolation':'RSP_BilinearInterpolation',
'compression':'',
'compressionQuality':'',
'bandIds':'',
'mosaicRule':{"mosaicMethod" : "esriMosaicLockRaster","lockRasterIds" : 4968},
'renderingRule':'',
'f':'pjson'
}
def createExport(url, exParams):
exportResponse = http.get(url, params=exParams)
if exportResponse.status_code==200:
fileURL=exportResponse.json()["href"]
return fileURL
def downloadImage():
fileURL = createExport(exportURL, exportParams)
if fileURL.find('/'):
fileName=fileURL.rsplit('/', 1)[1]
r = http.get(fileURL, allow_redirects=False)
if r.status_code==200:
with open(tempDir+'\\'+fileName,'wb') as f:
f.write(r.content)
return fileName
downloadImage()
