# Can't build isochrone map code: 3099 **URL:** \ **Category:** isochrones\ **Created:** [August 21, 2023, 7:54am UTC](https://ask.openrouteservice.org/t/cant-build-isochrone-map-code-3099/5172 "2023-08-21T07:54:58Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![kklr](https://ask.openrouteservice.org/letter_avatar_proxy/v4/letter/k/c6cbf5/32.png) [@kklr](https://ask.openrouteservice.org/u/kklr)\ **Post date:** [August 21, 2023, 7:54am UTC](https://ask.openrouteservice.org/t/cant-build-isochrone-map-code-3099/5172/1 "2023-08-21T07:54:58Z")
Hi, I get an error for specifics coordinates, when trying to build an isochrone map. I’m using ORS Tools in QGIS. I’m trying to build a isochrone map from layer, using the travel mode: “driving car” However, if I change travel mode to cycling, walking or something other than driving car, then I don’t get an error. I can also build the isochrone if I move the point say 50-100m away. These are the coordinates: [50.8803701, 20.6477226] This is from the log: QGIS version: 3.16.16-Hannover QGIS code revision: f5778a89 Qt version: 5.15.2 GDAL version: 3.4.1 GEOS version: 3.10.0-CAPI-1.16.0 PROJ version: Rel. 8.2.1, January 1st, 2022 Processing algorithm… Algorithm ‘Isochrones from Point-Layer’ starting… Input parameters: { ‘INPUT\_AVOID\_BORDERS’ : None, ‘INPUT\_AVOID\_COUNTRIES’ : ‘’, ‘INPUT\_AVOID\_FEATURES’ : [], ‘INPUT\_AVOID\_POLYGONS’ : None, ‘INPUT\_FIELD’ : ‘store’, ‘INPUT\_METRIC’ : 0, ‘INPUT\_POINT\_LAYER’ : Feature ID 478 caused a GenericServerError: 500 ({“error”:{“code”:3099,“message”:“Unable to build an isochrone map.”},“info”:{“engine”:{“build\_date”:“2023-07-09T01:31:50Z”,“version”:“7.1.0”},“timestamp”:1692603373172}}) Execution completed in 0.48 seconds Results: {‘OUTPUT’: ‘Isochrones\_4b27be05\_aee8\_4902\_982f\_16a9e71f1fb6’} Loading resulting layers Algorithm ‘Isochrones from Point-Layer’ finished Thank you in advance ---
**Author:** ![jschnell](https://ask.openrouteservice.org/user_avatar/ask.openrouteservice.org/jschnell/32/971_2.png) [@jschnell](https://ask.openrouteservice.org/u/jschnell)\ **Post date:** [August 21, 2023, 8:43am UTC](https://ask.openrouteservice.org/t/cant-build-isochrone-map-code-3099/5172/2 "2023-08-21T08:43:37Z")
Hey, if I’m not mistaken, you’re trying to build isochrones from the middle of “Galeria Echo” in Kielce, PL. Roads in there are tagged as `highway=path`, only connected to the main road network by `highway=footpath`. Both are excluded from the car routing graph, but not from snapping, meaning that the algorithm will find a starting point on these roads and then try to build an isochrone from there, failing since it can’t move on these roads. Moving the point probably gets the algorithm to snap to a car-feasible road, and thus makes it able to build isochrones. Best regards ---
**Author:** ![kklr](https://ask.openrouteservice.org/letter_avatar_proxy/v4/letter/k/c6cbf5/32.png) [@kklr](https://ask.openrouteservice.org/u/kklr)\ **Post date:** [August 21, 2023, 9:00am UTC](https://ask.openrouteservice.org/t/cant-build-isochrone-map-code-3099/5172/3 "2023-08-21T09:00:43Z")
Thank you so much for your quick answer. Yes, that is where I was trying to set my starting point. I’m fairly new working with this, so I appreciate the help. How / where can you find these tags? ---
**Author:** ![jschnell](https://ask.openrouteservice.org/user_avatar/ask.openrouteservice.org/jschnell/32/971_2.png) [@jschnell](https://ask.openrouteservice.org/u/jschnell)\ **Post date:** [August 21, 2023, 10:19am UTC](https://ask.openrouteservice.org/t/cant-build-isochrone-map-code-3099/5172/4 "2023-08-21T10:19:58Z")
Hey, on OSM, use _Right click_ → _Query features_ on your way to get a list of tags for all objects in the marked circle - choose the object you want, and you’ll get a list. Check the [OSM wiki](https://wiki.openstreetmap.org/wiki/Main_Page) for informations on the tags. Check [here](https://koebi.github.io/openrouteservice/documentation/Tag-Filtering.html) for info on what tags get used in routing. It’s a bit of a learning curve though, if you’re completely new to the OSM world, so be warned 😉 Best regards ---
**Author:** ![kklr](https://ask.openrouteservice.org/letter_avatar_proxy/v4/letter/k/c6cbf5/32.png) [@kklr](https://ask.openrouteservice.org/u/kklr)\ **Post date:** [August 21, 2023, 10:44am UTC](https://ask.openrouteservice.org/t/cant-build-isochrone-map-code-3099/5172/5 "2023-08-21T10:44:56Z")
Thank you! I’ll have a look Cheers