diff --git a/js/main.ts b/js/main.ts
index 645f046..7321850 100644
--- a/js/main.ts
+++ b/js/main.ts
@@ -43,7 +43,7 @@ function getCurrentPosition(): Promise<GeolocationPosition> {
 
 const [lon1, lat1, lon2, lat2] = sainteAdeleBBox;
 const adresse = document.getElementById("adresse");
-if (adresse == null)
+if (adresse === null)
   throw "Element not found: adresse";
 const autocomplete = new GeocoderAutocomplete(
   adresse,
@@ -72,6 +72,8 @@ window.addEventListener("load", async () => {
 });
 
 function categorieTexte(info) {
+  if (info === null)
+    return "inconnu";
   const { zone, milieu, description } = info;
   const [categorie, souscategorie] = milieu.split(".");
   const cat = zonage.categorie_milieu[categorie];
@@ -85,6 +87,8 @@ function categorieTexte(info) {
 }
 
 function milieuTexte(info) {
+  if (info === null)
+    return "inconnu";
   const { zone, milieu, description } = info;
   const mil = zonage.milieu[milieu];
   if (mil !== undefined) {
@@ -96,12 +100,16 @@ function milieuTexte(info) {
 }
 
 function collecteTexte(info) {
+  if (info === null)
+    return "inconnue";
   const { couleur, jour } = info;
   return `${jour} <a target="_blank" href="${COLLECTES_URL}">(calendrier PDF)</a>`;
 }
 
 function conseilTexte(info) {
-  return `<a href="mailto:district${info.numero}@vdsa.ca">${info.conseiller}</a>`;
+  if (info === null)
+    return "inconnu";
+  return `conseillier: <a href="mailto:district${info.numero}@vdsa.ca">${info.conseiller}</a>`;
 }
 
 const geoformat = new GeoJSON();
@@ -111,12 +119,12 @@ const zonelayer = new VectorLayer<any>({  // stfu tsc
 });
 function updateInfo(info) {
   const infoDiv = document.getElementById("info");
-  if (infoDiv == null)
+  if (infoDiv === null)
     throw "Element not found: info";
   const { zone, district, collecte } = info;
   infoDiv.innerHTML = `<table>
-<tr><td>District</td><td>${district.numero}: ${conseilTexte(district)}<td></tr>
-<tr><td>Zone</td><td>${zone.zone}</td></tr>
+<tr><td>District</td><td>${district.numero} (${conseilTexte(district)})<td></tr>
+<tr><td>Zone</td><td>${zone.zone ?? "inconnue"}</td></tr>
 <tr><td>Catégorie</td><td>${categorieTexte(zone)}<td></tr>
 <tr><td>Milieu</td><td>${milieuTexte(zone)}<td></tr>
 <tr><td>Collecte</td><td>${collecteTexte(collecte)}<td></tr>
@@ -134,7 +142,7 @@ function updateInfo(info) {
 
 function infoError(txt: string) {
   const infoDiv = document.getElementById("info");
-  if (infoDiv == null)
+  if (infoDiv === null)
     throw "Element not found: info";
   infoDiv.innerHTML = `<p>${txt}</p>`;
 }
@@ -182,7 +190,7 @@ async function geolocateMe() {
 }
 
 const locate = document.getElementById("locate");
-if (locate == null)
+if (locate === null)
   throw "Element not found: locate";
 locate.addEventListener("click", geolocateMe);
 
diff --git a/zonalda/__init__.py b/zonalda/__init__.py
index 011c699..63ebdb5 100644
--- a/zonalda/__init__.py
+++ b/zonalda/__init__.py
@@ -9,6 +9,7 @@
 from pathlib import Path
 
 import geopandas  # type: ignore
+from pandas import Series
 from shapely import Point  # type: ignore
 
 VERSION = "0.0.1"
@@ -29,7 +30,9 @@ def __init__(self):
         self.zonage = geopandas.read_file(THISDIR / "zonage.geojson")
         self.collectes = geopandas.read_file(THISDIR / "collectes.geojson")
 
-    def __call__(self, latitude: float, longitude: float):
+    def __call__(
+        self, latitude: float, longitude: float
+    ) -> tuple[Series | None, Series | None, Series | None,]:
         """Chercher les informations citoyennes pour un emplacement."""
         p = Point(longitude, latitude)
         if not self.ville.geometry.contains(p):
@@ -40,19 +43,19 @@ def __call__(self, latitude: float, longitude: float):
         districts = self.districts.loc[self.districts.contains(p)]
         if len(districts) > 1:
             LOGGER.warning("Plusieurs districts trouvé pour %s: %s", p, districts)
-        if districts:
+        if len(districts):
             district = districts.iloc[0]
         zones = self.zonage.loc[self.zonage.contains(p)]
         if len(zones) > 1:
             LOGGER.warning("Plusieurs zones trouvé pour %s: %s", p, zones)
-        if zones:
+        if len(zones):
             zone = zones.iloc[0]
         collectes = self.collectes.loc[self.collectes.contains(p)]
         if len(collectes) > 1:
             LOGGER.warning(
                 "Plusieurs zones de collectes trouvé pour %s: %s", p, collectes
             )
-        if collectes:
+        if len(collectes):
             collecte = collectes.iloc[0]
         return district, zone, collecte
 
diff --git a/zonalda/api.py b/zonalda/api.py
index d43fa8d..498c14c 100644
--- a/zonalda/api.py
+++ b/zonalda/api.py
@@ -54,10 +54,10 @@ def from_wgs84(self, latitude: float, longitude: float) -> "Emplacement":
         district, zone, collecte = zonalda(latitude, longitude)
         return self(
             district=District(numero=district["id"], conseiller=district["Conseiller"])
-            if district
+            if district is not None
             else None,
             collecte=Collecte(jour=collecte["jour"], couleur=collecte["couleur"])
-            if collecte
+            if collecte is not None
             else None,
             zone=Zone(
                 zone=zone["ZONE"],
@@ -66,7 +66,7 @@ def from_wgs84(self, latitude: float, longitude: float) -> "Emplacement":
                 # FIXME: thoroughly unnecessary JSON parsing
                 geometry=json.loads(shapely.to_geojson(zone["geometry"])),
             )
-            if zone
+            if zone is not None
             else None,
         )