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--- howtos:how_to_download_features_using_the_arcgis_rest_api [2024-09-24 06:41 am] – hcho
+++ howtos:how_to_download_features_using_the_arcgis_rest_api [2024-09-24 07:35 am] (current) – hcho
@@ Line 1: / Line 1: @@
 ====== How to download features using the ArcGIS REST API ======
-This script is just an example of using the ArcGIS REST API to download DFIRM panel features, but if you know the URL of an ArcGIS REST service, you can easily adapt it.
+This script requires [[https://jqlang.github.io/jq/|jq]].
-<code bash>
-./download_arcgis_rest_features.sh https://hazards.fema.gov/arcgis/rest/services/FIRMette/NFHLREST_FIRMette/MapServer/1 firm_panels
-</code>
 <file bash download_arcgis_rest_features.sh>
 #!/bin/sh
 if [ $# -lt 2 ]; then
-	echo "Usage: download_arcgis_rest_features.sh REST_URL filename_prefix"
+	echo "Usage: download_arcgis_rest_features.sh REST_URL output"
 	exit
 fi
@@ Line 17: / Line 13: @@
 rest_url=$1
-# filename prefix
+# output filename
-prefix=$2
+output=$2
+# prefix
+prefix=$(echo $output | sed 's/\..*//')
 # starting record offset
@@ Line 25: / Line 24: @@
 count=2000
-url="$rest_url/query?where=1%3D1&text=&objectIds=&time=&geometry=&geometryType=esriGeometryEnvelope&inSR=&spatialRel=esriSpatialRelIntersects&distance=&units=esriSRUnit_Foot&relationParam=&outFields=*&returnGeometry=true&returnTrueCurves=false&maxAllowableOffset=&geometryPrecision=&outSR=&havingClause=&returnIdsOnly=false&returnCountOnly=false&orderByFields=OBJECTID&groupByFieldsForStatistics=&outStatistics=&returnZ=false&returnM=false&gdbVersion=&historicMoment=&returnDistinctValues=false&resultOffset=---OFFSET---&resultRecordCount=$count&returnExtentOnly=false&datumTransformation=&parameterValues=&rangeValues=&quantizationParameters=&featureEncoding=esriDefault&f=geojson"
+url="$rest_url/query"
+# required parameters
+url="$url?f=geojson"
+url="$url&where=1%3D1"
+url="$url&outFields=*"
+url="$url&resultRecordCount=$count"
+url="$url&resultOffset=---OFFSET---"
+# optional parameters
+# &text=
+# &objectIds=
+# &time=
+# &geometry=
+# &geometryType=esriGeometryEnvelope
+# &inSR=
+# &spatialRel=esriSpatialRelIntersects
+# &distance=
+# &units=esriSRUnit_Foot
+# &relationParam=
+# &returnGeometry=true
+# &returnTrueCurves=false
+# &maxAllowableOffset=
+# &geometryPrecision=
+# &outSR=
+# &havingClause=
+# &returnIdsOnly=false
+# &returnCountOnly=false
+# &orderByFields=OBJECTID
+# &groupByFieldsForStatistics=
+# &outStatistics=
+# &returnZ=false
+# &returnM=false
+# &gdbVersion=
+# &historicMoment=
+# &returnDistinctValues=false
+# &returnExtentOnly=false
+# &datumTransformation=
+# &parameterValues=
+# &rangeValues=
+# &quantizationParameters=
+# &featureEncoding=esriDefault
 # infinite while loop; : mean true, so while : means while true, which means forever;
@@ Line 31: / Line 71: @@
 while :; do
         # generate a filename
-        fn=${prefix}_$offset.json
+        fn=${prefix}_$offset.geojson
         [ -f $fn ] || wget -O $fn "$(echo "$url" | sed "s/---OFFSET---/$offset/")"
 	# read wget error
@@ Line 49: / Line 89: @@
         offset=$(expr $offset + $count)
 done
+# merge geojson files
+jq 'reduce inputs.features as $s (.; .features += $s) | del(.properties)' *.geojson > $output
 </file>
+Here is an example:
+<code bash>
+./download_arcgis_rest_features.sh https://hazards.fema.gov/arcgis/rest/services/FIRMette/NFHLREST_FIRMette/MapServer/1 firm_panels
+</code>