Opening KML file from ArcGIS server with GDAL?

Question

I am able to open the google KML sample by running:

ds = gdal.OpenEx( fn, 0 )

But when using a specific file that I get from my country's database, it doesn't work. I've solved the problem by converting the file into a GPX using GPSBabel but I am sure there must be a better way of doing it. By the way when I run on my .gpx:

from osgeo import gdal, ogr

# File converted from KML to GPX by GPSBabel.
fn = r"D:\Downloads\POT_DONDE_VIVE_LA_GENTE.gpx"

ds = gdal.OpenEx( fn, 0 )
cnt = ds.GetLayerCount()

for i in range( 0, cnt ):

    print( ds.GetLayer(i).GetExtent() )

I get:

(0.0, 0.0, 0.0, 0.0)
(0.0, 0.0, 0.0, 0.0)
(0.0, 0.0, 0.0, 0.0)
(0.0, 0.0, 0.0, 0.0)
(0.0, 0.0, 0.0, 0.0)

That tells me that there must something wrong. The file works perfectly when using the ArcGISWebViewer.

So my questions are, how can I read KML files that output:

IOError: Could not open 'fileName'

with GDAL/OSGEO?, and if the only way is to convert them first to a different file format(how to it within python?) how can I be sure that the output of the conversion matches the original file?

That KML doesn't contain any geometry, it contains a network link to an ArcGIS Server service. You can't open the KML with GDAL. You might be able to extract a map (picture in jpg or png format) from the WMS that the ArcGIS Server provides. — user2856, Jan 31 '19 at 06:31
There's ~1700 features, you can grab 100 at a time using the query endpoint — user2856, Jan 31 '19 at 20:50
I found a javascript script that did it for me its called AGStoShapefile. — Felipe Gutierrez, Jan 31 '19 at 22:25
Does anyone has a good source to converting Shapefile or GEOJson to raster? — Felipe Gutierrez, Jan 31 '19 at 22:26
Yes I know about that function but I haven't been able to implement it, I get an error on the fourth parameter do you know of any example that I could use? The ones I've came across didn't help — Felipe Gutierrez, Feb 01 '19 at 00:22

Paulo Raposo · Answer 1 · 2019-02-02T20:34:45.127

2

GDAL doesn't open KML files, but OGR does.

from osgeo import ogr

fn = r"D:\Downloads\POT_DONDE_VIVE_LA_GENTE.kml"
driver = ogr.GetDriverByName('KML')
dataSource = driver.Open(fn, 0) # 0 means read-only. 1 means writeable.

There are many code examples here: https://pcjericks.github.io/py-gdalogr-cookbook/vector_layers.html#get-shapefile-feature-count. And the file format code 'KML' can be looked up here: https://www.gdal.org/ogr_formats.html.

edited Feb 02 '19 at 20:34

answered Jan 31 '19 at 05:30

Paulo Raposo

1,930
14
21

I have tried that also, and the issue is the file itself as with the code I supplied I am able to open the google sample, so that shouldn't solve the problem, but I am gonna give it a try and let you know. Thanks anyway. – Felipe Gutierrez Jan 31 '19 at 05:35
1

Not all KMLs are vector. – user2856 Jan 31 '19 at 07:35
user2856 True, they're mark-up files that might contain vector data, or raster. I've edited my answer to not imply that KML is always vector. – Paulo Raposo Feb 02 '19 at 20:36
By the way you don't need ogr gdal.OpenEx() does it as well – Felipe Gutierrez Feb 02 '19 at 22:29
Well not in python but if you are using the C# bindings it does make a difference – Felipe Gutierrez Feb 10 '19 at 05:24

Felipe Gutierrez · Accepted Answer · 2019-02-01T17:15:38.500

0

As user2859 said, the KML from the ArcGIS server only contains a link to the file online, and through the webpage query you can only download 100 features at a time, but using a script called AGStoShapefile I've been able to download the whole layer at a time.

edited Feb 01 '19 at 17:15

answered Feb 01 '19 at 00:28

Felipe Gutierrez

129
7

I'm glad you found a solution! But for future readers' sake, this doesn't answer the original question, in which you ask how to open KML files using GDAL. – Paulo Raposo Feb 02 '19 at 20:41
I've edited the question so that future readers don't get confused. – Felipe Gutierrez Feb 02 '19 at 20:56

Opening KML file from ArcGIS server with GDAL?

2 Answers2